Most tadalafil side effects are mild: in the FDA-approved Cialis labeling, headache, indigestion, back pain, muscle aches, flushing, and stuffy nose lead the list. A few effects are rare but urgent, including an erection lasting more than 4 hours, sudden vision loss, and sudden hearing loss. Your prescriber sets the dose and checks your other medicines.
If you’re searching for tadalafil side effects, you may be weighing a new prescription, or you may have just noticed something odd after a dose and want to know whether it’s normal. Both situations deserve a clear answer. Tadalafil (sold as Cialis and as generics) is a PDE5 inhibitor, meaning a medicine that blocks the enzyme phosphodiesterase type 5 so blood vessels can relax and fill when you’re aroused. Because the medicine acts on blood vessels, its effects can reach beyond the penis.
This guide walks through what the current FDA-approved label reports, how often common effects showed up in clinical trials, which warning signs mean “stop and get help,” and which medicines and health conditions change the safety picture. We’ll keep a strict line between what labeling states and what is only commonly explained. Where something isn’t established, we’ll say so.
We won’t repeat the full drug profile here. For how tadalafil is used for ED, read tadalafil for erectile dysfunction; for the sister drug’s safety profile, see sildenafil side effects; and for how the two medicines differ, see sildenafil vs. tadalafil. Nothing here replaces advice from the clinician who prescribed your medicine, and don’t start, stop, or change a dose on your own.
- The most common labeled effects (headache, indigestion, back pain, muscle aches, flushing, nasal congestion) were usually mild, and rates rose with dose in the as-needed trials.
- Back pain and muscle aches typically start 12 to 24 hours after a dose and usually fade within about 48 hours, according to the label.
- An erection lasting more than 4 hours, sudden vision loss, sudden hearing loss, or chest pain needs urgent medical care.
- Nitrate medicines (and “poppers”) are contraindicated with tadalafil; alpha blockers, blood pressure medicines, alcohol, and some other drugs also change safety.
- Tell your prescriber and pharmacist about every medicine and supplement, including products bought online.
How Common Are Tadalafil Side Effects, According to the Label?
Numbers help most when you know where they came from. The Cialis label reports side effects as percentages from clinical trials, and those percentages can be read in a way that’s calmer and more accurate than a list of scary-sounding terms.
As-needed use: the trial numbers
The as-needed regimen means taking a tablet before anticipated sexual activity. The label’s adverse reaction table is the most reliable starting point for how often common effects occurred, and for how much of that was also seen with a sugar pill.
What the as-needed trial table shows
The label’s table of as-needed trials reports reactions by dose compared with placebo. For headache, 5% on placebo versus 15% on 20 mg, with 11% on both 5 mg and 10 mg. Indigestion (dyspepsia) was 1% on placebo and 4%, 8%, and 10% across those doses. The label says the most common reactions, at 2% or more, were headache, dyspepsia, back pain, myalgia (muscle aching), nasal congestion, flushing, and pain in the limbs.
The table below pulls out those figures. Read it as “what happened in these trial groups,” not as a forecast for you.
| Reaction | Placebo | 5 mg | 10 mg | 20 mg |
|---|---|---|---|---|
| Headache | 5 | 11 | 11 | 15 |
| Dyspepsia (indigestion) | 1 | 4 | 8 | 10 |
| Back pain | 3 | 3 | 5 | 6 |
| Myalgia (muscle aches) | 1 | 1 | 4 | 3 |
| Nasal congestion | 1 | 2 | 3 | 3 |
| Flushing | 1 | 2 | 3 | 3 |
| Pain in limb | 1 | 1 | 3 | 3 |
Source note: FDA-approved Cialis labeling, DailyMed (revised 3/2026), Section 6.1 Table 1. Placebo N=476; 5 mg N=151; 10 mg N=394; 20 mg N=635. Trial groups differ in size and design, and rates in daily-dose or BPH trials are different. These are percentages of men, not a personal risk estimate.
Placebo rates and stopping the medicine
Notice that the placebo column isn’t zero. Some “side effects” happen with a sugar pill too, which is why labels report both columns. Headache at 5% on placebo is a reminder that everyday headaches, stress, and expectations can be mixed into what people report.
The label also reports how many men stopped the medicine because of adverse events. In the as-needed ED trials, the discontinuation rate for men taking 10 or 20 mg was 3.1%, compared with 1.4% on placebo. In plain terms, most men with side effects kept taking it, but a small share did stop. If effects bother you enough that you’re tempted to stop, call the prescriber rather than deciding alone, because other doses or options may exist.
