Spedra Dosage for Erectile Dysfunction: The Complete Guide

Spedra (avanafil) is a prescription medication used to treat erectile dysfunction and is licensed in the UK at three doses, 50mg, 100mg, and 200mg, with 100mg the usual starting point for most men. Which dose is right for you is confirmed during a clinical assessment, based on your individual response, tolerability, and any medicines you are already taking.

This guide brings together everything worth knowing about Spedra dosage, including what the trial evidence actually shows at each dose, and when a lower dose or extra caution is needed because of other medicines you take.

Getting dosage right matters more than it might first appear, the right dose for you balances a genuinely useful effect against side effects that remain manageable, and the evidence below shows this balance does not always follow the assumption that a higher number automatically means a better outcome.

Key things to know

• Spedra is licensed at three doses: 50mg, 100mg, and 200mg, with 100mg the usual starting point.
• Taken as needed, approximately 15-30 minutes before planned activity, and no more than once in 24 hours.
• Spedra remains fully prescription-only at every dose, it has never been reclassified for pharmacy sale.
• Certain medicines require a lower maximum dose or are contraindicated entirely, covered in detail below.
• Which dose is appropriate for you should be determined by your prescriber based on your response, tolerability and other medicines.

The Three Licensed Doses

Spedra tablets are available in 50mg, 100mg, and spedra 200mg strengths, each a separate, physically distinct tablet. 50mg is the lowest available strength and may be used when a lower dose is appropriate because of tolerability or individual response. 100mg is the standard starting dose for most men. 200mg is the highest licensed dose and may be considered if 100mg does not provide an adequate response and is well tolerated.

Each strength works through exactly the same mechanism, inhibiting the PDE5 enzyme to support the natural blood-flow response to sexual stimulation, dose affects concentration and therefore how strongly this effect is supported, not the underlying process itself. None of the three strengths works without stimulation, regardless of dose.

How the Right Dose Is Determined

Your starting dose and any subsequent adjustment should be based on individual effectiveness and tolerability, as confirmed through clinical assessment and, where appropriate, follow-up review. This is not necessarily a one-time decision; changes in your circumstances or other medicines you take may affect which dose remains appropriate. Spedra supports the body's natural response when appropriate stimulation is present.

Moving between doses, whether up to 200mg or down to 50mg, should always be confirmed by whoever is managing your treatment, this is not something to adjust based on a single occasion or general information.

The general principle behind this individualised approach is straightforward, how strongly any medicine affects a person depends on genuine, individual factors, including how quickly it is processed by the body and how sensitive someone is to its effects. Having three licensed strengths available allows a prescriber to match the dose to your response, rather than applying a single fixed amount to everyone regardless of how they individually respond.

Start Your Free Assessment

What the Evidence Shows by Dose

In a general-population clinical trial of 646 men, the proportion reporting a successful outcome was 41.3% at 50mg, 57.1% at 100mg, and 57.0% at 200mg, compared with 27.0% on placebo, a statistically significant difference at every dose. This is genuine, trial-based UK evidence, not an estimate.

A genuinely interesting, honest pattern in this data is that 100mg and 200mg produced almost identical rates in this trial, the meaningful jump in response came from 50mg to 100mg, not from 100mg to 200mg. This is useful context for understanding why 100mg is the standard starting dose, and why moving to 200mg is a considered decision rather than an automatic assumption that more is better.

It is worth being precise about what this trial evidence can and can not tell you. It reflects outcomes across a general population of 646 men, not a guarantee for any individual, your own response depends on the underlying cause of your erectile dysfunction and other personal factors, which is why a proper assessment considers your specific circumstances rather than applying this population-level figure directly to you. This evidence is also specific to avanafil, and it sits within the wider group of erectile dysfunction treatments that work in similar ways. NICE's evidence summary explicitly notes that no trial has directly compared avanafil's efficacy against sildenafil, tadalafil, or vardenafil head-to-head, so this data should not be read as ranking avanafil against other PDE-5 inhibitors as direct comparators in this trial, only as showing its own dose-response pattern.

