Tadalafil 5mg: Uses, Dosage and Side Effects
Tadalafil 5mg is a low-dose, long-acting PDE5 inhibitor tablet used in adult men to treat erectile dysfunction and urinary symptoms caused by benign prostatic hyperplasia. It is usually prescribed as a once-daily medicine.
For men who want a prescription treatment that fits a daily routine rather than on-demand dosing, it is the standard licensed daily dose.
This guide explains how tadalafil 5mg is used, how the daily dose differs from the 10mg and 20mg on-demand tablets, and what to know about timing, side effects, precautions and interactions.
Key things to know
- 5mg is the standard once-daily dose, for erectile dysfunction, benign prostatic hyperplasia, or both
- Tadalafil has a half-life of approximately 17.5 hours, and reaches steady state within about five days of daily dosing
- Food does not meaningfully affect absorption, so it can be taken with or without meals
- It still requires sexual stimulation. Daily dosing does not produce a continuous erection
- Do not take it more than once per day
- It must not be combined with nitrates or riociguat
What It Is and What It Treats
Tadalafil 5mg is a film-coated tablet containing 5 milligrams of tadalafil, which belongs to a group of medicines called phosphodiesterase type 5 inhibitors.
It has two licensed indications in adult men: erectile dysfunction, and the signs and symptoms of benign prostatic hyperplasia.
The 5mg strength matters because it can be used as a once-daily medicine, rather than only before anticipated activity.
For Erectile Dysfunction
Tadalafil helps improve the ability to achieve and maintain an erection when appropriate stimulation occurs, by supporting relaxation of blood vessels within erectile tissue and allowing increased blood flow.
It does not produce an erection automatically. Sexual stimulation is still required.
A 5mg once-daily regimen may suit men who anticipate needing treatment frequently, such as at least twice a week, depending on clinical judgement and preference.
For Benign Prostatic Hyperplasia
Tadalafil 5mg is also licensed to treat urinary symptoms associated with benign prostatic hyperplasia, sometimes called benign prostate enlargement.
Symptoms can include:
- Difficulty starting urination
- Feeling that the bladder has not completely emptied
- Needing to urinate more frequently
- Waking during the night to urinate
Tadalafil helps relax smooth muscle in and around the prostate and bladder, which may improve those symptoms. It is not a treatment for prostate cancer.
Patient information states that improvement can begin as early as one to two weeks after starting treatment.
For Both Conditions Together
One distinctive use of tadalafil 5mg is that the same once-daily dose can be prescribed for men who have both erectile dysfunction and urinary symptoms from benign prostatic hyperplasia.
UK prescribing information states that for men being treated for both, the recommended dose remains 5mg once daily at approximately the same time each day.
European guidance also recognises tadalafil 5mg as the PDE5 inhibitor licensed for men with lower urinary tract symptoms, with or without erectile dysfunction.
Dosage
For daily treatment of erectile dysfunction, benign prostatic hyperplasia, or both, the dose is 5mg once daily, taken at approximately the same time each day.
Do not take tadalafil more than once per day. Use it exactly as prescribed, and ask for a review if the current dose is not giving the response you expected.
Why Take It at the Same Time?
UK prescribing information recommends taking the daily dose at approximately the same time each day, which helps maintain consistent concentrations.
That does not mean the exact same minute. A regular routine simply makes daily treatment easier to follow.
Morning or Evening?
Neither is inherently better. Pharmacokinetic studies show no clinically relevant difference in absorption between morning and evening dosing.
Choose a time that is easy to remember. If you routinely take it after breakfast, continue with that. If evening suits your routine better, that is equally appropriate.
Is 5mg Better Than 10mg?
Neither is automatically better. They serve different treatment patterns.
5mg is generally used as a once-daily regimen, while 10mg is the standard starting dose for on-demand use, with adjustment to 20mg where appropriate.
If you need treatment only occasionally, an on-demand dose may make more sense. If you prefer continuous coverage, 5mg daily may suit you better.
Can It Be Reduced to 2.5mg?
For once-daily erectile dysfunction treatment, yes. UK prescribing information states that 5mg can be reduced to 2.5mg once daily based on individual tolerability, which is primarily relevant where 5mg causes adverse effects.