Daily dosing and how to read the tables
Tadalafil can also be prescribed as a lower daily dose, and labeling gives separate numbers for it. Understanding why tables differ keeps you from comparing the wrong things.
Numbers for once-daily use
For once-daily use, the label’s ED table covers 12 weeks. Headache was reported by 5% on placebo, 3% on 2.5 mg, and 6% on 5 mg; dyspepsia by 2%, 4%, and 5%; and back pain by 1%, 3%, and 3%. Flushing was 1%, 1%, and 3%.
For once-daily 5 mg in men treated for benign prostatic hyperplasia (BPH, an enlarged prostate) or both conditions, the label lists headache at 4.1% versus 2.3% on placebo, indigestion at 2.4% versus 0.2%, and back pain at 2.4% versus 1.4%. Different men, doses, and time frames than the as-needed table, so they’re not a direct match. If you’re deciding between regimens, daily vs. as-needed tadalafil lays out the differences in how the labeling describes them.
Why you can’t compare tables across drugs
It’s tempting to set one drug’s side effect table beside another’s and pick the “winner.” Labeling doesn’t support that. Each table comes from separate trials with different men, doses, durations, and ways of asking about symptoms, so a small gap between two labels isn’t a reliable drug difference.
Head-to-head comparisons can say more, but even those apply to groups, not you. How you respond also depends on your other medicines, your blood pressure, and your kidney and liver function. If you’ve had a bad experience with one ED tablet, that’s useful information for your prescriber, not proof that another will behave the same way. For the sildenafil side of the story, see sildenafil side effects.
Why Tadalafil Side Effects Happen
Knowing why a medicine causes certain effects makes them less mysterious. Some effects have a widely used explanation, and others are simply observed. We’ll separate the two, because the label lists effects without always explaining them.
One medicine, many tissues
Tadalafil is designed to relax smooth muscle in blood vessels of the penis. The same type of tissue lines blood vessels elsewhere, which is the usual explanation for several common effects.
Blood vessel effects: headache, flushing, congestion
The usual explanation is vessel widening beyond the penis. Widening in the face and skin could account for flushing, in the nose for stuffiness, and in the head for headache. This is a general pharmacology explanation. The label we reviewed lists these effects and their rates, but we didn’t find text that ties each one to a specific mechanism, so treat the explanation as plausible rather than proven for every case.
It also helps explain why blood pressure matters. Tadalafil can add to the blood pressure effect of other medicines that widen vessels, which is why nitrates are contraindicated and alpha blockers need care. We cover those combinations in a later section. Dizziness, which Mayo Clinic lists among oral ED medicine effects, can fit the same pattern.
Effects the label doesn’t explain well
Indigestion, back pain, and muscle aches are on the label’s common list, but the label reports them without a clear mechanism. That’s honest, and it’s worth saying plainly: we know these effects occurred more often on tadalafil than on placebo in trials, but not precisely why.
The distinction matters for two reasons. First, you shouldn’t assume a symptom is “just the medicine” if it doesn’t match the typical pattern described later in this article. Second, an unexplained effect isn’t automatically dangerous. The label describes back pain and muscle aches as generally starting 12 to 24 hours after a dose and resolving within about 48 hours, a timing pattern we’ll use in the section on everyday effects. If your symptom looks different, a clinician is the right person to sort it out.
Dose, timing, and a long half-life
Tadalafil stays in the body longer than some other ED tablets. That affects when effects appear, how long they last, and how long precautions apply.
The dose pattern in the data
In the as-needed table, several effects rose with dose. Headache went from 11% at 5 mg and 10 mg to 15% at 20 mg, and indigestion climbed from 4% to 8% to 10%. A higher dose doesn’t raise every effect equally, though: muscle aches went 1%, 4%, 3% across the three doses, not a clean line, and the small trial groups make fine differences hard to interpret.
This is one reason prescribers don’t simply start high. The labeling describes a starting dose and an allowed range, and the prescriber adjusts for how you respond and what else you take. Please don’t read the table as an instruction to raise or lower your own dose. For how labeled doses work, ask your prescriber.
A long half-life and steady state
The label reports a median time to peak blood level of about 2 hours and a mean half-life of 17.5 hours in healthy subjects. A half-life is the time it takes the amount of drug in the blood to fall by half, so most of the medicine takes a day or more to clear. With once-daily use, the label says steady state, meaning a stable level in the blood, is reached within about 5 days.
