If you're taking Tenofovir Disoproxil for HIV treatment, PrEP, or hepatitis B, knowing which drugs interact with it is essential for your safety. Some interactions can increase your risk of side effects, while others can make your treatment less effective.

This guide covers the most important Tenofovir Disoproxil drug interactions, including prescription medications, over-the-counter drugs, and supplements.

How Drug Interactions Work with Tenofovir Disoproxil

Drug interactions can happen in several ways:

• Increased drug levels — Some medications increase the amount of Tenofovir Disoproxil in your blood, raising the risk of side effects like kidney damage.
• Decreased drug levels — Other drugs can lower the levels of medications you take alongside Tenofovir Disoproxil, making them less effective.
• Additive toxicity — When two drugs that affect the same organ (like the kidneys) are taken together, the combined effect can be harmful.
• Competition for elimination — Tenofovir Disoproxil is eliminated through the kidneys, and drugs that compete for the same elimination pathways can cause problems.

Prescription Medications That Interact with Tenofovir Disoproxil

Major Interactions — Avoid or Use with Extreme Caution

• Didanosine (Videx) — Taking Tenofovir Disoproxil with didanosine significantly increases didanosine concentrations, raising the risk of serious toxicity including pancreatitis, neuropathy, and lactic acidosis. Co-administration should generally be avoided. If it must be used, didanosine doses must be reduced.
• Adefovir Dipivoxil (Hepsera) — Do not take Tenofovir Disoproxil with adefovir. Both drugs work through the same mechanism and taking them together provides no additional benefit while increasing the risk of kidney toxicity.
• Nephrotoxic agents — Medications that can harm the kidneys should be used cautiously with Tenofovir Disoproxil. These include:
  • Aminoglycoside antibiotics (gentamicin, tobramycin)
  • Cidofovir
  • Foscarnet
  • IV pentamidine
  • High-dose or IV vancomycin
  • Amphotericin B
  If these are necessary, your doctor should monitor kidney function more frequently.

Moderate Interactions — Monitor Closely

• Atazanavir (Reyataz) — Tenofovir Disoproxil decreases atazanavir blood levels, which can make the HIV protease inhibitor less effective. When used together, atazanavir should be boosted with ritonavir (atazanavir/ritonavir 300/100 mg).
• Lopinavir/ritonavir (Kaletra) — This combination increases Tenofovir Disoproxil levels in the blood, which may raise the risk of kidney side effects. Monitor kidney function closely.
• Ledipasvir/sofosbuvir (Harvoni) — Used for hepatitis C treatment, this combination may increase tenofovir levels, particularly when taken with a boosted protease inhibitor. Renal monitoring is recommended.

Over-the-Counter Medications and Supplements

NSAIDs (Anti-Inflammatory Pain Relievers)

Non-steroidal anti-inflammatory drugs like ibuprofen (Advil, Motrin), naproxen (Aleve), and aspirin (at high doses) can increase the risk of kidney problems when taken regularly with Tenofovir Disoproxil. Occasional use is generally fine, but regular daily use should be discussed with your doctor.

Safer alternative: Acetaminophen (Tylenol) is generally safer for pain relief while on Tenofovir Disoproxil, as it doesn't affect the kidneys in the same way. Use it at recommended doses.

Herbal Supplements

While there are no well-documented major interactions between Tenofovir Disoproxil and common herbal supplements, some supplements can affect kidney function or liver enzymes. Be cautious with:

• St. John's Wort — Can reduce the effectiveness of many HIV medications. While its direct interaction with Tenofovir Disoproxil is minimal, if you're on a multi-drug HIV regimen, St. John's Wort could reduce the effectiveness of your other medications.
• High-dose creatine supplements — May affect kidney function tests, making it harder for your doctor to monitor Tenofovir Disoproxil's impact on your kidneys.

Antacids and Buffered Medications

Tenofovir Disoproxil can generally be taken with antacids without significant interactions. However, if you're taking it as part of a combination regimen, check whether your other HIV or HBV medications have antacid restrictions.

Food and Drink Interactions

Tenofovir Disoproxil has minimal food interactions:

• Food — Can be taken with or without food. High-fat meals may slightly increase absorption, but this is not clinically significant. Taking it with food may help reduce nausea.
• Alcohol — There is no direct interaction between Tenofovir Disoproxil and alcohol. However, heavy alcohol use can damage the liver and kidneys, potentially worsening the side effects of Tenofovir Disoproxil. Moderate alcohol consumption is generally considered acceptable, but discuss your habits with your doctor.
• Grapefruit — Unlike many medications, Tenofovir Disoproxil is not significantly affected by grapefruit juice.

What to Tell Your Doctor

Before starting Tenofovir Disoproxil, make sure your doctor knows about:

• All prescription medications — including other HIV drugs, hepatitis treatments, antibiotics, and antifungals
• Over-the-counter medications — especially NSAIDs, antacids, and any regular pain medications
• Supplements and herbs — including vitamins, minerals, protein powders, and herbal remedies
• Kidney or liver problems — past or present, as these affect how Tenofovir Disoproxil is processed
• Pregnancy or plans to become pregnant — Tenofovir Disoproxil is generally considered safe in pregnancy, but your full medication list needs review

Keep an updated medication list and bring it to every appointment. This is especially important if you see multiple providers, as different doctors may prescribe medications that interact.

Final Thoughts

Tenofovir Disoproxil has a manageable interaction profile, but the interactions that do exist — particularly with nephrotoxic drugs, didanosine, and regular NSAID use — are important. The biggest theme is kidney protection: anything that adds stress to your kidneys deserves extra attention while you're on this medication.

Always keep your healthcare team informed about everything you take, and don't start or stop any medication without checking first. For more on Tenofovir Disoproxil, see our guides on side effects, uses and dosage, and how to save money.

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