Start Your Free Assessment

How to Take Spedra

Spedra is taken as needed, generally 15-30 minutes before it is needed, swallowed whole with water, and the duration of response varies between individuals. It can be taken with or without food, though a high-fat meal delays how quickly it is absorbed, delaying the time to peak concentration by around 1.25 hours and reducing peak levels by around 39% at 200mg, without significantly changing the total amount ultimately absorbed, so a high-fat meal may delay the onset of activity. Alcohol can lower blood pressure when taken with Spedra and may increase the likelihood of dizziness or fainting; it may also make it harder to achieve an erection. The maximum recommended frequency is once every 24 hours, regardless of dose.

Food can affect the timing of PDE5 inhibitors differently. For Spedra, a high-fat meal can delay absorption and the onset of activity compared with the fasted state, though taking Spedra in the fasted state avoids the food-related delay in absorption seen after a high-fat meal.

When Dose Adjustments Are Needed for Interactions

Certain other medications can change what Spedra dose is safe because of drug interactions involving the same liver enzyme pathway, CYP3A4, that clears avanafil from your body. This is a level of detail worth understanding clearly rather than assuming all interacting medicines are treated the same way.

Medicines including ketoconazole, ritonavir, atazanavir, clarithromycin, indinavir, itraconazole, nefazodone, nelfinavir, saquinavir, and telithromycin are contraindicated with Spedra entirely, combining them is not a dose question, it is a straightforward no. Nitrates are also contraindicated because they can lower your blood pressure severely.

A second group of medicines, including erythromycin, amprenavir, aprepitant, diltiazem, fluconazole, fosamprenavir, and verapamil, do not rule out Spedra entirely but do require a lower maximum dose, capped at 100mg, with at least 48 hours between doses. These moderate CYP3A4 inhibitors require both a lower maximum dose and lower frequency. This is exactly why disclosing your complete, current list of other medications during assessment matters, this level of interaction can only be properly checked with full information.

This two-tier system exists because these medicines slow down how quickly avanafil is cleared from your body to different degrees, a potent inhibitor can raise avanafil levels substantially, which is why combining it is avoided entirely rather than simply managed with a lower dose, while a moderate inhibitor's effect is significant enough to need a lower cap and longer spacing, but not severe enough to rule out the medicine altogether. Knowing which category a medicine falls into is not something to work out yourself, this is exactly what your prescriber checks during assessment. Alpha-blockers can also increase the risk of low blood pressure, so dose selection and timing may need individual assessment.

Start Your Free Assessment

Maximum Frequency and Dose Limits

200mg is the maximum licensed dose under standard circumstances, and once every 24 hours is the maximum frequency at any dose. Taking more than this is not a safe self-adjustment, if you are ever unsure whether you have taken more than intended. Contact a pharmacist, prescriber or NHS 111 for advice rather than taking another dose.

This once-daily maximum applies regardless of how the previous dose went, whether it worked well, worked partially, or did not seem to work at all, taking a second dose within the same 24-hour period is not an appropriate response in any of these scenarios, the correct step is always to wait and discuss the pattern at a review if it continues.

Dosage in Special Circumstances

• Severe hepatic impairment: Spedra is contraindicated; mild to moderate hepatic impairment requires treatment to start at the minimum effective dose.
• Certain cardiovascular conditions: may affect which dose, or whether Spedra at all, is appropriate.
• Alongside a moderate CYP3A4 inhibitor: capped at 100mg maximum, with 48 hours minimum between doses.
• Severe renal impairment: Spedra is contraindicated when creatinine clearance is below 30 mL/min
• Alongside a potent CYP3A4 inhibitor: contraindicated, not a dose question.

