Antiretroviral therapy (ART) has transformed HIV into a manageable chronic condition, but its success hinges on strict adherence and awareness of potential interactions. Many substances can alter how these life-saving drugs work, either by reducing their effectiveness—which can lead to drug resistance—or by increasing their concentration to toxic levels [1.4.1, 1.3.3]. Communicating openly with your healthcare provider about everything you take, including prescriptions, over-the-counter (OTC) remedies, and supplements, is the most critical step in managing your treatment safely.
Prescription and Over-the-Counter (OTC) Medications
Many common medications can interact with ART. These interactions often happen because both the antiretroviral (ARV) and the other drug are processed by the same enzymes in the body, primarily the cytochrome P450 (CYP) system, especially CYP3A4 [1.4.2].
Acid-Reducing Medications Some ARVs, like atazanavir and rilpivirine, require an acidic environment in the stomach to be absorbed properly [1.5.2, 1.2.3]. Medications that reduce stomach acid can significantly lower the absorption of these ARVs, making them less effective.
- Proton Pump Inhibitors (PPIs): Examples include omeprazole and esomeprazole. Co-administration with rilpivirine is generally not recommended, and with atazanavir, it requires careful dose timing [1.3.3].
- H2 Antagonists: Examples include famotidine. These also require careful scheduling, taken several hours apart from the ARV dose [1.2.1, 1.3.6].
- Antacids: Products containing aluminum, magnesium, or calcium (like Tums, Maalox) can bind to certain ARVs, particularly integrase strand transfer inhibitors (INSTIs), and prevent their absorption [1.5.2, 1.6.2]. It is often recommended to take INSTIs at least 2 hours before or 6 hours after these antacids [1.2.5].
Statins for Cholesterol Some statins, such as simvastatin and lovastatin, are strongly contraindicated with protease inhibitors (PIs) and cobicistat-boosted regimens. This combination can dangerously increase statin levels, raising the risk of severe muscle weakness or kidney failure [1.3.3]. Other statins, like atorvastatin and rosuvastatin, may be used but often require dose adjustments and careful monitoring [1.3.3].
Other Key Prescription Drug Interactions
- Anticoagulants (Blood Thinners): Drugs like apixaban and rivaroxaban can have significant interactions with boosted ART regimens, potentially leading to toxicity or reduced effectiveness. Co-administration is often not recommended [1.3.1].
- Corticosteroids: Inhaled and nasal steroids like fluticasone can build up to harmful levels when taken with ritonavir or cobicistat, leading to conditions like Cushing's syndrome [1.5.3].
- Antiseizure Medications: Some, like carbamazepine, can lower ARV levels, while some ARVs can affect seizure medication levels [1.4.6].
Herbal Supplements and Foods
Natural does not always mean safe, especially when combined with ART. Many people use herbal remedies without realizing the potential for serious interactions [1.6.1].
St. John's Wort This herbal supplement, often used for depression, is strictly contraindicated with many ARVs, particularly PIs and non-nucleoside reverse transcriptase inhibitors (NNRTIs) [1.4.6, 1.6.1]. St. John's wort induces CYP3A4 enzymes, which speeds up the metabolism of these ARVs. This can cause drug levels to fall dramatically, leading to treatment failure and the development of viral resistance [1.4.1, 1.4.2]. The effect can persist for up to two weeks after stopping the herb [1.4.5].
Garlic Supplements While garlic in food is generally safe, high-dose garlic supplements can reduce the concentration of some PIs, like saquinavir, by over 50% [1.6.7, 1.6.1]. This is thought to be due to the induction of intestinal P-glycoprotein, which affects drug absorption [1.6.1].
Grapefruit Juice Grapefruit and Seville oranges contain compounds that inhibit CYP3A4, the opposite effect of St. John's Wort. This can increase the levels of certain ARVs (like PIs and maraviroc), potentially leading to toxicity and more side effects [1.2.2, 1.6.1].
Mineral Supplements Supplements containing polyvalent cations like calcium, iron, magnesium, and zinc can interfere with the absorption of INSTIs by binding to them in the gut (a process called chelation) [1.5.4, 1.6.2]. To avoid this, these supplements should be taken several hours apart from INSTI medications, often with specific guidance on timing with or without food [1.2.5].
| Substance to Avoid/Use with Caution | Interacting Antiretroviral Class(es) | Potential Effect | Recommendation |
|---|---|---|---|
| St. John's Wort | PIs, NNRTIs, INSTIs (some) | Decreases ARV levels, risk of treatment failure [1.4.5] | Contraindicated/Do Not Use [1.6.1] |
| Acid Reducers (PPIs, Antacids) | Rilpivirine, Atazanavir, INSTIs | Decreases ARV absorption [1.5.2] | Avoid or separate doses by several hours [1.3.6] |
| Certain Statins (Simvastatin, Lovastatin) | PIs, Cobicistat-boosted regimens | Increases statin levels, risk of toxicity [1.3.3] | Contraindicated/Use alternative statin [1.3.3] |
| Grapefruit Juice | PIs, Maraviroc, some INSTIs | Increases ARV levels, risk of side effects [1.6.1] | Avoid or use with caution [1.2.2] |
| Garlic Supplements (High Dose) | PIs (e.g., Saquinavir) | Decreases ARV levels [1.6.7, 1.6.1] | Use with caution; consult provider [1.6.1] |
| Mineral Supplements (Calcium, Iron) | INSTIs | Decreases INSTI absorption via chelation [1.5.4] | Separate doses by 2-6 hours [1.2.5] |
Conclusion
Managing HIV with antiretroviral therapy is a lifelong commitment that requires careful attention to what else you put in your body. Drug and supplement interactions are common and can undermine the effectiveness of your treatment. The most crucial action is to maintain an open and honest dialogue with your healthcare provider and pharmacist. Always inform them of any new medication, supplement, or even significant dietary changes you plan to make. This partnership is your best defense against harmful interactions and is key to long-term health.
Disclaimer: This article is for informational purposes only and does not constitute medical advice. Always consult with a qualified healthcare professional before making any decisions about your treatment. Authoritative Link: HIV Drug Interactions - University of Liverpool