Why this matters for safety: any precaution tied to blood level, such as the nitrate warning, doesn’t switch off an hour after a dose. Timing and half-life are why this article treats precautions as lasting longer than one evening.
Everyday Side Effects and How to Handle Them
Most of what people notice after tadalafil is uncomfortable rather than dangerous. The practical goal is to recognize the usual pattern, keep a simple record, and know which changes are worth a phone call. None of this replaces your prescriber’s advice about your own situation.
Headache, flushing, stomach, and nose
These are the effects most likely to show up in the first hours after a dose. They tend to overlap, so they’re easier to understand together than one by one.
Headache and flushing
Headache led the label’s list of adverse reactions in the as-needed trials, and flushing, a warm, red feeling in the face or chest, was reported by 1% to 3% of men depending on dose. MedlinePlus advises telling your doctor if side effects are severe or don’t go away. The UK’s NHS says headaches usually fade after the first week of use and suggests resting, drinking fluids, and avoiding excess alcohol.
Ask a pharmacist before choosing a pain reliever, because your other medicines, your stomach, and your blood pressure all matter. A headache that’s sudden, severe, or unlike your usual ones isn’t a routine side effect to wait out. The label’s postmarketing list includes rarer events such as migraine and seizure, so unusual or intense symptoms deserve a call, or emergency help if they’re severe.
Indigestion, stuffy nose, and lightheadedness
Indigestion, also called dyspepsia or heartburn, was the second most common effect in the as-needed table, at 4% to 10% across doses. Nasal congestion was reported by 2% to 3% of men on tadalafil. Mayo Clinic’s list of oral ED medicine effects also includes dizziness.
For indigestion, tell your prescriber if it keeps recurring, particularly if you have a history of stomach ulcers. The label includes a caution for people with bleeding disorders or active peptic ulcers, and a clinician should know about that history before you start. Lightheadedness deserves extra care when you stand up quickly, drink alcohol, or take blood pressure medicines. If you feel faint, sit or lie down. Fainting, or dizziness with chest pain, is covered under urgent care below.
Back pain and muscle aches
This pair gets its own section because it surprises people the most. It often arrives the next day, when you’ve forgotten about the tablet, and it can look like a pulled muscle.
The 12-to-24-hour pattern
The label says back pain and myalgia generally begin 12 to 24 hours after a dose and typically resolve within 48 hours. Lilly’s patient information uses similar wording, though that document carries a 2017 revision date, so the current label is the better reference. In the as-needed table, back pain was 3% on placebo and 5% to 6% on the higher doses.
Marcus, 52, takes a tablet on Saturday evening as prescribed. By Sunday afternoon he has a dull ache across his lower back and thighs. He hasn’t lifted anything heavy and feels fine otherwise. He notes the time of the dose, when the ache started, and that it eased by Monday evening. Because it began roughly a day after the dose and faded within about two days, it matches the pattern the labeling describes. He doesn’t change anything on his own, but he mentions it at his next appointment and asks whether a different plan might suit him. Had the pain been severe, come with fever, numbness, or trouble urinating, or lasted well beyond two days, he’d have called the office sooner.
Hypothetical scenario for illustration only. It does not describe a real person and is not individualized medical advice.
When pain doesn’t fit the pattern
Back pain is common in daily life and has many causes unrelated to any medicine. That’s why the timing matters. Pain that is severe or lasts far beyond two days doesn’t match the typical label description, and a clinician should look at it rather than assume it’s the tablet.
The label describes severe back pain with tadalafil as rare. It also reports that a small fraction of men in the as-needed studies stopped the medicine because of it. For more on this specific symptom, see tadalafil and back pain. Call promptly for back pain with fever, numbness or weakness in the legs, trouble controlling urine or bowels, or any pain that worries you. Those signs point to causes that need evaluation whether or not you take tadalafil.
Warning Signs That Need Urgent Care
A small number of effects are rare but can cause lasting harm if you wait. Knowing them in advance lets you act quickly instead of searching online while a problem gets worse. Each of these appears in the Cialis labeling or in major patient resources.
Erection, heart, and allergic emergencies
Some warning signs involve the very thing the medicine treats, the heart that works harder during sex, or the body’s immune response. They share a rule: don’t wait to see if it passes.
