Viagra drug interactions: a practical overview
Drug interactions are the single biggest cause of preventable medication problems. Viagra (Sildenafil Citrate) interacts to varying degrees with several classes of medication and with a smaller list of foods. This page summarises the practically important ones at 25mg, 50mg, 100mg, framed for a real-world prescription review rather than an exhaustive PDF list.
High-priority interactions for Viagra
For Sildenafil Citrate, the most clinically relevant interactions are typically with strong CYP3A4 inhibitors and inducers, with cardiovascular medications (notably nitrates for several Erectile Dysfunction (ED) agents), with central nervous system depressants, and with medications affecting blood pressure or heart rate. During sexual stimulation, nitric oxide is released in the corpus cavernosum and activates an enzyme that produces cyclic GMP.
Working with the pharmacist
A pharmacist review of all current medications is the practical safeguard against unintended interactions with Viagra. According to the prescribing information for Sildenafil Citrate, the full medication list — prescription, OTC, supplements and recreational substances — should be reviewed before starting and at every dose change at 25mg, 50mg, 100mg.
Frequently asked questions
What's the most important Viagra interaction to know? ▾
For most Erectile Dysfunction (ED) medications, the highest-priority interaction is with nitrate medications used for chest pain — this combination is often a hard contraindication. After that, strong CYP3A4 inhibitors (some antifungals, macrolides) are the next concern at routine 25mg, 50mg, 100mg doses.
Do I need to tell the pharmacist about supplements? ▾
Yes. Supplements and herbal products can interact with Viagra in ways that prescription drug-drug interaction databases miss. The pharmacist needs the complete picture — including supplements like St John's Wort, grapefruit-containing products and high-dose vitamins — to flag risks at 25mg, 50mg, 100mg.
More on Viagra
- With alcoholViagra and alcohol — is it safe to drink?
- With foodShould Viagra be taken with food?
- Side effectsViagra side effects: common, rare and warning signs
- Dosage guideViagra dosage guide: how much to take and when
- OnsetHow fast does Viagra start working?
- DurationHow long does Viagra last?
The information on this website is provided for reference and educational purposes only. It does not replace consultation with a qualified healthcare professional.