For benign prostatic hyperplasia the situation differs. Product information states that the effectiveness of 2.5mg has not been demonstrated, so someone unable to tolerate 5mg should generally be considered for an alternative treatment rather than assuming 2.5mg provides the same urinary benefit.
If You Forget a Dose
NHS guidance says to take the forgotten dose when you remember, unless it is nearly time for the next scheduled dose. If the next dose is close, skip the forgotten one.
Do not take two doses together to compensate. The patient leaflet gives the same instruction: do not double dose, and do not take tadalafil more than once per day.
Taking More Than Prescribed
If your prescription is for 5mg daily, do not independently take additional tadalafil.
Do not take another tablet later the same day because the first seemed ineffective, because you forgot you had taken one, or because you want a stronger response. Extra dosing increases exposure and side effect risk.
10mg and 20mg tablets have authorised uses for on-demand treatment, but that does not make adding them to a daily 5mg regimen appropriate.
NHS guidance states that taking an extra dose can be dangerous, and recommends seeking urgent advice if too much has been taken.
How It Works and How Long It Lasts
Tadalafil inhibits the enzyme PDE5.
During stimulation, nitric oxide causes levels of a messenger called cGMP to increase, which relaxes smooth muscle and helps blood flow increase within erectile tissue. PDE5 normally breaks cGMP down, so inhibiting it allows the natural response to remain active for longer.
For urinary symptoms, tadalafil also affects smooth muscle within the prostate, bladder and urinary tract. European guidance notes that PDE5 inhibition reduces smooth muscle tone in these tissues, although the complete mechanism behind the symptom improvement is not fully established.
It Does Not Cause an Automatic Erection
Tadalafil requires appropriate stimulation to improve erectile function, and authorised medicine information states this explicitly.
Taking it every day does not mean an erection should occur continuously or spontaneously.
How Long It Takes to Work
Daily tadalafil should be understood differently from an on-demand tablet.
For on-demand tadalafil, effectiveness may begin from around 30 minutes after a dose. Daily 5mg treatment is instead intended to provide ongoing exposure, rather than requiring each dose to be timed before activity.
How Long It Takes to Build Up
Tadalafil reaches steady-state plasma concentrations within approximately five days of once-daily dosing.
Steady state means the amount entering the body through each dose becomes broadly balanced with the amount being eliminated.
That is why the effects of daily tadalafil should not be judged from the first tablet. Some men respond earlier, but consistent dosing provides a more stable level after several days.
Half-Life and Duration
Tadalafil has a mean half-life of approximately 17.5 hours in healthy adults, which is one reason it suits once-daily use and distinguishes it from shorter-acting PDE5 inhibitors.
A 17.5-hour half-life does not mean an erection lasts that long. It means tadalafil leaves the body gradually and continues to contribute to exposure for an extended period.
The UK patient leaflet states that once-daily tadalafil can support an erectile response, when stimulation occurs, at different times during the 24-hour period. The tablet does not need to be closely linked to a particular anticipated time.
What About the 36-Hour Window?
The well-known up-to-36-hour response window is primarily associated with on-demand dosing. European guidance reports that tadalafil's effectiveness window can extend from approximately 30 minutes after a dose to as long as 36 hours.
With 5mg daily treatment, the more useful concept is continuous steady exposure, rather than measuring a new 36-hour window after every tablet.
The Practical Benefits of Daily Dosing
- Daily treatment rather than planning every dose
- Sustained exposure to the medicine
- Less connection between tablet timing and anticipated activity
- Suitable for frequent treatment
- Treats erectile dysfunction and urinary symptoms simultaneously in appropriate men
- Minimal effect from food on absorption
European guidance describes 5mg once-daily tadalafil as an alternative to on-demand treatment for people who prefer less planned dosing, or anticipate frequent use.
Is 5mg Strong Enough?
For appropriately selected men, yes. European guidelines state that tadalafil 5mg once daily is effective and generally well tolerated across men with varying severity of erectile dysfunction.
Individual response still varies. Someone who does not respond adequately should not independently take additional tadalafil or combine it with another treatment. Treatment should be reviewed instead.
