Tadalafil, the active ingredient in Cialis, is a widely used treatment for erectile dysfunction (ED), known for its relatively long lasting effects. But because tadalafil can remain in the body for an extended period, understanding how much you can safely take within 24 hours is important. Taking more than the prescribed dose does not necessarily improve erectile function and may increase the risk of side effects. So, what is the maximum dose of tadalafil in 24 hours, and does the limit differ between daily and as needed use?
Here you will get to know the recommended dosage limits, how the two dosing options differ, and why staying within the prescribed dose matters for safe and effective treatment.
Depending on Your Dosing Plan, The Limit Is Different
There are two ways that tadalafil can be used to treat erectile dysfunction, and the limits are correspondingly different for each use:
Dosing Approach | Maximum Dose in 24 Hours | How It's Taken |
As-needed | 10 mg or 20 mg — one dose only | A single prescribed dose, taken no more than once in any 24 hours, shortly before anticipated sexual activity — not on a fixed schedule. |
Daily (continuous) | 5mg (or 2.5mg if reduced for tolerability) | Taken once a day at roughly the same time, regardless of whether sexual activity is planned. |
These two dosing programs are not meant to be used together. You should consult your doctor. Your doctor will prescribe one approach or the other, not both at once.
These dose limits assume normal kidney and liver function. If you have severe kidney impairment, the maximum as needed dose is reduced to 10mg and daily dosing is not recommended. If you have mild to moderate liver impairment, then the recommended dose is 10 mg. There are no available data for individual doses above 10 mg in patients with hepatic impairment, so higher on-demand doses are not used, and on-demand use requires an individual benefit–risk assessment by your doctor. Daily dosing in liver impairment also needs assessment by your doctor, who will recommend a lower dose or a different treatment approach altogether. Daily tadalafil is not recommended in severe hepatic impairment.
Never Combine Tadalafil With Nitrates
Tadalafil must not be taken together with nitrate medicines in any form, including glyceryl trinitrate (GTN), whether used for angina or chest pain, or with recreational nitrites such as "poppers", regardless of the tadalafil dose taken. This combination can cause a sudden, dangerous drop in blood pressure and is not made safer by staying within the usual dosing limits. Riociguat, a medicine used to treat pulmonary hypertension, is also contraindicated with tadalafil. Always tell your doctor about every medicine, supplement, or recreational drug you take before starting tadalafil.
If you have chest pain after taking tadalafil, go to hospital immediately - call an ambulance or ask for an emergency ambulance. Do not try to relieve the pain by taking GTN or other nitrate medicines yourself, because this could cause a dangerous fall in blood pressure. Inform the ambulance driver and hospital staff that you have taken tadalafil and when.
Actual How-To of As-Needed Dosage:
For a man who chooses to take tadalafil on an as-needed basis, a typical starting dose is 10 mg, taken before sexual intercourse, as a single dose — no more than once in any 24 hours.
Your dose can be increased up to the maximum prescribed on-demand dose of 20 mg if well tolerated and effective; to be taken as a single dose in any 24-hour period. Strengths for Australia are 10 mg and 20 mg - there isn't a 5 mg strength of on-demand dose. If you experience side effects at 10 mg which are poorly tolerated, your doctor will advise you on the most appropriate next step in your treatment, which might involve an alternative approach to on-demand dosing.
Daily Dosing: What You Actually Need to Know
Daily tadalafil is truly a different strategy; as opposed to having the correct time you will take a tadalafil dose before sexual contact. The standard starting dose for daily use is 5 mg, taken at roughly the same time each day. Depending on how well you tolerate it, your doctor may reduce this to 2.5 mg.
Why the 24 Hour Limit and Why It Is Particularly Important for Tadalafil
Tadalafil's most distinguishing characteristic among PDE5 inhibitors lies in its relatively long half-life (approximately 17.5 hours). This compares to approximately 4 hours for Sildenafil (Viagra). Because of this, the drug's clinical effects can last up to 36 hours after a single dose, meaning a man can be responsive to sexual stimulation well beyond the same day the person took it. This extended window of effect — not the half-life figure alone — is what earned tadalafil its "weekend pill" nickname.
What Happens if You Exceed the Recommended Dose of Tadalafil?
