HIV: Guide to Protease Inhibitors

HIV: Guide to Protease Inhibitors

Antiretrovirals for HIV

The outlook for HIV has improved dramatically over the years. This is in large part thanks to new drugs that block the virus from infecting cells and copying itself inside your body. These drugs are called antiretrovirals because they work against retroviruses like HIV. To copy itself, HIV uses RNA as its primary genetic material instead of DNA, which is the primary genetic material for animals, plants, and most other microorganisms.

Protease inhibitors are one type of antiretroviral drug. When you’re treated with antiretroviral medications, the goal is to reduce the amount of HIV virus in your body (called viral load) as much as possible. This effect slows the progression of HIV and also helps treat symptoms.

How protease inhibitors work


The main purpose of HIV is to copy itself as many times as it can. However, HIV lacks the machinery it needs to reproduce itself. Instead, it injects its genetic material into certain cells in your body. It then uses your body’s immune cells as a kind of HIV virus factory.

Protease is an enzyme in your body that’s important for HIV replication. Protease inhibitor drugs block the action of protease. That means they prevent the protease enzyme from doing its part in the steps that allow HIV to multiply. In this way, protease inhibitors can interrupt the HIV lifecycle. This can stop the virus from multiplying in your body.

Protease inhibitor drugs


Protease inhibitor drugs that are approved by the U.S. Food and Drug Administration (FDA) to treat HIV include:

Read more: What to know about complementary and alternative treatments to drugs for HIV »

Effectiveness of protease inhibitors


You need to take protease inhibitors with other medications to treat your HIV well. To be fully effective, almost all protease inhibitors need to be taken with either ritonavir or cobicistat. Your doctor will likely also prescribe two other HIV medications in addition to the protease inhibitor, ritonavir, and cobicistat. Your doctor may give you the protease inhibitor and other drugs as separate pills. Or, you may take them together in one combined pill.

Adherence and resistance
Take all of your HIV medications exactly as your doctor prescribes. Do not make any changes on your own. If you do not take all of your medications exactly as prescribed, your HIV could become resistant to your drugs. This means that the drugs would no longer work to treat your virus

Side effects from protease inhibitors


Like most medications, protease inhibitors can cause side effects. These can include:

  • changes in how foods taste
  • fat redistribution (storing body fat in different places on your body)
  • diarrheainsulin resistance (when your body can’t use the hormone insulin well)
  • high blood sugar levels
  • high cholesterol or triglyceride (blood fat) levels
  • increased risk of bleeding in people with hemophilia
  • liver problems
  • nausea
  • vomiting
  • rash
  • jaundice (yellowing of your skin and the whites of your eyes), most often associated with atazanavir use

Learn more: HIV drug side effects and consequences for adherence »

Interactions with other drugs

Complications Icon

Protease inhibitors also can interact with other drugs. These include statin medications, which are drugs used to lower your cholesterol. These include:

Taking protease inhibitors with any of these drugs can raise the amount of statin drug in your body. This can increase your risk for side effects from the statin. These effects can include muscle pain and kidney damage.

The protease inhibitor ritonavir (Norvir), in particular, interacts with a lot of other drugs. This interaction could cause a heart rhythm problem called long QT syndrome.

Protease inhibitor drugs can also interact with over-the-counter (OTC) drugs that decrease stomach acid. These can include omeprazole (Prilosec), ranitidine (Zantac), and Tums. Your doctor may tell you not to take these drugs together or to take them at different times of the day.

Fluticasone (Flonase) is an OTC allergy medication that can also interact with most HIV drugs.

Talk to your doctor about any of the drugs you’re taking. This includes any prescribed drugs, over-the-counter medications, herbs, and supplements. Your doctor can give you the most complete and current information about the known interactions with your HIV drugs.

Doctor discussion

Talk therapy

Talk to your doctor about whether protease inhibitors are a good drug choice for you. When used with other medications, these drugs can be very effective in easing your symptoms and slowing the progression of your HIV. Still, these medications have notable side effects and interactions. You and your doctor can review the benefits and drawbacks to decide if protease inhibitors are a good fit for you.