These circumstances share a common thread, they all change how avanafil behaves in your body compared with the general population the standard dosing guidance is based on. This is precisely why a full, honest medical history and medication list at assessment matters so much, standard dosing assumes a typical case, and a proper assessment is what identifies whether your circumstances fall outside that typical pattern.

Common Dosage Questions and Misconceptions

A common misconception is that 200mg simply works better than 100mg, the genuine trial evidence above shows this is not straightforwardly true, the two doses performed very similarly in the general-population trial. Another misconception is that a higher dose is a way to guarantee a result, individual response varies, and dose is only one factor among several, alongside timing, food, and the underlying cause of your erectile dysfunction; the appropriate dosage is individual, and if lower doses have been proven ineffective but tolerated, a clinician may consider a higher dose.

You should not split or combine Spedra tablets to create a different dose unless your prescriber or pharmacist specifically tells you to do so.

A further misconception worth addressing directly is the idea that taking Spedra more frequently than once every 24 hours, or taking an extra tablet if the first "did not seem to work", is a reasonable way to improve results. This is not a safe self-adjustment, and a single disappointing occasion is often better explained by timing, food, tiredness, or stress than by the dose itself being wrong, a genuine pattern across several attempts is what a review should look at, not a single occasion.

Start Your Free Assessment

How Spedra's Dosing Compares to Other PDE5 Inhibitors

Understanding how Spedra's dosing range sits alongside other licensed PDE5 inhibitors can help put its specific dose numbers into context, since strengths are not directly comparable across different medicines.

Do not take Spedra with other PDE5 inhibitors or other erectile dysfunction treatments at the same time, because the safety of these combinations has not been established and combining treatments may increase the risk of adverse effects.

Doses are not directly comparable milligram-for-milligram across different medicines, each has its own separately established dosing range, this table shows the general pattern rather than a like-for-like conversion.

Missed or Extra Doses

Since Spedra is taken as needed rather than on a fixed schedule, there is no missed dose in the usual sense. If you have already taken a dose, do not take another within the same 24-hour period. If you are ever unsure whether you have taken more than intended, contact 111 or your pharmacist rather than guessing.

This is a genuinely different pattern from a medicine taken every day regardless of need, where a missed dose can affect a steady level being maintained in your body. Spedra's as-needed use means there is no ongoing level to maintain between occasions, each time is essentially independent, worth understanding so missed-dose thinking from a different type of medicine is not mistakenly applied here.

What a Clinical Assessment Confirms

Your assessment considers your medical history, current medications, the fact that Spedra contains avanafil, any CYP3A4 interactions, nitrate use, herbal remedies and cardiovascular risk factors when determining the appropriate dose. If you have previously tried a PDE5 inhibitor, sharing your experience, including the dose and any side effects, genuinely helps inform the right starting point for you.

This is also the right place to raise any questions about how a specific dose might suit your circumstances, a proper assessment is a genuine, individualised conversation, not a generic form.

Ongoing treatment benefits from periodic review too, not just the initial assessment. If your circumstances change, a new medicine is started, your response to the current dose changes, or you simply have questions after using it for a while, a follow-up review is the appropriate way to reconsider your dose, rather than making any adjustment based on general information alone.

Red Flags Worth Knowing

• Prolonged erections lasting 4 hours or more are a serious side effect and need immediate medical attention, at any dose.
• Chest pain, dizziness, or fainting: seek urgent medical attention.
• Sudden vision or hearing changes: stop taking Spedra and seek prompt medical attention.
• Starting a new medicine without checking for interactions: tell your doctor or pharmacist about your Spedra treatment before starting new medicines.

Medical Disclaimer

This page provides general information about Spedra (avanafil) dosage based on UK licensing and clinical evidence. It is not a substitute for personalised medical advice. Your specific dose depends on an individual clinical assessment. Your prescriber will determine the appropriate treatment for you. Results vary between individuals. If you experience an erection lasting 4 hours or more, or chest pain, seek urgent medical attention.