Food, Alcohol and Grapefruit
Tadalafil can be taken with or without food. Pharmacokinetic research shows that the rate and overall amount absorbed are not meaningfully influenced by meals, including high-fat meals.
That distinguishes tadalafil from some other PDE5 inhibitors whose onset can be delayed by food, and it means you do not need to coordinate your daily dose with a particular meal.
Alcohol
Alcohol requires caution. Both alcohol and tadalafil can lower blood pressure.
NHS guidance states that drinking alcohol with tadalafil can increase the risk of low blood pressure, dizziness or light-headedness, and that excessive alcohol can make erectile function less reliable in its own right.
Patient information similarly advises avoiding excessive drinking, because of the risk of dizziness when standing.
Grapefruit
Grapefruit juice can potentially increase tadalafil exposure through effects on the CYP3A4 enzyme pathway. UK medicine information advises caution, and the NHS advises avoiding grapefruit juice while taking tadalafil.
Side Effects
UK patient information lists the following as common, meaning they may affect up to 1 in 10 people:
- Headache
- Back pain
- Muscle aches
- Pain in the arms or legs
- Facial flushing
- Blocked nose
- Indigestion
Prescribing information notes that the most commonly reported reactions in studies were headache, indigestion, back pain and muscle pain, and that these were generally temporary and mild to moderate.
Headache and Back Pain
Headache is among the most commonly reported effects, and may be more noticeable early in treatment. With once-daily dosing, prescribing information notes that many headaches occur during the first 10 to 30 days.
Back pain is also recognised as common, reported in approximately 6.5% of tadalafil users in European guideline summary data. It is usually temporary, but persistent or severe symptoms should be assessed.
Muscle pain, and pain affecting the arms or legs, are also listed among common effects. Facial flushing and nasal congestion result from tadalafil's action on blood vessels.
Uncommon Effects
UK patient information lists uncommon effects including:
- Dizziness
- Stomach pain, nausea, vomiting or reflux
- Blurred vision or eye pain
- Breathlessness
- Blood in urine
- Prolonged erections
- Palpitations or increased heart rate
- High or low blood pressure
- Nosebleeds
- Tinnitus
- Swelling of the hands, feet or ankles
- Tiredness
These affect fewer people than the common reactions, but may still need medical advice depending on severity.
Serious Reactions
Serious reactions are uncommon or rare, but worth recognising. Seek urgent medical attention for:
- Chest pain
- A prolonged erection lasting four hours or longer
- Sudden loss or major reduction of vision
- Sudden hearing loss
- Significant allergic symptoms
Rare cardiovascular events including heart attack and stroke have been reported, particularly in men who already had cardiovascular risk factors.
Priapism, an abnormally prolonged and sometimes painful erection, is rare. Prescribing information states that an erection lasting four hours or more requires immediate medical assistance, because untreated priapism can damage penile tissue and potentially cause permanent loss of erectile function.
Vision. Blurred vision and eye pain are uncommon. Rare serious events including non-arteritic anterior ischaemic optic neuropathy, a condition affecting the optic nerve, and retinal vascular problems have been reported. Sudden loss or substantial reduction of vision requires urgent attention.
Hearing. Sudden hearing loss has been reported. Prescribing information advises stopping tadalafil and seeking prompt medical attention if a sudden decrease or loss of hearing occurs.
Who Should Not Take It
UK prescribing information lists contraindications including use in people who:
- Take nitrate medicines
- Take riociguat
- Have certain serious cardiovascular conditions
- Have very low blood pressure
- Have uncontrolled high blood pressure
- Recently had a heart attack
- Recently had a stroke
- Previously lost vision from non-arteritic anterior ischaemic optic neuropathy
Clinical suitability should be assessed before treatment starts.
Nitrates and Riociguat
Tadalafil must not be used with organic nitrate medicines, including nitrate treatment used for angina. The combination can produce potentially dangerous blood pressure lowering, because both influence the same pathway.
If chest pain develops after taking tadalafil, seek urgent medical care rather than self-administering a nitrate.
Riociguat is also contraindicated, for the same reason, because of the potential for symptomatic low blood pressure.