An erection that lasts more than 4 hours
Priapism is an erection that doesn’t go away. The label says that patients with an erection lasting more than 4 hours, whether painful or not, should seek emergency medical attention, and that untreated priapism can cause irreversible damage to erectile tissue. The label advises caution in men predisposed to it, including those with sickle cell anemia, multiple myeloma, leukemia, or a physical deformity of the penis.
NIDDK lists this as a serious effect and says to call your health care professional right away. At 4 hours, don’t wait for a callback: go to an emergency department. Because tadalafil stays in the body a long time, an erection can outlast the evening, and it helps to know that in advance. Priapism is listed among postmarketing events; the label doesn’t give a rate we could verify.
An erection lasting more than 4 hours, sudden vision loss, sudden hearing loss, chest pain, fainting, or swelling of the face, lips, or throat needs urgent or emergency care. For vision or hearing changes, labeling and MedlinePlus say to stop the medicine and get medical attention promptly. For a very long erection or chest pain, go to an emergency department or call 911. Don’t drive yourself if you feel faint.
Chest pain, fainting, and allergic reactions
Sexual activity raises heart rate and blood pressure. The label says ED treatments should not be used in men for whom sexual activity is inadvisable for cardiovascular reasons, and that patients who have symptoms when starting sexual activity should refrain. MedlinePlus lists dizziness or chest pain among symptoms that need immediate attention. If you’ve been prescribed nitroglycerin, tell emergency responders exactly when you took tadalafil. The label says at least 48 hours should pass after the last dose before nitrate treatment is considered, because the combination can drop blood pressure sharply.
Allergic reactions are rare, but the label’s postmarketing list includes hives and severe skin reactions such as Stevens-Johnson syndrome. Get emergency help for hives with trouble breathing or swallowing, facial or throat swelling, or blistering or peeling skin.
| Warning sign | What it may signal | What sources say to do |
|---|---|---|
| Erection lasting more than 4 hours (painful or not) | Priapism, which can damage erectile tissue | Seek emergency care promptly |
| Sudden loss or decrease of vision in one or both eyes | Possible NAION (an optic nerve problem) or another eye condition | Stop the medicine and seek urgent care |
| Sudden hearing loss, with or without ringing or dizziness | Sudden hearing loss; relationship to the medicine can’t be determined | Stop the medicine and seek prompt care |
| Chest pain, fainting, or dizziness with nausea during sex | Heart strain or a blood pressure drop | Stop activity; get emergency help |
| Hives, facial or throat swelling, trouble breathing, peeling skin | Allergic or serious skin reaction | Seek emergency care |
Source note: FDA-approved Cialis labeling (DailyMed, revised 3/2026); MedlinePlus (revised 04/15/2023); NIDDK (reviewed October 2024); Mayo Clinic (January 21, 2026). This is a summary of published guidance, not medical advice for your situation. When in doubt, call emergency services.
Eyes and ears
Two rare problems involve the senses. In both, the key facts are the same: they are uncommon, the link to the medicine is not fully established, and speed of care matters.
Sudden vision loss
The label tells patients to stop PDE5 inhibitors and seek care for sudden vision loss in one or both eyes, which may signal NAION (non-arteritic anterior ischemic optic neuropathy, an interruption of blood flow to the optic nerve). Back in 2005, American Family Physician reported the FDA’s label update and said it was unclear whether the drugs caused the vision loss. Mayo Clinic says something similar about pre-existing conditions.
A 2022 JAMA Ophthalmology study, summarized by the American Academy of Ophthalmology, reported associations between PDE5 inhibitor use and some serious eye conditions, but association is not proof of cause, and the summary didn’t separate results by drug. Changes in color vision were rare in the label’s trials, under 0.1% of men. Blurred vision or a blue tint, which Mayo and Lilly describe, should still be reported. For more, see ED medication and vision changes.
Sudden hearing loss
The label advises stopping PDE5 inhibitors and seeking prompt medical attention for sudden decrease or loss of hearing, which may come with ringing in the ears or dizziness. It also says it isn’t possible to determine whether these events are related directly to the use of PDE5 inhibitors.
A 2007 HealthDay report on the FDA’s labeling action described 29 reported cases, most in one ear and about a third temporary. That’s a count of reports, not a rate, and it can’t show cause. Sudden hearing loss has many causes and is time-sensitive, so don’t wait to see if it improves. Tell the clinician exactly when it started and when you last took tadalafil.
