Tadalafil Side Effects: Common and Serious Reactions
Tadalafil can cause side effects, although not everyone who takes it will experience them.
The most commonly reported reactions are headache, indigestion, back pain, muscle aches, pain in the arms or legs, facial flushing and nasal congestion. These are usually mild and temporary.
Most settle without treatment, but uncommon and rare serious effects can occur, including significant allergic reactions, chest pain, prolonged erections, sudden visual problems, sudden hearing loss, fainting and seizures.
Understanding the difference helps you manage mild reactions properly, recognise symptoms needing urgent help, and use treatment more safely.
Key things to know
- Common effects are usually mild, temporary, and often settle as treatment continues
- Some effects are dose-related, so a higher dose may be less well tolerated for some people
- Headaches with once-daily treatment are often reported during the first few weeks
- Chest pain, a four-hour erection, sudden vision or hearing loss and severe allergic symptoms need urgent attention
- Tadalafil must never be combined with nitrate medicines
- Suspected side effects can be reported through the MHRA Yellow Card Scheme
Why Tadalafil Causes Side Effects
Tadalafil belongs to the PDE5 inhibitor group. Its intended action involves increasing the effect of a messenger called cGMP, which relaxes smooth muscle and affects blood vessels.
Although that helps increase blood flow where it is wanted, tadalafil's effects are not completely restricted to erectile tissue. Blood vessel and smooth muscle effects elsewhere contribute to symptoms such as headache, facial flushing, nasal congestion and changes in blood pressure.
The safety picture also depends on why you are taking it. Tadalafil is used for erectile dysfunction, and in some cases for benign prostatic hyperplasia or, under specialist prescribing, pulmonary arterial hypertension.
Common Side Effects
- Headache
- Back pain
- Muscle aches
- Pain in the arms and legs
- Facial flushing
- Nasal congestion
- Indigestion
These do not necessarily mean tadalafil is unsuitable. Many are temporary and become less troublesome as treatment continues.
Persistent, severe or repeatedly troublesome symptoms should be discussed with a pharmacist or prescriber.
Headache
Headache is one of the most frequently reported effects, thought to be related partly to tadalafil's effects on blood vessels. Symptoms range from mild pressure or aching to something more troublesome.
With once-daily treatment, headaches are particularly common during the first 10 to 30 days, and some people find them less troublesome as treatment continues. That does not mean every headache will disappear.
If headache is severe, recurrent or interfering with treatment, a dose review may be appropriate rather than continuing indefinitely with the same regimen.
Back Pain and Muscle Aches
Back pain is among the reactions most commonly associated with tadalafil, alongside headache, indigestion and muscle pain. It is generally mild or moderate, and usually temporary.
The exact mechanism is not fully established, although it may relate to tadalafil's effects on phosphodiesterase enzymes in tissues outside the erectile system.
Muscle aches, medically called myalgia, are also common, and pain can occur in the arms or legs.
Seek medical advice if pain is severe, prolonged or progressively worsening, or if it comes with weakness, numbness or other unexpected neurological symptoms. New severe leg pain, significant swelling, or symptoms affecting only one leg should not automatically be attributed to tadalafil, since other causes may need assessment.
Indigestion and Reflux
Indigestion is one of the most frequently reported effects. Less common digestive symptoms include stomach pain, nausea, vomiting and acid reflux.
Reflux can occur, although it is less common than indigestion. Anyone who repeatedly develops it after taking tadalafil may benefit from reviewing the dose and other contributing factors with a healthcare professional.
Persistent digestive symptoms are worth discussing rather than repeatedly self-treating without reviewing the regimen.
Flushing and Nasal Congestion
Facial flushing may feel like warmth, redness or temporary heat affecting the face and sometimes the upper body. It occurs because tadalafil influences blood vessel tone, and is generally temporary.
Nasal congestion results partly from changes in blood vessels within nasal tissues. Although generally harmless, it can become troublesome for people taking tadalafil every day.
Blood Pressure and Cardiovascular Effects
Dizziness and Low Blood Pressure
Tadalafil can lower blood pressure, because it causes blood vessel relaxation. Symptoms can include dizziness, light-headedness, weakness, blurred vision and faintness.