One may experience the following side effects if the recommended dose of tadalafil is exceeded:
- Headache, flushing & nasal congestion - these are the more common side effects and are more likely and more severe at higher concentrations.
- Low blood pressure (hypotension) - this risk is most severe, and can be life-threatening, when tadalafil is combined with nitrate medicines (including GTN) or recreational nitrites ("poppers"). This combination must be avoided completely at any dose, not just avoided at high doses. Alcohol and blood-pressure-lowering medicines can also add to this risk.
- Priapism - An erection in excess of 4 hours is a dangerous side effect and requires emergency intervention to avoid permanent tissue damage to be avoided.
If you take more than your prescribed dose of tadalafil accidentally, then it is important to contact the Poisons Information Centre on 13 11 26 without wasting a single sec. Even if you feel well and have no symptoms yet, it is impirtant to contact 13 11 26. Don’t wait to see whether side effects develop, then you will seek advice. If you experience an erection that lasts longer than 4 hours, treat this as a medical emergency and seek immediate treatment. If you delay seeking immediate treatment, it can lead to permanent damage.
Some medicines can also affect the safety of tadalafil for you. Strong CYP3A4 inhibitors — such as ketoconazole or ritonavir- can slow the rate at which your body clears tadalafil.
If you are prescribed one of these medicines, it is important to consult your doctor. Your doctor will review your tadalafil dose individually; this may involve reducing the daily dose. The right adjustment depends on your individual circumstances, so it is advised not to change your tadalafil dose yourself. Always seek medical advice if you are taking other prescription medicines.
Speak With Your Doctor About Your Tadalafil Dose
If you are unsure whether your current tadalafil dose is right for you or it is working for you, it is important to speak with your doctor or pharmacist. Your doctor will review your health history, any other medicines you are taking, and your treatment goals, and confirm the dosing approach that is appropriate and safe for you.
Frequently Asked Questions for Maximum Dose of Tadalafil in 24 Hours:
What is the max dosage of tadalafil per 24-hour period?
That depends on which of the tadalafil treatment programs you're using. The maximum is one prescribed dose of 10 mg or 20 mg, taken no more than once in any 24 hours. Daily dosing uses tadalafil; if you are using that, then the maximum daily tadalafil dose is 5 mg in 24 hours (or 2.5 mg if reduced for tolerability). These two dosing programs are not meant to be used together.
Can I take tadalafil once every 24 hours using the 20mg dose?
If prescribed 20 mg for on-demand use, take no more than one dose in 24 hours. This is a maximum frequency, not a recommendation to take 20 mg every day. Continuous daily treatment uses 5 mg, sometimes reduced to 2.5 mg. Do not combine the regimens.
What will happen if I accidentally take more tadalafil than the prescribed dosage?
A higher dosage won't work better than an established prescription; it may simply result in negative symptoms, including headache, flushing, decreased blood pressure, backache, or, in rare cases, prolonged erection that needs medical attention (Priapism). If this happens, contact the Poisons Information Centre on 13 11 26 immediately, even if you feel well. An erection lasting more than 4 hours requires emergency medical treatment.
Why does tadalafil have a lower daily maximum than as-needed maximum?
The use of tadalafil daily is designed to maintain relatively consistent, but low, levels in your blood because tadalafil has a long half-life of ~17.5 hours, whereas taking it on an as-required basis will deliver a relatively large single dose for use for sexual activity, which is why the on-demand maximum (20 mg) is higher than the daily maximum.
Can I change from taking tadalafil on an 'as required' basis to taking it daily?
Yes, but you need to do this on a doctor's advice rather than your own, so that you do not overexpose your body to the drug within 24 hours between the two different dosing regimens.
Can I take tadalafil with nitrate medicines?
No. Tadalafil must never be combined with nitrate medicines, such as GTN, or with recreational nitrites (“poppers”), regardless of the tadalafil dose taken. This combination of tadalafil with nitrate medicines can cause a dangerous drop in blood pressure. Riociguat is also contraindicated with tadalafil. If you develop chest pain after taking tadalafil, seek urgent medical help and do not take GTN or other nitrates yourself — tell paramedics or treating clinicians when you last took tadalafil. Always consult your doctor about all the medicines you take, including recreational drugs and over-the-counter, before starting tadalafil.
