Supplements and Saquinavir.
Saquinavir, sold under the brand names Invirase, Fortovase, is classified under "hiv protease inhibitor" in the BNF.
Saquinavir (UK brand names Invirase, Fortovase) sits in the Distil medication database. The BNF classifies it under "hiv protease inhibitor". This means it sits outside the high-volume therapeutic classes (statins, PPIs, ACE inhibitors, SSRIs) where supplement-interaction surfaces are densely studied, and the published evidence base for specific supplement pairs is correspondingly thinner. Where interactions are documented in the Distil database, they are listed below with their clinical-reference citation; where pairs have not been explicitly assessed, the missing-item form at the bottom of the page routes them into our next curation pass. Anyone combining Saquinavir with a regular supplement stack benefits from explicit GP or pharmacist awareness rather than assuming no interaction exists by default.
Below are the 2 documented pairs we have explicitly assessed against Saquinavir in the Distil database: 1 red and 1 amber. The pairs cluster around 2 mechanisms: CYP3A4 induction and P-glycoprotein interaction. Every call is cited to either a clinical reference (PMID) or the British National Formulary. Anything not on this list is either still to be assessed or beyond our database scope. The checker beneath surfaces assessments by supplement, and the missing-item form at the bottom of the page routes any uncatalogued supplement into our next curation pass.
Documented interactions
CYP3A4 induction
St John's Wort speeds up how the body clears HIV protease inhibitors like saquinavir, which can drop the drug level too low to control the virus and let HIV become resistant. This is a serious interaction and these medicines should not be combined. If you take saquinavir, do not start St John's Wort, and if you already take both, tell your HIV team before changing anything.
P-glycoprotein interaction
Garlic supplements can lower the level of saquinavir in the blood, which may make it less effective at controlling HIV when saquinavir is used as the only protease inhibitor. In a study, garlic cut saquinavir levels by about half. If you take saquinavir, discuss garlic supplements with your HIV team rather than starting them on your own. Normal culinary garlic is a smaller concern than concentrated supplements.
What this list does not say. Pairs not flagged here are not implicitly safe. They are either not yet in our database, or fall outside our inclusion scope (food-supplement interactions only; for drug-drug interactions, the BNF is authoritative). Use the checker below to surface any supplement, and submit a missing item if you take something we have not catalogued.
How we grade severity, choose what's in scope, and what we exclude.
Every call on this page is reasoned. We publish the full rubric for severity tiers, the medication inclusion logic, the evidence grades we accept, and what we deliberately leave out. About three thousand words. Worth reading once if you use this tool more than occasionally.
Read the full methodologyWant this reasoning across everything you take?
This page checks the pairs you enter. A personalised Distil report applies the same graded, cited reasoning to your whole stack: your goals, conditions, medications, diet, and the compounds worth adding or dropping. The interactions check is one section of it. You can read a real one in full before you decide.
See a real sample reportSomething missing?
If a supplement or medication you take isn't in our autocomplete, tell us. We go through what people flag every week and add what's missing.