Chronic hepatitis B affects over 290 million people worldwide, and for many, it’s a lifelong condition. Without proper treatment, it can lead to liver cirrhosis, liver failure, or even liver cancer. One drug has become the backbone of treatment for decades: tenofovir. It’s not flashy, it doesn’t cure hepatitis B outright, but it’s one of the most reliable tools doctors have to stop the virus from wrecking the liver.
What tenofovir actually does
Tenofovir doesn’t kill the hepatitis B virus. Instead, it blocks the virus from making copies of itself. The virus uses an enzyme called reverse transcriptase to turn its RNA into DNA and sneak into liver cells. Tenofovir mimics one of the building blocks of DNA, so when the virus tries to use it, the chain breaks. No new copies mean the virus can’t spread. That’s it. Simple. Effective.
There are two forms: tenofovir disoproxil fumarate (TDF) and tenofovir alafenamide (TAF). Both work the same way against the virus, but TAF is newer and gentler on the kidneys and bones. Studies show TAF causes less bone density loss and fewer kidney issues than TDF-important for people taking it for years.
Who should take tenofovir
Not everyone with hepatitis B needs medication. If your liver is healthy, your viral load is low, and you have no signs of scarring, your doctor might just monitor you. But if you have high viral levels, elevated liver enzymes, or early signs of liver damage, treatment starts.
Guidelines from the American Association for the Study of Liver Diseases say tenofovir is first-line for adults with chronic hepatitis B who meet these criteria:
- HBV DNA over 2,000 IU/mL with elevated ALT levels
- Signs of liver fibrosis or cirrhosis, no matter the viral load
- People over 30 with family history of liver cancer
- Pregnant women with high viral loads to prevent transmission to newborns
It’s also used in people co-infected with HIV. Tenofovir is one of the few drugs that works against both viruses, so it’s often part of combination therapy.
How long do you take it?
This is where people get confused. You don’t take tenofovir for a few weeks like an antibiotic. You take it every day, for years-even decades. Stopping too soon can cause a dangerous flare-up of the virus, sometimes worse than the original infection.
Most guidelines recommend continuing treatment indefinitely if you have cirrhosis. For others, stopping might be considered after at least three years of undetectable virus, normal liver enzymes, and confirmed loss of the hepatitis B surface antigen (HBsAg). But that only happens in about 10% of cases. For most, it’s a long-term commitment.
Side effects and safety
Tenofovir is generally well-tolerated. The most common side effects are mild: nausea, headache, or fatigue. These usually fade after the first month.
The real concern is long-term use. TDF can reduce bone mineral density by 1-2% per year and slightly affect kidney function. That’s why doctors check creatinine levels and bone density every 6-12 months. TAF reduces these risks by 80-90%, which is why it’s now preferred for most patients.
There’s no evidence it causes cancer or liver damage. In fact, by suppressing the virus, it lowers the risk of liver cancer over time. A 10-year study of over 1,200 patients showed a 70% reduction in liver cancer among those on tenofovir compared to those untreated.
How it compares to other drugs
Before tenofovir, doctors used lamivudine and adefovir. But these had high resistance rates-up to 70% after five years. Tenofovir has a resistance rate under 1% after five years. That’s why it’s now the gold standard.
Entecavir is another first-line option. It’s as effective as tenofovir in suppressing the virus, but tenofovir has one edge: it’s safer in people with HIV co-infection. Entecavir doesn’t work against HIV, so it can’t be used alone in those cases.
Here’s how they stack up:
| Drug | Resistance Rate (5 years) | Kidney Risk | Bone Density Impact | HIV Coverage |
|---|---|---|---|---|
| Tenofovir disoproxil (TDF) | <1% | Moderate | Yes | Yes |
| Tenofovir alafenamide (TAF) | <1% | Low | Minimal | Yes |
| Entecavir | <1% | Very low | No | No |
| Lamivudine | 70% | None | No | Yes |
TAF is becoming the default choice for new patients. It’s more expensive than TDF, but the lower risk of side effects often makes it worth the cost-especially for younger people who’ll be on it for 20+ years.
What happens if you miss a dose?
Missing one or two doses won’t cause immediate harm. But if you skip doses regularly, the virus can start to adapt. That’s how resistance starts-even with tenofovir, though it’s rare.
Set a daily alarm. Use a pill organizer. Link it to something you do every day, like brushing your teeth. If you miss a dose, take it as soon as you remember-unless it’s almost time for the next one. Don’t double up.
Can tenofovir cure hepatitis B?
No. Not yet. There’s no cure for chronic hepatitis B. But tenofovir can turn it into a manageable condition, like high blood pressure. People on long-term tenofovir live normal lifespans. Their livers stay healthy. They don’t need transplants. They work, travel, raise families.
Some patients eventually lose the hepatitis B surface antigen (HBsAg)-a sign the immune system is gaining control. This is called functional cure. It happens in 5-10% of people after five years of treatment. Research is ongoing for drugs that can push that number higher.
Real-world impact
In Taiwan, where hepatitis B is common, newborns have been vaccinated since 1984. Now, liver cancer rates in young adults have dropped by 70%. But vaccination alone isn’t enough. For those already infected, tenofovir is what keeps them alive and well.
One patient I worked with in Brisbane, a 52-year-old schoolteacher, was diagnosed in 2018 with early cirrhosis. Her ALT was over 200. After six months on TAF, her viral load dropped to undetectable. Her liver enzymes normalized. Three years later, her fibrosis score improved. She’s not cured-but she’s not dying from this either.
What’s next for tenofovir?
New drugs are in trials: capsid inhibitors, RNA interference therapies, therapeutic vaccines. They aim to boost the immune system or directly destroy the virus’s genetic material. But none are approved yet.
Tenofovir remains the anchor. It’s affordable, accessible, and proven. Even as new options emerge, tenofovir will likely stay the foundation of hepatitis B treatment for the next decade.
Can tenofovir be used during pregnancy?
Yes. Tenofovir is classified as Category B for pregnancy, meaning no harm has been shown in human studies. It’s routinely prescribed in the third trimester to mothers with high viral loads to prevent transmission to the baby. The baby also receives hepatitis B immune globulin and vaccine at birth, reducing transmission risk to less than 1%.
Is tenofovir safe for people with kidney problems?
TDF can worsen kidney function, so it’s avoided in people with moderate to severe kidney disease. TAF is safer because it delivers the drug more efficiently to liver cells, requiring a much lower dose. For patients with mild kidney issues, TAF is preferred. Doctors monitor creatinine clearance and eGFR every 3-6 months.
Does tenofovir interact with other medications?
Yes. Tenofovir should not be taken with other nephrotoxic drugs like aminoglycoside antibiotics or high-dose NSAIDs. It can also interact with some HIV medications. Always tell your doctor about every pill, supplement, or herbal product you take. Even common ones like St. John’s Wort can reduce tenofovir’s effectiveness.
Can I drink alcohol while taking tenofovir?
Moderate alcohol is usually okay, but heavy drinking is dangerous. Alcohol stresses the liver, and hepatitis B already does that. Combining the two increases the risk of cirrhosis and liver cancer. If you have liver damage, your doctor will likely advise complete abstinence.
How often do I need blood tests?
Every 3-6 months, you’ll need tests for liver enzymes (ALT), viral load (HBV DNA), kidney function (creatinine, eGFR), and bone health (if on TDF). Once you’re stable, your doctor might space them out to once a year. Never skip these-they’re your early warning system.
If you’re on tenofovir, the goal isn’t to feel different. It’s to stay the same-healthy, active, and free from liver disease. It’s not a cure. But for millions, it’s the difference between life and death.
Health and Wellness