Medicine Interactions and Health Conditions That Change Safety
The same tablet can be routine for one person and risky for another, depending on what else is in the medicine cabinet and what else is going on in the body. Many of the most serious tadalafil problems involve a combination rather than the drug alone, which is why your full medicine list matters so much.
Combinations that lower blood pressure
Tadalafil relaxes blood vessels, and so do several other drug classes. When effects stack, blood pressure can drop further than expected. Two combinations deserve the most attention.
Nitrates, poppers, and riociguat
The Cialis label contraindicates any form of organic nitrate, whether taken regularly or only now and then. That includes nitroglycerin tablets, sprays, and patches, and isosorbide products often prescribed for angina. Riociguat, a medicine for certain lung and pulmonary hypertension conditions, is also contraindicated. MedlinePlus adds that this applies to “poppers,” street products containing amyl or butyl nitrite. A contraindication means the combination should not be used, because it can cause a dangerous drop in blood pressure, with dizziness, fainting, heart attack, or stroke described in Lilly’s patient information.
Because tadalafil clears slowly, timing matters: the label says at least 48 hours should pass after the last dose before nitrate treatment is considered, under close medical supervision. ED medication and nitrates goes deeper on this topic.
Alpha blockers and blood pressure medicines
Alpha blockers relax muscle in the prostate and blood vessels and are used for BPH and sometimes for high blood pressure. The label notes that tadalafil can add to their blood-pressure-lowering effect and can cause symptomatic low blood pressure. For men treated for ED, it says patients should be stable on the alpha blocker before starting tadalafil and that the lowest dose should be used first. For BPH, it says the combination of tadalafil and alpha blockers is not recommended.
The label also reports small blood pressure effects in studies with several other blood pressure medicines. Taking a blood pressure medicine doesn’t automatically rule tadalafil out, but your prescriber needs to know which one, at what dose, and how steady your readings are. For more on that pairing, see tadalafil and alpha blockers.
Ravi, 61, takes tamsulosin for an enlarged prostate and recently began tadalafil for ED after a clinic visit where his prescriber reviewed his list. A few weeks later, he stands up quickly from the couch and feels dizzy and a little faint for a few seconds. The feeling passes, but it happens again the next day. Ravi doesn’t skip or double any doses. He writes down when he took each medicine, how long before the dizziness it was, and what his blood pressure readings were at home. Then he calls the prescriber’s office. Because the label describes additive blood pressure lowering with alpha blockers, the office wants to hear about it. If he had actually fainted or had chest pain, he’d have called emergency services instead of the office.
Hypothetical scenario for illustration only. It does not describe a real person and is not individualized medical advice.
Metabolism, organ function, and other conditions
The body breaks tadalafil down mainly with an enzyme called CYP3A4. Medicines that change that enzyme, or organs that clear the drug, can change how strong the dose effectively is.
CYP3A4 inhibitors and inducers
An inhibitor slows the enzyme and raises tadalafil levels; an inducer speeds it and lowers them. The label reports that ketoconazole, an antifungal, increased tadalafil exposure (measured by AUC, the total drug exposure over time) by 312% in an interaction study. Ritonavir, an HIV medicine, increased it by 124% at one dose studied. Rifampin, an antibiotic used for tuberculosis, lowered exposure by 88%.
Labeling sets lower limits for use with strong inhibitors, and your prescriber applies them; we’re not listing doses here, because they’re for the prescriber to set. Mayo Clinic names itraconazole, ketoconazole, and ritonavir as medicines that may not be safe or may not work with ED tablets. Because the details depend on dose and regimen, the practical step is to list every prescription, over-the-counter product, and supplement for your pharmacist.
| Category | Examples | What labeling says |
|---|---|---|
| Nitrates and riociguat | Nitroglycerin, isosorbide products, amyl or butyl nitrite “poppers,” riociguat | Contraindicated; sharp blood pressure drop |
| Alpha blockers | Tamsulosin, doxazosin, alfuzosin | Additive blood-pressure lowering; for BPH the combination is not recommended |
| Strong CYP3A4 inhibitors | Ketoconazole, itraconazole, ritonavir | Raise tadalafil exposure; lower limits apply |
| CYP3A4 inducers | Rifampin | Lowered exposure (88% in a study) and may reduce effect |
| Other PDE5 inhibitors | Sildenafil, vardenafil, avanafil | Combination not studied; not to be taken together |
| Kidney or liver disease | Reduced kidney clearance, Child-Pugh B or C | Dose limits; some uses not recommended |
Source note: FDA-approved Cialis labeling (DailyMed, revised 3/2026), Sections 4, 5, 7, and 8; MedlinePlus (revised 04/15/2023); Mayo Clinic (January 21, 2026). Not a complete list. Labeling describes categories and study results; your prescriber applies them to your doses and health history.