Dizziness may be more noticeable when tadalafil is combined with alcohol, blood pressure medicines, alpha blockers or anything else that lowers blood pressure.
If tadalafil makes you dizzy or affects your vision, avoid driving or operating machinery until you feel well again. Severe dizziness or fainting requires medical assessment rather than being assumed an ordinary side effect.
High blood pressure has also been reported, although less commonly. A single raised reading after taking tadalafil does not prove the medicine caused it, and anyone with uncontrolled hypertension needs assessment before treatment regardless.
Palpitations and Chest Pain
A pounding heartbeat or faster heart rate can occur.
Chest pain is uncommon but important. If it develops after taking tadalafil, seek immediate medical assistance.
Do not independently use a nitrate medicine such as glyceryl trinitrate, because tadalafil and nitrates together can cause a dangerous fall in blood pressure. Tell emergency healthcare professionals that you have taken tadalafil, and when your most recent dose was.
Seek urgent assessment if palpitations occur alongside chest pain, severe breathlessness, fainting or significant weakness.
Heart Attack and Stroke
Heart attacks and strokes have been reported in men taking tadalafil. Many reported cases involved people who already had cardiovascular risk factors or established heart disease, so an event occurring after tadalafil does not automatically prove tadalafil caused it.
Erectile dysfunction itself can be associated with cardiovascular risk, which is why suitability is assessed beforehand.
Possible heart attack or stroke symptoms require emergency care regardless of the suspected cause.
Serious but Less Common Effects
Vision
Visual effects can include blurred vision, eye discomfort and changes in vision. Rare but serious eye problems have also been reported.
A mild temporary disturbance and sudden significant vision loss are not the same problem. Sudden, severe, dimmed or substantially reduced vision requires urgent medical attention. Do not wait for it to resolve.
Hearing
Serious hearing problems are rare. Possible symptoms include ringing in the ears, reduced hearing, sudden hearing loss, and dizziness alongside hearing changes.
Sudden hearing loss is considerably more concerning than isolated mild tinnitus, and should be assessed urgently, particularly when accompanied by tinnitus or dizziness.
Prolonged Erection
Priapism, a prolonged and potentially painful erection, is rare.
An erection lasting four hours or longer requires immediate medical treatment, because prolonged pressure can damage penile tissue and may cause permanent erectile problems. It is not evidence that tadalafil is working particularly well.
This is worth distinguishing from the 36-hour figure. That refers to the period during which tadalafil may support an erectile response when stimulation occurs. It does not mean an erection should remain continuously present.
Allergic Reactions
Allergic reactions can include rash, itching, swelling, swelling of the face, lips or tongue, and difficulty breathing or swallowing.
A severe reaction can be life-threatening. Severe breathing difficulty, throat swelling or collapse requires emergency care.
Other Reported Effects
Breathlessness can occur. Seek urgent assessment if it is severe or sudden, or comes with chest pain, facial or throat swelling, fainting or severe weakness.
Fainting is uncommon, and may relate to blood pressure changes or an underlying cardiovascular problem. It should be assessed rather than assumed ordinary.
Seizures have been reported rarely, and require urgent assessment regardless of whether tadalafil is thought responsible.
Temporary memory disturbances have been reported rarely. New significant confusion or memory loss needs assessment, since many other causes are possible.
Nosebleeds can occur. An occasional minor one may not indicate a problem, but recurrent or heavy bleeding warrants advice.
Blood in the urine has been reported, but should not automatically be attributed to tadalafil, since it can have many other causes.
Swelling of the hands, feet or ankles can occur. More serious facial, lip, tongue or throat swelling may indicate an allergic reaction, and sudden swelling with breathing or swallowing difficulty is an emergency.
Fatigue can occur, although persistent tiredness should not be attributed entirely to tadalafil without considering other medicines, sleep and underlying conditions.
Dose and Duration
Does a Higher Dose Cause More Side Effects?
Some effects are dose-related. Headache, indigestion, back pain and muscle pain can become more frequent as the dose increases, so 20mg may be less well tolerated than a lower dose for some people.