Blood Pressure Medicines and Alpha Blockers
Tadalafil can produce additional blood pressure lowering alongside antihypertensive medicines. European guidance notes that the average additional decrease is usually small, although people with poorly controlled blood pressure or certain combinations may be more susceptible.
Alpha blockers, used for high blood pressure and for urinary symptoms, require particular caution. Combining them with tadalafil can increase vasodilating effects and potentially cause dizziness or low blood pressure.
European guidance does recognise tadalafil 5mg as an option in selected men with lower urinary tract symptoms, including some taking alpha blockers, but treatment should be individually assessed.
Antibiotics and Other Interactions
Tadalafil is mainly metabolised through CYP3A4, and some medicines increase its concentrations, including certain antibiotics and antifungals.
Examples requiring consideration include erythromycin, clarithromycin, ketoconazole and itraconazole. Other medicines, such as rifampicin, may reduce tadalafil exposure.
Always give your prescriber an up-to-date list of both regular and temporary medicines.
Other ED Medicines
Do not independently combine tadalafil with another PDE5 inhibitor. Prescribing information states that the safety and effectiveness of such combinations have not been established.
That includes combining tadalafil with sildenafil, vardenafil or avanafil without specialist direction.
Specific Groups
Kidney Problems
For mild to moderate kidney impairment, routine dose adjustment is generally not required.
For severe kidney impairment, once-daily tadalafil at 2.5mg or 5mg is not recommended for either condition. Exposure can be substantially increased, and dialysis contributes very little to removal.
Liver Problems
Once-daily treatment has not been adequately evaluated in people with liver impairment.
If it is considered, UK information recommends an individual assessment of the potential benefits and risks.
Older Men
Routine dose adjustment is not required solely because someone is older.
However, kidney function, cardiovascular health and other medicines become increasingly important with age. Some daily studies for benign prostatic hyperplasia found dizziness and diarrhoea more frequently in patients over 75.
Men With Diabetes
Dose adjustment is not required solely because someone has diabetes.
Diabetes is itself an important contributor to erectile dysfunction and to cardiovascular risk, so the broader health assessment remains relevant.
Longer-Term Treatment
There is no universal fixed duration. Daily tadalafil can continue while it remains clinically appropriate and useful, and authorised information says the appropriateness of continuing should be reassessed periodically.
Tadalafil treats symptoms. It should not prevent assessment for other causes of urinary problems.
Stopping
Tadalafil is not usually tapered when stopped. However, stopping may allow the symptoms it was controlling to return. Discuss any planned change with your prescriber.
Does It Shrink the Prostate?
No. Tadalafil primarily improves urinary symptoms rather than acting as a prostate-shrinking medicine.
European guidance notes that PDE5 inhibitors improve symptom scores and quality of life, but generally do not significantly improve maximum urinary flow rate, and that there is limited information showing an effect on prostate size or long-term disease progression.
That distinguishes tadalafil from some other treatments for benign prostatic hyperplasia.
Is It the Only PDE5 Inhibitor Licensed for Urinary Symptoms?
European guidance states that tadalafil 5mg once daily is currently the PDE5 inhibitor licensed for treatment of male lower urinary tract symptoms.
That is an important distinction from PDE5 inhibitors used only for erectile dysfunction.
A Note on Spelling
Tedalafil, tadafil and taladafil are common misspellings. The correct generic name is tadalafil.
When searching online or checking packaging, using the correct spelling reduces the risk of confusing the medicine with unrelated or unverified products.
The Key Takeaway
Tadalafil 5mg is a once-daily treatment for erectile dysfunction, benign prostatic hyperplasia, or both together. It is a specific daily regimen rather than simply a lower-strength tablet to use whenever needed.
Its relatively long pharmacokinetic profile is what makes daily dosing possible, with a half-life of approximately 17.5 hours and steady state reached within about five days.
For erectile dysfunction it improves the normal blood-flow response but still requires stimulation. For urinary symptoms, improvement may begin within one to two weeks.
Use it exactly as prescribed, no more than once per day, and have ongoing treatment reviewed periodically to confirm the dose remains appropriate.
