If you're getting treated for an HIV infection, your doctor may suggest a type of drug called an NRTI. It's short for "nucleoside/nucleotide reverse transcriptase inhibitor." Some people just call them "nukes."
NRTIs are usually combined with a drug in another class (like integrase inhibitors) in a treatment plan called antiretroviral therapy (ART). Sometimes you take this combination as a single pill.
Tell your doctor if you can't stick to your HIV medication plan for any reason. They'll help you find a strategy that works for you.
How Do NRTIs Treat HIV?
NRTIs halt one of the early steps in the HIV life cycle, which keeps the virus from spreading. They do this by blocking an enzyme called reverse transcriptase that helps HIV make copies of itself.
There are several FDA-approved NRTIs. They include:
- Abacavir (Ziagen)
- Emtricitabine (Emtriva)
- Lamivudine (Epivir)
- Tenofovir alafenamide (Vemlidy)
- Tenofovir disoproxil fumarate (Viread)
- Zidovudine (Retrovir)
Most people with HIV take more than one NRTI at a time. Some common combos include:
Which NRTI Should You Take?
That's a decision you'll make with your doctor. They'll need to check your blood to see if certain NRTIs won't work for you. That's called drug-resistance testing. They'll also consider things like possible side effects or if you:
- Take other medicine
- Are pregnant
- Have infections or other health problems
How Do You Take Them?
In general, NRTIs come in pill form. Young children can use a liquid mix if they have a hard time swallowing pills.
If this is your first time on ART, your doctor will start you off with one or two NRTIs along with an antiretroviral from another class of medications. Many of your drugs are combined into one pill that you'll take every day. That's called a fixed-dose combination.
It may be OK to take your medicine with or without food. But always check with your doctor for exact instructions.
It's important to take your medicine every day. If you skip doses every now and then, HIV can spread and change in your body. Your medicine may stop working.
NRTIs and Side Effects
Like any drug, NRTIs can cause some unwanted side effects. Some mild symptoms may go away when your body gets used to the drug. Others might not. Tell your doctor if your medicine makes you feel bad. They can help manage your symptoms. Sometimes you can switch to a different NRTI.
In general, common side effects include:
All NRTIs raise your chances of certain serious side effects. But these are less likely to happen with newer NRTIs like tenofovir, emtricitabine, lamivudine, and abacavir.
Rarely, NRTIs may cause:
- Buildup of lactic acid in your blood (lactic acidosis)
- Liver problems (hepatotoxicity)
- Hypersensitivity reaction (skin rash, hepatotoxicity, fever)
You may not have any problems when you take NRTIs. But you should get medical help right away if you have certain symptoms, including:
Your doctor will run blood tests before and during treatment to keep tabs on your health. But there are some problems that may come up with certain NRTIs:
Lamivudine and emtricitabine have the highest chance of drug resistance. That's why they're added to other drugs.
Abacavir may cause a serious allergic reaction in some people. This is more likely to happen if you have a genetic variation called HLA-B*5701. Your doctor will run a blood test to check for it.
If you do start abacavir, tell your doctor right away if you get symptoms like:
- Nausea or throwing up
- Shortness of breath
If you have a reaction, you can’t take abacavir again since it could be life-threatening.
Tenofovir disoproxil fumarate may cause:
- Bone density loss
- Kidney problems
Your doctor can switch you to tenofovir alafenamide if you get these health issues.
Tenofovir alafenamide is safer for your bones and kidneys, but it may cause weight gain.
Zidovudine may cause: