Every medication comes with potential side effects, and Tenofovir Disoproxil is no exception. Whether you're taking it for HIV treatment, PrEP, or chronic hepatitis B, understanding what to expect — and knowing when something needs medical attention — can help you stay on track with your treatment.

This guide covers the most common side effects, the serious ones to watch for, and practical tips for managing them.

What Is Tenofovir Disoproxil?

Tenofovir Disoproxil Fumarate (brand name Viread) is a nucleotide reverse transcriptase inhibitor (NtRTI) used to treat HIV-1, prevent HIV infection (PrEP), and manage chronic hepatitis B. It's taken as a 300 mg tablet once daily. For a deeper overview, see our guide on what Tenofovir Disoproxil is and how it's used.

Common Side Effects

Most people tolerate Tenofovir Disoproxil well, but some experience mild side effects — especially in the first few weeks of treatment. These typically improve as your body adjusts:

• Nausea — One of the most commonly reported side effects. Taking the medication with food can help reduce stomach upset.
• Diarrhea — Usually mild and temporary. Staying hydrated and eating bland foods can help.
• Headache — Tends to be mild and often resolves within the first few weeks.
• Fatigue — Some people feel more tired than usual when starting treatment. This generally improves over time.
• Dizziness — Occasional lightheadedness may occur, particularly when standing up quickly.
• Flatulence and abdominal pain — GI symptoms are among the most common complaints but are usually manageable.
• Rash — A mild skin rash can occur. If it's severe or accompanied by other symptoms, contact your doctor.
• Depression — Mood changes have been reported. If you notice significant changes in mood or mental health, talk to your provider.

Important: most of these side effects are mild and go away on their own. Don't stop taking Tenofovir Disoproxil without talking to your doctor first — especially if you have hepatitis B, as stopping abruptly can cause a dangerous flare.

Serious Side Effects

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

Kidney Problems

Tenofovir Disoproxil is processed through the kidneys, and it can cause new or worsening kidney damage. This includes a rare but serious condition called Fanconi syndrome, where the kidneys fail to properly reabsorb essential nutrients. Symptoms to watch for:

• Decreased urine output
• Swelling in legs, ankles, or feet
• Unusual fatigue or weakness
• Muscle pain or bone pain

Your doctor should monitor your kidney function (creatinine and eGFR) regularly while you're on this medication. If you have pre-existing kidney issues, your doctor may need to adjust your dose or consider alternative medications like Tenofovir Alafenamide (TAF).

Lactic Acidosis

This is a rare but potentially fatal buildup of lactic acid in the blood. It's associated with nucleoside/nucleotide analogs as a class. Seek emergency medical care if you experience:

• Unusual muscle pain
• Trouble breathing
• Stomach pain with nausea and vomiting
• Feeling cold, especially in arms and legs
• Feeling very weak or tired
• Fast or irregular heartbeat

Severe Liver Problems

Severe hepatomegaly (enlarged liver) with steatosis (fatty liver) has been reported, including fatal cases. This risk is part of the FDA's boxed warning for Tenofovir Disoproxil. Signs include:

• Yellowing of skin or eyes (jaundice)
• Dark urine
• Light-colored stools
• Loss of appetite for several days
• Nausea and abdominal pain

Hepatitis B Flare

If you have hepatitis B and stop taking Tenofovir Disoproxil, you may experience a severe flare of your hepatitis. This is also a boxed warning. Your doctor should monitor your liver function closely for several months after discontinuation. Read more about this in our shortage update article, which discusses what to do if your supply is interrupted.

Decreased Bone Mineral Density

Long-term use of Tenofovir Disoproxil has been associated with decreases in bone mineral density. This is particularly important for:

• Adolescents and children (whose bones are still developing)
• Postmenopausal women
• Anyone with existing osteoporosis risk factors

Immune Reconstitution Syndrome

In patients starting HIV treatment, the recovering immune system may react to previously hidden infections, causing new symptoms. This usually happens in the first few weeks to months of treatment.

Special Populations

Certain groups should be especially mindful of side effects:

• Patients with kidney disease — Dose adjustments are needed for creatinine clearance below 50 mL/min. Tenofovir Disoproxil is not recommended for severe renal impairment without dose interval modification.
• Pregnant individuals — Tenofovir Disoproxil is classified as Pregnancy Category B and is generally considered safe for HIV treatment and prevention during pregnancy. Discuss risks and benefits with your provider.
• Pediatric patients — Bone density should be monitored in children and adolescents taking Tenofovir Disoproxil.
• Older adults — May be more susceptible to kidney and bone side effects due to age-related decline in organ function.

How to Manage Side Effects

Here are practical tips for dealing with common side effects:

• Take it with food — This can significantly reduce nausea and GI discomfort.
• Stay hydrated — Drinking plenty of water supports kidney function and can help with headaches and fatigue.
• Keep your follow-up appointments — Regular lab monitoring catches kidney and liver issues early, before they become serious.
• Don't take NSAIDs regularly — Over-the-counter pain relievers like ibuprofen and naproxen can increase kidney stress when combined with Tenofovir Disoproxil. Use acetaminophen instead when possible. Learn more about drug interactions with Tenofovir Disoproxil.
• Report new symptoms promptly — If something feels off, tell your doctor. Early detection of side effects leads to better outcomes.
• Consider supplements carefully — Calcium and vitamin D may help support bone health, but always check with your provider first.

Final Thoughts

Tenofovir Disoproxil is a well-established and effective medication that most people tolerate without major issues. The common side effects — nausea, headache, fatigue — are usually mild and temporary. The serious side effects — kidney damage, lactic acidosis, liver problems — are rare but important to know about.

The key is regular monitoring. As long as you keep up with your follow-up visits and lab work, your healthcare team can catch any issues early and adjust your treatment as needed.

If cost or availability is a concern, check out our guide on saving money on Tenofovir Disoproxil, or use Medfinder to find a pharmacy with it in stock near you.