Tadalafil Dosage: Daily vs As-Needed and How to Choose

Unlike most other PDE5 inhibitors, tadalafil can be taken in two fundamentally different ways. Understanding the distinction is key to getting the best results.

As-needed (on-demand) dosing:

• You take a single tablet before planned sexual activity
• Available strengths: 10 mg (starting dose) and 20 mg (maximum single dose)
• The BNF recommends taking the tablet at least 30 minutes before sexual activity
• Tadalafil has a long duration of action: up to 36 hours, which is why it is sometimes called "the weekend pill"
• Maximum frequency: one dose per day

Daily dosing:

• You take a low-dose tablet every day at the same time, regardless of when sexual activity is planned
• Available strengths: 2.5 mg (starting dose) and 5 mg
• After a period of steady-state dosing (usually 4 to 5 days), the medicine maintains a consistent background level in the body
• This removes the need to plan ahead and allows for greater spontaneity

Both approaches are equally effective when used correctly.

The choice depends on the frequency of sexual activity, personal preference, and any co-existing conditions such as benign prostatic hyperplasia (BPH), for which daily tadalafil is also licensed.

If you have sexual activity two or three times per month or less, as-needed dosing is usually the most practical option.

Starting dose: 10 mg

• Take one 10 mg tablet at least 30 minutes before sexual activity
• Some men find that it works faster than this; others may need up to 2 hours for full effect
• The effects last up to 36 hours, so a tablet taken on Friday evening may still be effective on Sunday morning
• Sexual stimulation is required for the medicine to work

Adjusting to 20 mg:

• If 10 mg does not produce a satisfactory response after several attempts, your prescriber may increase the dose to 20 mg
• The 20 mg dose should not be exceeded

Reducing to 5 mg as needed:

• In some cases (e.g. renal impairment, hepatic impairment, or concomitant use of CYP3A4 inhibitors), your prescriber may suggest a lower as-needed dose

Timing tips:

• Tadalafil can be taken with or without food
• Unlike sildenafil, a fatty meal does not significantly affect absorption
• Moderate alcohol intake is unlikely to interfere, but heavy drinking can reduce effectiveness and increase side effects

Daily tadalafil is an excellent choice for men who are sexually active more than twice a week, or who prefer not to plan around taking a tablet.

How daily dosing works:

• Take one tablet every day at approximately the same time
• Steady-state plasma levels are reached within about 5 days
• Once at steady state, the medicine is continuously active, and you can have sexual activity at any time without additional tablets

Starting dose: 2.5 mg daily

• Your prescriber will usually start with 2.5 mg daily
• After 4 to 8 weeks, the dose may be increased to 5 mg daily if the response is insufficient

5 mg daily for BPH:

• Tadalafil 5 mg once daily is also licensed for the treatment of benign prostatic hyperplasia (lower urinary tract symptoms)
• In men who have both erectile dysfunction and BPH, a single daily 5 mg tablet can address both conditions

Advantages of daily dosing:

• Greater spontaneity (no need to plan)
• Potentially fewer peak-related side effects, as the drug level is more consistent
• Dual benefit for men with co-existing BPH
• Simpler routine: take it with your morning or evening medicines

Your prescriber should re-evaluate the need for daily tadalafil periodically. If your circumstances change, switching to as-needed dosing may be appropriate.

Certain groups need dose adjustments or additional monitoring.

Older adults:

No dose adjustment is required solely on the basis of age.

However, older adults are more likely to have renal or hepatic impairment and to take interacting medicines, so the prescriber should take these factors into account.

Renal impairment:

• Mild to moderate: no adjustment needed for daily or as-needed dosing
• Severe (creatinine clearance below 30 mL/min): the as-needed starting dose should be reduced to 5 mg (maximum 10 mg not more than once every 48 hours). Daily dosing is not recommended in severe renal impairment

Hepatic impairment:

• Mild (Child-Pugh A): as-needed dose should not exceed 10 mg. Daily dosing may be used with caution
• Moderate to severe (Child-Pugh B or C): tadalafil should generally be avoided or used only under specialist supervision

Concomitant CYP3A4 inhibitors:

• Medicines such as ketoconazole, itraconazole, ritonavir and clarithromycin increase tadalafil exposure. The BNF advises a reduced maximum as-needed dose of 10 mg (not more than once every 72 hours) when these medicines are used regularly. For daily dosing, the maximum is 2.5 mg

Always disclose all your medicines, including over-the-counter products and herbal supplements, to your prescriber.

It is perfectly possible to switch between as-needed and daily tadalafil under your prescriber's guidance.

Switching from as-needed to daily:

• Stop taking the 10 mg or 20 mg tablets
• Begin taking 2.5 mg or 5 mg at the same time each day
• Allow 4 to 5 days to reach steady state before expecting full benefit
• You do not need to take an as-needed dose during the transition period

Switching from daily to as-needed:

• Stop daily tablets
• Wait at least 2 to 3 days for the medicine to clear sufficiently from your system before taking an as-needed dose (to avoid exceeding effective levels)
• Resume as-needed dosing with 10 mg

Reasons to switch include changes in sexual activity frequency, side effect profile, cost considerations, or the development of BPH symptoms that might benefit from daily dosing.

Discuss any planned change with your prescriber to ensure a smooth transition.

Tadalafil shares the same core safety considerations as other PDE5 inhibitors.

• Never combine with nitrates (e.g. GTN spray, isosorbide mononitrate). The combination can cause severe hypotension.
• Avoid concurrent use with other PDE5 inhibitors such as sildenafil or vardenafil.
• Seek urgent medical attention if you experience priapism (an erection lasting more than 4 hours), sudden vision loss (NAION) or sudden hearing loss.
• Cardiovascular fitness: erectile dysfunction medicines are only appropriate if sexual activity is considered safe for your heart. Men with recent myocardial infarction, unstable angina, uncontrolled hypertension or severe heart failure should not take tadalafil.

Common side effects of tadalafil include headache, back pain, myalgia, nasal congestion and dyspepsia.

Back pain and muscle aches are more characteristic of tadalafil than of sildenafil, likely related to PDE11 inhibition. These effects are usually mild and self-limiting.

Report any side effects to your GP or via the Yellow Card Scheme.