Tadalafil side effects: A complete guide 

DoktorABC editorial team

Accurate, up-to-date health information written by our editorial team and reviewed by UK-registered prescribers.

The most common side effects of tadalafil

The most commonly reported side effects in patients taking tadalafil for erectile dysfunction or benign prostatic hyperplasia were headache, indigestion, back pain, and muscle aches, with incidences increasing with higher doses. The side effects reported were transient and generally mild or moderate. 

Headache

Headache is the most frequently reported side effect of tadalafil across all doses and dosing regimens. The majority of headaches reported with once-daily tadalafil are experienced within the first 10 to 30 days of starting treatment, and most men find they reduce significantly or resolve entirely with continued use. Staying well hydrated before and after taking tadalafil can help reduce headache severity. 

Back pain and muscle aches

Back pain and muscle aches are more commonly associated with tadalafil than with sildenafil, and represent one of the more notable distinguishing features of the tadalafil side effect profile. They are thought to be related to tadalafil's inhibition of PDE11, an enzyme found in skeletal muscle. These side effects are generally mild to moderate, typically appearing 12 to 24 hours after taking the medicine and resolving within 48 hours.

Indigestion and nasal congestion

Indigestion, heartburn, and nasal stuffiness are common across all PDE5 inhibitors and are related to the vasodilatory mechanism. They are generally mild and resolve as the medicine clears the body. Taking tadalafil with or after a light meal can help reduce indigestion.

Flushing and dizziness

Mild flushing and dizziness are direct results of increased blood flow from vasodilation. They are more pronounced at higher doses and in the first few hours after taking the medicine. Sitting or lying down if dizziness occurs, and avoiding alcohol, reduces the risk.

Less common and rare side effects

The following side effects occur in a smaller proportion of men but require greater awareness because of their potential severity.

Visual disturbances

Uncommon visual changes associated with tadalafil include blurred vision, altered colour perception, and increased light sensitivity. These are generally mild and temporary, resolving as the medicine clears the body. Unlike sildenafil, tadalafil has lower selectivity for PDE6 in the retina, so visual side effects are somewhat less frequently reported.

Priapism

A prolonged erection lasting more than four hours is a medical emergency. Without prompt treatment, priapism can cause permanent damage to erectile tissue. If you have an erection lasting longer than four hours, seek emergency medical help immediately, regardless of whether it is painful.

Sudden hearing loss

Rare cases of sudden decrease or loss of hearing, sometimes accompanied by ringing in the ears or dizziness, have been reported with tadalafil in post-marketing data. Stop taking tadalafil and seek medical help promptly if this occurs.

Tadalafil and blood pressure

Tadalafil causes a mild and transient reduction in blood pressure as a result of its vasodilatory mechanism. For most men, this reduction is modest and well tolerated. However, in certain situations the blood pressure-lowering effect can become clinically significant.

The most important interaction is with nitrate medicines. Tadalafil is absolutely contraindicated alongside nitrates of any kind, including glyceryl trinitrate (GTN) spray, isosorbide mononitrate, and isosorbide dinitrate. The combination can cause a severe and potentially life-threatening drop in blood pressure.

Alpha-blocker medicines, often prescribed for an enlarged prostate or high blood pressure, can also interact with tadalafil to produce an additive blood pressure-lowering effect. This does not mean the combination is automatically unsafe, but it requires careful prescriber assessment, and a lower starting dose of tadalafil is typically recommended in this context.

Men with pre-existing low blood pressure (below 90/50 mmHg) should not take tadalafil. Men with well-controlled high blood pressure can generally use tadalafil safely under prescriber supervision, but a full cardiovascular assessment is required before starting.

Long-term side effects: What the evidence says

Tadalafil has been in clinical use for over 20 years, and its long-term safety profile is well characterised. For men using tadalafil on demand at 10 mg or 20 mg, the intermittent nature of use means long-term systemic exposure is limited.

For men using daily tadalafil at 5 mg, long-term use appears well tolerated in clinical studies. The side effect profile with daily dosing is broadly consistent with on-demand dosing, though headaches and back pain at the daily dose tend to reduce significantly after the first few weeks as the body adjusts.

There is no clinical evidence of organ toxicity, dependency, or cumulative harm from long-term tadalafil use at licensed doses. As with any long-term prescription treatment, periodic review with your prescriber is recommended to assess ongoing suitability, any changes in health status or concurrent medications, and whether the current dose remains appropriate.

Side effects by dose: 5 mg daily vs 10 mg and 20 mg on demand

The side effect profile of tadalafil varies between the daily low-dose and on-demand higher-dose regimens in two important ways.