Kidney, liver, heart, and other conditions
For kidney function, the label sets lower dose limits and longer spacing when creatinine clearance, a measure of kidney filtering, is between 30 and 50 mL/min, and lower again below 30 mL/min or on dialysis. For liver disease, there are dose limits in mild or moderate impairment and the label doesn’t recommend use in severe impairment. Age alone doesn’t call for an adjustment, though the label notes some older men may be more sensitive.
Heart conditions deserve their own conversation. The label lists groups not studied in trials, including those with a heart attack in the previous 90 days or a stroke in the previous six months. The AUA guideline-guideline) notes that ED can be a risk marker for cardiovascular disease and describes cardiovascular risk assessment before treatment. Mention any heart, blood pressure, eye, blood cell, or penile history, because each appears in label or MedlinePlus lists of things to report.
Alcohol, Food, and Products That Change the Picture
Not every safety factor is a prescription. What you drink, what you eat, and what you buy online can all change how tadalafil feels and how safe it is, and some of the riskiest products don’t even say they contain a drug.
Alcohol and food
Daily habits are the easiest part of your safety picture to adjust, so it’s worth knowing which ones the sources actually address and which ones they don’t.
Alcohol
The label notes that both alcohol and tadalafil act as mild vasodilators, meaning they widen blood vessels. It states that substantial alcohol consumption (for example, five units or more) combined with tadalafil can increase orthostatic signs and symptoms, such as faster heart rate, lower standing blood pressure, and dizziness. It also reports that tadalafil and alcohol did not change each other’s blood levels, so the concern is the additive effect on blood vessels, not a change in how the drug is absorbed.
MedlinePlus states that large amounts make dizziness, headache, fast heartbeat, and low blood pressure more likely. “Substantial” is the key word, and the label doesn’t define a safe amount for every person. Your own tolerance, other medicines, and blood pressure matter. For a focused look, see tadalafil and alcohol.
Food and grapefruit
The label says tadalafil may be taken without regard to food, so a meal doesn’t change the way it does for some other ED tablets. Tadalafil and food covers that topic in more detail.
Grapefruit is less settled. MedlinePlus tells readers to talk to their doctor about eating grapefruit or drinking its juice while taking tadalafil. Grapefruit juice can affect CYP3A4, the same enzyme discussed earlier, which is the usual reasoning behind the caution. We didn’t find a labeled grapefruit dose rule, so ask your prescriber or pharmacist instead of guessing. See tadalafil and grapefruit for the narrower question.
Hidden-ingredient and online products
Unregulated products are a safety issue in their own right, because the main danger isn’t a side effect of a known drug. It’s an unknown amount of a drug, sometimes in combination with others, taken without any medical screening.
Supplements that may contain tadalafil
The FDA has repeatedly warned about “natural” sexual enhancement products that were found to contain undeclared drugs. A notification dated May 29, 2026 reported sildenafil and tadalafil in a supplement that didn’t list them on its label. The FDA warned that the hidden ingredients may interact with nitrates and lower blood pressure to dangerous levels, and that it cannot test every supplement for hidden ingredients.
An unlisted drug means an unknown dose or whether it’s stacking on top of a prescription. That’s how someone could end up with too much drug or an interaction they never saw coming. For the broader evidence picture, ask your pharmacist about any supplement. If you’ve had a bad reaction, the FDA notice points to its MedWatch program for reporting adverse events.
Ordering without an evaluation
NIDDK advises not ordering an ED medicine online before talking with a health care professional, and to tell your provider about all medicines, supplements, and alternative products. The reason isn’t bureaucratic. A prescriber can check your blood pressure, review nitrate or alpha blocker use, ask about eye and heart history, and choose a regimen. Without review, contraindications are easy to miss.
Pills shared by a friend or bought from an unverified seller carry the same problems, plus uncertain contents. If you want care without an in-person visit, that’s a decision about access, not safety shortcuts; a clinician or pharmacist can explain care routes and questions to ask.
Common Questions About Tadalafil Side Effects
These are the questions people most often ask after reading the label or noticing an effect. The answers stay close to the sources we opened, and where the sources are silent, we say so.