That does not mean everyone taking 20mg experiences more adverse effects. The dose should be selected according to both effectiveness and tolerability.
Daily 5mg Compared With 20mg On Demand
The same active medicine is involved, but the exposure pattern differs. 20mg is a higher individual dose, while daily treatment is designed to maintain exposure over time.
For anyone who develops troublesome effects on either regimen, treatment should be reviewed rather than doses switched independently.
How Long Side Effects Last
There is no single duration. Tadalafil is long acting, so mild symptoms can sometimes persist longer than with shorter-acting options.
Duration depends on the dose, whether treatment is daily or on demand, individual metabolism, kidney and liver function, and any interacting medicines.
Serious symptoms should not be managed by waiting for tadalafil to leave the body. Chest pain, sudden major vision changes or a prolonged erection require immediate assessment.
Long-Term Use
Tadalafil's safety profile has been evaluated in large clinical studies involving thousands of patients, covering both on-demand and once-daily treatment.
Long-term daily treatment should still be reviewed periodically, particularly if your health conditions change, your kidney or liver function changes, you start new medicines, side effects become troublesome, or tadalafil is no longer providing adequate benefit.
Can Side Effects Be Permanent?
Most are temporary.
Rare serious complications involving vision, hearing or prolonged erections can potentially cause lasting problems if treatment is delayed. Untreated priapism, for example, can damage penile tissue and lead to persistent erectile difficulties.
Sudden major vision or hearing changes should therefore be treated as urgent rather than monitored at home.
What Makes Side Effects Worse
Alcohol
Drinking substantial amounts while taking tadalafil can increase the risk of dizziness, a drop in blood pressure and light-headedness on standing. Heavy drinking also makes erectile function less reliable in its own right.
Other Medicines
Tadalafil exposure and blood pressure effects can change when other medicines are present. Important groups include:
- Nitrate medicines
- Riociguat
- Alpha blockers
- Blood pressure medicines
- Strong CYP3A4 inhibitors
- Other PDE5 inhibitors
A complete medication review matters before treatment starts, and temporary medicines such as antibiotics should be disclosed too.
Grapefruit juice may increase tadalafil levels, so mention it to your prescriber or pharmacist if you consume it regularly.
Why Nitrates Are Dangerous
Tadalafil must not be combined with nitrate medicines. Both affect the same pathway and can produce significant blood pressure lowering together.
That can lead to severe dizziness, fainting, dangerously low blood pressure and cardiovascular complications.
If you develop chest pain after taking tadalafil, seek emergency help and tell healthcare professionals when you last took it. Do not take a nitrate yourself unless specifically directed to.
Other ED Tablets
Do not independently combine tadalafil with sildenafil, vardenafil or avanafil.
Combining PDE5 inhibitors can increase headache, flushing, dizziness, low blood pressure and the risk of a prolonged erection.
If tadalafil does not provide sufficient benefit, the dose and strategy should be medically reviewed rather than another medicine added.
Taking Too Much
Excess tadalafil increases exposure and adverse-effect risk. Do not exceed one tablet in 24 hours unless specifically prescribed otherwise.
Do not take another tablet because the first seems slow, because treatment appears inadequate, or because you want the effect to last longer.
Tadalafil can remain active for up to approximately 36 hours after an on-demand dose, so additional doses create substantial overlapping exposure.
What to Do About Side Effects
It depends on the symptom.
For mild common effects such as headache, mild flushing, nasal congestion or mild indigestion, read the patient information leaflet and speak to a healthcare professional if symptoms are persistent or bothersome.
Stop tadalafil and seek urgent medical attention for:
- Chest pain. Do not use nitrate medicines
- An erection lasting four hours or longer
- Sudden loss or major reduction of vision
- Sudden hearing loss
- Severe allergic symptoms, including breathing difficulty, tongue or throat swelling, or collapse
- Fainting or seizures
Reporting Side Effects
Suspected side effects can be reported through the MHRA Yellow Card Scheme.
A Yellow Card report does not prove that tadalafil caused the reaction. The scheme helps UK regulators monitor suspected adverse effects once medicines are in wider use.