Daily 5 mg: Side effect incidences increase with increasing dose of tadalafil. At the daily 5 mg dose, side effects are generally less pronounced than at the 10 mg or 20 mg on-demand doses. Headaches are most common in the first 10 to 30 days and typically reduce with continued use. Back pain and muscle aches are similarly less prominent at this lower dose. 

On-demand 10 mg and 20 mg: Higher doses produce a more pronounced peak blood level, which correlates with a higher incidence and intensity of side effects in the hours following the dose. This is most notable for headache, flushing, and back pain. The side effects are time-limited and resolve as the medicine is metabolised, though given tadalafil's long half-life of approximately 17.5 hours, some effects may persist longer than with sildenafil.

Drug interactions that worsen side effects

Several medicines can increase the risk or severity of tadalafil side effects by affecting how the drug is processed or by producing additive effects.

Nitrates: Absolutely contraindicated. The combination produces a severe and potentially dangerous drop in blood pressure.

Alpha-blockers: Used for enlarged prostate or high blood pressure. Can produce an additive blood pressure-lowering effect. A lower starting dose of tadalafil and careful prescriber monitoring is required.

Antihypertensive medicines: Blood pressure-lowering medicines can add to tadalafil's modest hypotensive effect. This is generally manageable but requires prescriber assessment before starting.

CYP3A4 inhibitors: Medicines that inhibit the CYP3A4 enzyme, including certain antifungals (ketoconazole, itraconazole), some HIV medicines (ritonavir), and the antibiotic clarithromycin, can significantly increase blood levels of tadalafil, amplifying both its effects and side effects. A dose reduction may be required if these medicines are prescribed concurrently.

Alcohol: Alcohol and tadalafil both lower blood pressure, and the combination increases the risk of dizziness, flushing, and headache. Modest alcohol consumption is unlikely to cause a serious problem for most men, but heavy drinking alongside tadalafil is not advisable. See our guide on tadalafil and alcohol for more detail.

When to stop taking tadalafil and seek medical advice

Most men who take tadalafil will not experience anything more serious than the mild, temporary side effects described above. However, it is important to know which symptoms warrant a conversation with your prescriber and which require immediate emergency attention. Contact your prescriber if:

• Side effects are persistent, worsening, or significantly affecting your daily life
• You experience any visual changes beyond mild temporary disturbances
• You have an erection lasting more than two hours
• You are prescribed a new medicine that may interact with tadalafil
• You experience chest pain, shortness of breath, or palpitations during or after sexual activity

Stop taking tadalafil and seek emergency help immediately if you experience:

• A prolonged erection lasting more than four hours
• Sudden loss or significant change in vision in one or both eyes
• Sudden decrease or loss of hearing
• Signs of a severe allergic reaction: swelling of the face, lips, tongue or throat, difficulty breathing, severe skin reaction
• Severe chest pain or a feeling of collapse

Report any suspected side effects to the MHRA via the Yellow Card scheme at yellowcard.mhra.gov.uk.

How to minimise tadalafil side effects

For most men, tadalafil side effects are mild enough to manage without stopping treatment. A few practical adjustments to timing, diet, and lifestyle can make a meaningful difference to tolerability, particularly in the first few weeks when side effects tend to be most noticeable. 

• Stay hydrated: Adequate hydration before and after taking tadalafil reduces headache severity for most men
• Take with or after a light meal: This can reduce indigestion, though unlike sildenafil, food does not significantly affect how quickly tadalafil works
• Limit alcohol: Keep consumption modest on the same occasion as taking tadalafil, particularly on-demand doses
• Start at the lowest effective dose: Beginning at 10 mg rather than 20 mg allows you to assess tolerability before escalating
• Consider daily dosing: For men who find on-demand 20 mg side effects difficult to manage, daily 5 mg may produce a more comfortable profile with comparable effectiveness
• Allow time: Many side effects, particularly headache and back pain with daily dosing, reduce significantly after the first few weeks as the body adjusts

Final thoughts

Tadalafil is a well-tolerated treatment for the majority of men who use it at recommended doses. The most common side effects are mild, temporary, and often reduce with continued use, particularly on the daily low-dose regimen. Knowing what to expect, and understanding the difference between a manageable common reaction and a symptom that requires urgent attention, puts you in the best position to use tadalafil safely and effectively.

If side effects are affecting your experience or confidence in the treatment, a conversation with your prescriber is always the right next step. There are options available, whether that involves a dose adjustment, a change in dosing schedule, or a switch to an alternative medicine.

FAQ

The DoktorABC medical advisory board

Dr. Roland Ruiken

Medical advisor, Norway

Dr. Viktor Simunovic

Medical advisor, Croatia

To the medical advisory board