Living With HIV and Other Conditions: How to Prevent Medication Interactions

What Is a Medication Interaction?

• Absorption interference: A change in how much of either drug makes it into the bloodstream, increasing or decreasing the amount that’s available for the body to use.
• Metabolism shifts: A change in how the body breaks down or processes medications, typically occurring because liver enzymes of the cytochrome P450 (CYP) family, especially CYP3A, play a significant role in metabolizing both ART medications and many other common drugs.

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• Excretion alterations: A change in how quickly the kidneys clear the drug from the body.

Everyday Pills That Can Interact With HIV Meds

HIV medications have dramatically improved over time, and the “number of drug interactions [with newer medications] has really declined through the decades,” says Dominic Chow, MD, PhD, MPH, a professor with the Hawai'i Center for AIDS and the University of Hawai'i Department of Medicine. “Pharmaceutical companies have done a splendid job of really creating [HIV] medications that have very little side effects and little interactions.”

Some everyday drugs that can interact with HIV medications include:

• Antacids, H2 Blockers, and Proton Pump Inhibitors Medications used to treat issues like indigestion, heartburn, and gastrointestinal reflux disease (GERD) can alter the acidity of the stomach, reducing how much older HIV medications like atazanavir and rilpivirine get absorbed into the body.

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  The way these medications work may also lower the level of medication absorbed by your body.
• Multivitamins and Mineral Supplements Multivitamins and supplements containing calcium, magnesium, or iron can bind to and block the absorption of certain HIV medications, especially older integrase strand transfer inhibitors (INSTIs).

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• Cholesterol-Lowering Statins Some statins are metabolized by CYP3A enzymes, and combining them with certain HIV medications can spike statin concentrations, potentially causing serious muscle damage.

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• Corticosteroids, Including Inhalers and Nasal Sprays Certain HIV medications can cause CYP3A-metabolized steroids to build up in the body, leading to life-threatening adrenal insufficiency (low hormone levels) or Cushing's syndrome (excessively high cortisol).

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• Phosphodiesterase Type 5 (PDE5) Inhibitors Sildenafil, tadalafil, and other PDE5 inhibitors are commonly used to treat erectile dysfunction and high blood pressure, but the drugs’ concentrations can spike to dangerous levels when used alongside HIV medications like protease inhibitors and cobicistat-boosted elvitegravir.

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• Blood Thinners Certain HIV medications can raise or lower the concentrations of warfarin, so providers closely monitor patients who use both types of medications and adjust dosages accordingly. Other blood thinners, including apixaban, dabigatran, and rivaroxaban, can reach unsafe levels when combined with some HIV drugs.

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• Hormonal Birth Control Some HIV medications can lower the effectiveness of hormonal contraceptives, leading to unintended pregnancies. This is more likely to occur with oral and transdermal contraceptives than with intrauterine devices (IUDs) and injectable depot-medroxyprogesterone acetate (DMPA).

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• Herbal Supplements St. John's wort, garlic supplements, ginkgo biloba, and grapefruit can all interact with HIV medications and affect how well they work.

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• Mental Health Medications Certain HIV medications can reduce or increase the levels of certain drugs used to treat mental health conditions, including various antipsychotics, selective serotonin reuptake inhibitors (SSRIs), tricyclic antidepressants, and benzodiazepines.

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How to Prevent Drug Interactions

Pharmacists can also be great sources of information about interactions with both prescription and over-the-counter (OTC) medications, says Raymond Alejo, RN, a community health nurse with the Hawai'i Health and Harm Reduction Center in Honolulu. “Pharmacists are playing a much bigger role in patient teaching than they did when I first started,” says Alejo, who’s provided HIV services in Hawai'i for more than 25 years. “I really like that, because what happens is that they’ll tell the patient, then they’ll also tell the healthcare provider about it.”

But Blumenthal notes that this communication may not always occur or your pharmacist may flag an interaction that your provider has already deemed acceptable. “If you do start an over-the-counter medication,” she says, “it’s probably best practice to message your provider and ask, ‘Is it okay? Is there any reason I can’t take this medication?’”

Here are some other simple steps you can take to prevent drug interactions.

• Read drug labels and package inserts thoroughly (these will list known interactions).

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• Keep a complete, updated medication list, including your prescriptions, OTC drugs, recreational drugs, and supplements.

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• Loop in every prescriber and provider, who may not know about your full medication regimen.

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• Use a trusted interaction tracker, such as the University of Liverpool’s HIV drug interaction checker.