Sildenafil Dosage Explained - ZipHealth

If you’ve been researching erectile dysfunction treatments and their doses, you’ll be familiar with popular prescription drugs like Viagra and Sildenafil. Read on for your expert guide to Sildenafil dosage.

What is sildenafil

Sildenafil is the non-branded (generic) version of Viagra – both medications for erectile dysfunction contain the same active ingredient sildenafil citrate and are taken orally in tablet form. The main difference between the two is the price – here at ZipHealth for example sildenafil costs up to 95% less than branded Viagra.

How sildenafil works

Sildenafil treats erectile dysfunction by selectively inhibiting an enzyme called phosphodiesterase (PDE) type 5. Inhibiting this enzyme allows the smooth muscle at the base of the penis to relax, improving blood flow and making it easier to achieve and maintain a harder erection during sexual stimulation. It's important to note that sildenafil and other erectile dysfunction drugs require sexual stimulation to be effective; they won’t produce an erection on their own.

Available strengths of sildenafil

Medications for erectile dysfunction come in different strengths and doses. Sildenafil is taken as an oral tablet in 25 mg, 50 mg, and 100 mg doses, and should not be taken more than once a day. [1] A dose of 50mg is usually recommended, or the lower dose of 25mg if you’ve experienced side effects, have an existing health condition such as low blood pressure or are over the age of 65. The highest dose of 100mg is recommended if you've already tried the 50mg dose and it hasn't been effective.

How long does it take for sildenafil to work? 

Sildenafil takes approximately one hour to reach its maximum effect – though it usually continues to work for about four to five hours. This doesn't mean you'll have an erection the entire time. Instead, it means that during these four to five hours, sildenafil will help you get an erection when you’re sexually stimulated. 

Sildenafil medication may be taken 30 minutes to 4 hours before sexual intercourse. [2]

Dosage for erectile dysfunction (ED)

Typical starting dose for ED

The recommended starting dose for most adult men taking PDE5 inhibitors like Sildenafil is 50 mg. But as mentioned above, there are instances where a lower or higher dose will be recommended based on your personal circumstances. [3] 

Dose adjustments for effectiveness and tolerability

Most adverse effects of Sildenafil are mild, dose related and typically end once treatment is stopped. The most common side effects are headaches, facial flushing, dizziness, nasal congestion, blurred vision and palpitations. Less common adverse events include back pain, flu-like symptoms, rash, vomiting, diarrhea, chest pain and arrhythmia (irregular heartbeat or rhythm). [2] If you’re experiencing any of these less common adverse effects or are worried that they’re worsening, get in touch with your ZipHealth clinical team or healthcare provider as a matter of urgency. 

Interactions with medications and foods

Sildenafil works better on an empty or nearly empty stomach because heavy or high-fat meals can result in reduced absorption. [2] You can drink alcohol while taking Sildenafil – but doing so may make it more difficult to get an erection. [2]

If you think you could benefit from taking Sildenafil, Viagra or any of our other ED medications (Cialis and Tadalafil or generic Cialis are also available), find out what treatment is suitable for you on our website here. Your prescription pills will be sent to your door (as quickly as the next day) in discreet packaging.

1. Langtry HD, Markham A. Sildenafil: a review of its use in erectile dysfunction. Drugs [Internet]. 1999 Jun 1;57(6):967–89. Available from: https://pubmed.ncbi.nlm.nih.gov/10400408/‌

2. Hatzimouratidis K. Sildenafil in the treatment of erectile dysfunction: an overview of the clinical evidence. Clinical Interventions in Aging [Internet]. 2006 Dec 1;1(4):403–14. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2699643/

3. Smith BP, Babos M. Sildenafil [Internet]. PubMed. Treasure Island (FL): StatPearls Publishing; 2020. Available from: https://www.ncbi.nlm.nih.gov/books/NBK558978/ 

4. Zinner N. ORIGINAL RESEARCH—ED PHARMACOTHERAPY: Do Food and Dose Timing Affect the Efficacy of Sildenafil? A Randomized Placebo‐Controlled Study. The Journal of Sexual Medicine. 2007 Jan;4(1):137–44.