Duration and stopping
Two practical questions come up first: how long an effect might last, and whether it’s a reason to stop. The first has a fairly clear answer from labeling, while the second depends on which effect you mean.
How long do tadalafil side effects last?
It depends on the effect. Lilly’s patient information says most of the common effects usually go away within a few hours, while back pain and muscle aches typically start 12 to 24 hours after a dose and usually clear within about two days. The current label gives the same back pain and myalgia window, 12 to 24 hours to onset and resolution within about 48 hours.
Because tadalafil leaves the body slowly, with a mean half-life of 17.5 hours in healthy subjects, an effect can linger longer than expected. Headaches may ease with repeated use; the UK’s NHS says they usually fade after the first week. If an effect lasts longer than the pattern described here, gets worse, or is severe, call the prescriber.
Should I stop tadalafil if I notice a side effect?
For ordinary effects such as mild headache or a stuffy nose, call your prescriber instead of stopping on your own. NIDDK specifically advises not stopping any medicine on your own without talking to a health care professional. A prescriber may adjust the dose, change the regimen, or look at other causes.
There is an important exception in the labeling. For sudden vision loss or sudden hearing loss, the label and MedlinePlus say to stop the medicine and get medical attention promptly, and an erection lasting more than 4 hours needs emergency care. Chest pain, fainting, hives, or swelling of the face or throat also need emergency help rather than a wait-and-see approach. If you aren’t sure which category your symptom falls into, call the prescriber’s office or a pharmacist the same day.
Heart, dosing, and mix-ups
The last two questions involve situations where the cost of a mistake is higher: a heart condition, or taking more medicine than intended.
Is it safe to have sex while taking tadalafil if I have heart disease?
There isn’t a single answer, and that’s why the question belongs with a clinician. The label says ED treatments shouldn’t be used in men for whom sexual activity is inadvisable for cardiovascular reasons, and that men who have symptoms when starting sexual activity should refrain and get medical advice. Lilly’s patient information says to stop and get help for chest pain, dizziness, or nausea during sex.
The AUA guideline-guideline) describes the Princeton III framework, in which low-risk men may be treated without extra cardiovascular evaluation, while men with other cardiovascular conditions need cardiology input first. Which group you fall into is a judgment for your clinician, based on your history, medicines, and exercise tolerance. If you use nitrates, tadalafil is contraindicated.
What should I do if I took more tadalafil than prescribed?
Lilly’s patient information says to take no more than one tablet per day and, if you take too much, to call your healthcare provider or go to the emergency room right away. Don’t wait to see if symptoms develop, because the long half-life means effects such as low blood pressure or a prolonged erection could appear hours later.
Mixing tadalafil with another ED tablet is a related mistake. The label says safety and efficacy of combining it with other PDE5 inhibitors hasn’t been studied, and patients shouldn’t take it with other PDE5 inhibitors; see taking Viagra and Cialis together. A pharmacist can often tell you in minutes whether a double dose or mix-up needs emergency care, but if you feel faint, have chest pain, or develop a long erection, go to emergency care first.
Your Next Steps
Safety questions are easier to answer when you arrive with specifics. A short written record and a complete medicine list let a prescriber or pharmacist give you advice that fits your situation, instead of general reassurance.
Preparing for the conversation
Preparation doesn’t have to be elaborate. A few notes, collected before an appointment or phone call, cover most of what a clinician will ask.
What to write down about your symptoms
Note which effect you noticed, when you took it, when it began, how long it lasted. Add the dose and whether you take tadalafil as needed or daily, since the patterns differ. Include what else you took that day, including alcohol, and any home blood pressure readings if you have a cuff.
Record whether the effect fit the label’s typical pattern or didn’t, such as back pain on the day after a dose versus pain that was severe or lasted many days. Be honest about how it affected you, including whether it made you reluctant to use the medicine. That detail can lead to a better plan. Also note what you were doing, since heart-related symptoms during sex are a different situation than a headache hours later.
What to bring to the appointment
Bring a complete list of prescription medicines, over-the-counter products, and supplements, plus any products bought online or given to you by someone else. Include nitrates, alpha blockers, blood pressure medicines, antifungals, HIV medicines, and any “poppers” or recreational products; clinicians ask because of safety, not judgment.
