What to Know About Biktarvy Side Effects

Every medication comes with potential side effects, and Biktarvy is no exception. The good news is that Biktarvy is generally well-tolerated — most people who take it experience mild side effects or none at all. But it's important to know what to watch for so you can tell the difference between something normal and something that needs medical attention.

This guide covers the common side effects, the serious ones, and when you should call your doctor.

What Is Biktarvy?

Biktarvy is a once-daily tablet that combines three antiretroviral medications — bictegravir, emtricitabine, and tenofovir alafenamide (BIC/FTC/TAF) — into a single pill. It's used to treat HIV-1 in adults and children weighing at least 14 kg (31 lbs). For a deeper look at what Biktarvy is and how it works, see our guides on Biktarvy uses and dosage and how Biktarvy works.

Common Side Effects

In clinical trials, the most frequently reported side effects of Biktarvy were mild and often improved within the first few weeks of treatment. These include:

• Diarrhea — reported in about 6% of patients
• Nausea — reported in about 6% of patients
• Headache — reported in about 5% of patients
• Fatigue — feeling more tired than usual
• Abnormal dreams — vivid or unusual dreams during sleep
• Dizziness
• Insomnia — difficulty falling or staying asleep

These side effects are generally mild and tend to get better as your body adjusts to the medication. Most people find them manageable and don't need to stop treatment because of them.

Serious Side Effects

While uncommon, Biktarvy can cause serious side effects that require immediate medical attention:

Hepatitis B Flare-Ups (Boxed Warning)

This is the most important warning on Biktarvy's label. If you have both HIV and hepatitis B and you stop taking Biktarvy, your hepatitis B can suddenly get much worse — sometimes severely. Your doctor should test you for hepatitis B before you start Biktarvy, and monitor your liver function closely if you stop the medication.

Do not stop taking Biktarvy without talking to your doctor first.

Lactic Acidosis

Rarely, Biktarvy's components can cause a buildup of lactic acid in the blood. Symptoms include unusual muscle pain, trouble breathing, stomach pain with nausea and vomiting, feeling cold (especially in arms and legs), and feeling dizzy or lightheaded. This is a medical emergency.

Severe Liver Problems

In rare cases, the medication can cause severe liver enlargement (hepatomegaly) with fat buildup (steatosis). Warning signs include yellowing of the skin or eyes, dark urine, light-colored stools, and pain in the upper right side of your abdomen.

Immune Reconstitution Inflammatory Syndrome (IRIS)

When your immune system starts recovering after starting HIV treatment, it may begin fighting infections that were previously hidden. This can cause symptoms of those infections to appear or get worse. IRIS is most common in the first few weeks to months of treatment and is more likely if your immune system was very weak before starting Biktarvy.

Kidney Problems

Biktarvy can cause new or worsening kidney problems, including kidney failure. Your doctor should check your kidney function before you start and periodically during treatment. Tell your doctor right away if you notice decreased urination, blood in your urine, or swelling in your legs or feet.

Bone Density Loss

Some patients experience decreases in bone mineral density while taking Biktarvy. This is generally mild, but your doctor may monitor this if you have other risk factors for bone loss.

Who May Be at Higher Risk

Certain groups should be especially aware of side effects:

• Patients with hepatitis B co-infection — higher risk of liver flare-ups if Biktarvy is stopped
• Patients with kidney problems — Biktarvy is not recommended if your creatinine clearance is below 30 mL/min
• Patients with severe liver disease — Biktarvy is not recommended in severe hepatic impairment
• Pregnant or breastfeeding patients — limited data on use during pregnancy; breastfeeding is not recommended due to risk of HIV transmission
• Patients taking certain other medications — some drug interactions can increase side effect risk

How to Manage Common Side Effects

If you're experiencing mild side effects, these tips may help:

• Nausea — try taking Biktarvy with food. Eat smaller, more frequent meals. Avoid spicy or greasy foods.
• Diarrhea — stay hydrated. Over-the-counter medications like loperamide (Imodium) can help, but check with your doctor first.
• Headache — over-the-counter pain relievers like acetaminophen (Tylenol) are generally safe. Avoid ibuprofen if you have kidney concerns.
• Insomnia or abnormal dreams — try taking Biktarvy in the morning rather than at bedtime. Practice good sleep hygiene.
• Fatigue — this often improves over the first few weeks. Stay active and maintain a regular sleep schedule.

If any side effect is persistent or bothersome, talk to your doctor. There may be ways to adjust your treatment. If Biktarvy isn't working well for you, your provider can discuss alternative HIV medications.

When to Call Your Doctor

Call your doctor right away if you experience:

• Unusual muscle pain or weakness
• Trouble breathing
• Stomach pain with nausea and vomiting
• Yellowing of skin or eyes
• Dark-colored urine
• Feeling cold, especially in your arms and legs
• Dizziness or lightheadedness that won't go away
• Decreased urination or swelling in your legs or feet
• Signs of a new or worsening infection after starting treatment

If you think you're having a medical emergency, call 911 or go to the nearest emergency room.

Final Thoughts

Biktarvy has a strong safety profile and is well-tolerated by most patients. The common side effects — diarrhea, nausea, and headache — are usually mild and temporary. Serious side effects are rare but important to know about. The key is to stay in regular contact with your doctor, get your scheduled lab work done, and never stop taking Biktarvy without medical guidance. With proper monitoring, most people do very well on this medication.