Why Drug Interactions Matter With Tivicay

Tivicay (Dolutegravir) is one of the most effective HIV medications available, but it can interact with other drugs, supplements, and even antacids in ways that could make it less effective or cause harmful side effects. Knowing these interactions could literally save your life.

This guide covers every major Tivicay drug interaction you need to know about — from medications that are completely off-limits to supplements that just need to be timed carefully.

The One Medication You Absolutely Cannot Take With Tivicay

Dofetilide (Tikosyn) — CONTRAINDICATED

Dofetilide is a heart medication used to treat atrial fibrillation and atrial flutter. Tivicay cannot be taken with Dofetilide under any circumstances.

Here's why: Dolutegravir inhibits a transporter called OCT2 (organic cation transporter 2) in the kidneys. This transporter is responsible for clearing Dofetilide from your body. When Tivicay blocks OCT2, Dofetilide levels build up in your blood, which can cause dangerous heart rhythm problems (QT prolongation) that could be life-threatening.

If you take Dofetilide and need HIV treatment, your doctor must choose a different antiretroviral. Tell any new prescriber about your Dofetilide use before starting any HIV medication.

Medications That Require a Tivicay Dose Increase

Several medications speed up how your body metabolizes Dolutegravir, reducing the amount of drug in your blood. If the level drops too low, the virus won't be fully suppressed. For these medications, your doctor will increase Tivicay from 50 mg once daily to 50 mg twice daily:

Rifampin

Rifampin is used to treat tuberculosis (TB) and some other infections. It's a potent enzyme inducer that significantly reduces Dolutegravir levels. If you need both Tivicay and Rifampin, the Tivicay dose must be doubled to 50 mg twice daily. TB and HIV co-infection is common, so this interaction comes up frequently in clinical practice.

Certain Anti-Seizure Medications

The following seizure medications are strong enzyme inducers that lower Dolutegravir levels:

• Carbamazepine (Tegretol)
• Oxcarbazepine (Trileptal)
• Phenytoin (Dilantin)
• Phenobarbital

If you take any of these, your Tivicay dose needs to increase to 50 mg twice daily. Never adjust your dose on your own — always work with your doctor.

Certain Other HIV Medications

Some antiretroviral medications also reduce Dolutegravir levels when taken together:

• Efavirenz (Sustiva)
• Fosamprenavir/ritonavir (Lexiva/Norvir)
• Tipranavir/ritonavir (Aptivus/Norvir)

These combinations require Tivicay 50 mg twice daily. Your HIV care provider will know about these interactions and adjust your regimen accordingly.

Medications That Tivicay Affects

Tivicay doesn't just get affected by other drugs — it also changes how some medications work in your body.

Metformin

Metformin is one of the most commonly prescribed diabetes medications. Dolutegravir increases Metformin levels in your blood by inhibiting OCT2 and MATE1 transporters in the kidneys. Higher Metformin levels can increase the risk of side effects like lactic acidosis.

If you take both Tivicay and Metformin, your doctor may need to:

• Reduce your Metformin dose when starting Tivicay
• Monitor blood sugar more closely during the adjustment
• Watch for Metformin side effects (nausea, diarrhea, muscle pain)

This interaction is especially important because diabetes is common among people living with HIV.

Supplements and Antacids: Timing Is Everything

Several common supplements and over-the-counter products contain minerals that can bind to Dolutegravir in your digestive tract, reducing how much of the drug gets absorbed into your blood.

Calcium Supplements

Calcium can reduce Dolutegravir absorption. Follow these rules:

• Without food: Take Tivicay 2 hours before or 6 hours after calcium supplements
• With food: You can take them at the same time

Iron Supplements

Iron binds strongly to Dolutegravir. Same timing rules as calcium:

• Without food: Take Tivicay 2 hours before or 6 hours after iron
• With food: You can take them together

Magnesium Supplements and Antacids

Many antacids (like Maalox, Mylanta, and Tums) contain magnesium, aluminum, or calcium. These can all reduce Dolutegravir absorption.

• Without food: Take Tivicay 2 hours before or 6 hours after antacids
• With food: You can take them at the same time

Multivitamins

Many multivitamins contain iron, calcium, and magnesium. The same timing rules apply. Check your multivitamin label — if it contains any of these minerals, plan your dosing schedule accordingly.

Herbal Products to Avoid

St. John's Wort

Do not take St. John's wort with Tivicay. This popular herbal supplement is a potent enzyme inducer that can significantly decrease Dolutegravir levels in your blood. Even at the increased dose of 50 mg twice daily, the interaction may not be fully overcome. Your doctor will advise you to avoid St. John's wort entirely.

How to Tell Your Doctor About All Your Medications

Drug interactions with Tivicay are manageable — but only if your doctor knows about everything you're taking. Here's a checklist:

• Prescription medications — All of them, from every doctor you see
• Over-the-counter medications — Including antacids, pain relievers, allergy medications, and sleep aids
• Supplements — Vitamins, minerals, fish oil, probiotics, protein powders
• Herbal products — St. John's wort, echinacea, garlic supplements, turmeric, and any others
• Recreational substances — Some can interact with HIV medications

Keep an updated medication list on your phone or in your wallet. Show it to every healthcare provider you see, including dentists and urgent care doctors.

What Happens If You Take an Interacting Medication?

The consequences depend on the interaction:

• Reduced Dolutegravir levels — The virus may not be fully suppressed, leading to viral rebound and potentially drug resistance. This is why dose adjustments matter.
• Increased Dofetilide levels — Potentially life-threatening heart rhythm problems.
• Increased Metformin levels — Higher risk of lactic acidosis and other Metformin side effects.
• Reduced absorption from minerals — Lower Dolutegravir levels, similar to enzyme inducers but correctable with proper timing.

If you accidentally took an interacting medication, don't panic — but do call your doctor or pharmacist right away for guidance.

Interactions With Tivicay Combination Products

If you take a combination product that contains Dolutegravir — such as Triumeq, Dovato, or Juluca — the same Dolutegravir interactions apply. Additionally, the other components in those pills have their own interactions. Always check with your pharmacist or doctor before adding any new medication.

Tips for Managing Drug Interactions

1. Use one pharmacy — Your pharmacist's computer can flag interactions across all your prescriptions.
2. Set reminders — If you need to time Tivicay around supplements, use phone alarms to stay on schedule.
3. Don't stop Tivicay on your own — Even if you're worried about an interaction, stopping HIV treatment is almost always more dangerous. Call your doctor first.
4. Ask your pharmacist — They're drug interaction experts and can answer quick questions without an appointment.
5. Check before starting anything new — Even something as simple as an antacid can affect Tivicay absorption.

When to Call Your Doctor About a Drug Interaction

Contact your prescriber if:

• Another doctor prescribes you a new medication
• You start a new supplement or herbal product
• You experience new side effects after changing medications
• Your viral load increases after previously being undetectable
• You're unsure whether something interacts with Tivicay

The Bottom Line

Tivicay is a highly effective medication, but it does interact with several common drugs and supplements. The most important things to remember: never take Dofetilide with Tivicay, time your mineral supplements carefully, avoid St. John's wort, and always tell your doctor about everything you take.

For more about Tivicay, read our guides on what Tivicay is, how it works, and how to save money. Need to find Tivicay in stock? Search on MedFinder.