Bring your health history too: heart, blood pressure, eye, kidney, liver, and blood cell conditions, previous long erections, and any sudden vision or hearing loss. A pharmacist can check your list against interactions at no extra visit cost in many cases, though policies vary. The table below organizes the items by purpose.
| What to note | Why it helps | What to bring up |
|---|---|---|
| Timing of the dose and the effect | Matches the label’s typical patterns, such as back pain 12 to 24 hours later | “It began about a day after my dose and lasted two days” |
| Every medicine and supplement | Catches nitrates, alpha blockers, and enzyme-affecting drugs | A written list, including products bought online |
| Alcohol on the same day | Alcohol and tadalafil both widen blood vessels | How much you had and whether you felt lightheaded |
| Heart, eye, ear, and kidney or liver history | These change which warnings apply | Past heart attack, stroke, vision loss, or hearing loss |
| Any urgent-sign symptom | Some need emergency care rather than a call | Long erection, sudden vision or hearing change, chest pain |
Source note: Original editorial checklist based on the FDA-approved Cialis labeling (DailyMed, revised 3/2026), MedlinePlus (revised 04/15/2023), and NIDDK (reviewed October 2024). A preparation tool, not a self-diagnosis guide. Your clinician decides what applies to you.
After the visit
Once you’ve talked with a clinician, the next steps are about follow-up and about keeping the information current as your health and medicines change.
Who to contact for what
For a quick medicine question, a pharmacist is often the fastest contact. For a pattern of effects, dose questions, or changes in other medicines, call the prescriber who manages your tadalafil. For emergency signs such as a long erection, sudden vision or hearing loss, chest pain, or an allergic reaction, go to emergency care.
If you aren’t sure which clinician to see for ED care in general, a primary care clinician is a common starting point. You can also report a suspected adverse event to the FDA’s MedWatch program, as the agency’s notices describe. Tell every new prescriber you take tadalafil, including dentists and surgeons, since MedlinePlus advises mentioning it before surgery.
Revisiting your options
Side effects don’t mean you’ve run out of choices. Your prescriber may consider a different dose, daily instead of as-needed use, another medicine, or a non-drug approach, depending on your health. For a view of how the labeled regimens differ, see daily vs. as-needed tadalafil; for a head-to-head picture, sildenafil vs. tadalafil sets out what matters.
If you want the big picture on causes, testing, and treatment, the erectile dysfunction overview is the place to start. Reassess whenever your medicines or health change, because a regimen that was safe a year ago may need a fresh look after a new blood pressure or prostate prescription.
Tadalafil side effects fall into three groups. Most are common, mild, and short-lived: headache, indigestion, flushing, a stuffy nose, and back or muscle aches that tend to arrive a day after a dose. A smaller group needs a call to your prescriber because of timing, severity, or a pattern that doesn’t fit. And a few rare events need urgent care without delay: an erection lasting more than 4 hours, sudden vision loss, sudden hearing loss, chest pain or fainting, and serious allergic reactions.
The biggest safety lever isn’t a single symptom. It’s a complete, up-to-date medicine list shared with your prescriber and pharmacist, because nitrates, riociguat, alpha blockers, blood pressure medicines, certain antifungals and HIV medicines, heavy drinking, and untested online products can change the risk. Labeling describes what happened in groups of men. It can’t predict your experience, so your own notes, timing, and history matter.
If you take tadalafil now, keep the urgent-care list handy and don’t change your dose on your own. If you’re considering it, bring your questions and your health history to a clinician who can match the plan to you.
Sources and further reading
- CIALIS (tadalafil) prescribing information: DailyMed , current FDA-approved labeling (revised 3/2026): adverse reaction tables, warnings, interactions
- Tadalafil: MedlinePlus Drug Information , plain-language side effects and precautions (revised 04/15/2023)
- Erectile dysfunction: in-depth: Mayo Clinic , oral ED medicine effects and warnings (January 21, 2026)
- Treatment for erectile dysfunction: NIDDK , serious effects and advice on online ordering (reviewed October 2024)
- Erectile Dysfunction: AUA Guideline: American Urological Association-guideline) , counseling on PDE5 inhibitors and cardiovascular risk (2018)
- FDA Advisories: Label Information Updated for Erectile Dysfunction Drugs: American Family Physician , historical report on sudden vision loss and NAION labeling (October 15, 2005)
- X10 Natural Enhancement Supplement may be harmful due to hidden drug ingredients: FDA , undeclared sildenafil and tadalafil (May 29, 2026)
Source links were checked on October 12, 2026. Guidance, drug labeling, prices, and availability can change, so confirm current details with an official source or your clinician.