Protease inhibitors are one type of antiretroviral drug used to treat HIV. Their goal is to reduce the amount of HIV virus in the body to levels that are undetectable. That said, protease inhibitors may have negative side effects.

The outlook for HIV has improved dramatically over the years.

This is in large part thanks to drugs called antiretrovirals. These drugs work in a person with HIV by blocking the virus from entering certain cells in their body and making copies of itself. These drugs are called antiretrovirals because they work against retroviruses such as HIV.

Protease inhibitors work to reduce the amount of HIV virus in the blood, also known as viral load. This slows the progression of HIV and helps treat symptoms.

Read on to learn more about protease inhibitors, such as how they work and what their potential side effects and interactions are.

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 immune cells in the body called CD4 cells. It then uses these cells as a kind of HIV virus factory.

Protease is an enzyme in the body that’s important for HIV replication. Protease inhibitor drugs block the action of protease enzymes. This prevents protease enzymes from doing their part in allowing HIV to multiply, interrupting the HIV life cycle as a result. This can stop the virus from multiplying. viral load

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

  • atazanavir (Reyataz)
  • darunavir (Prezista)
  • fosamprenavir (Lexiva)
  • indinavir (Crixivan)
  • lopinavir/ritonavir (Kaletra)
  • nelfinavir (Viracept)
  • ritonavir (Norvir)
  • saquinavir (Invirase)
  • tipranavir (Aptivus)
  • atazanavir/cobicistat (Evotaz)
  • darunavir/cobicistat (Prezcobix)

Protease inhibitors need to be taken along with other medications to treat HIV effectively. To be fully effective, almost all protease inhibitors need to be taken with either ritonavir or cobicistat.

In addition, two other HIV medications are typically prescribed along with the protease inhibitor and ritonavir or cobicistat. These medications may be given individually as separate pills or together in combination pills that contain multiple drugs.

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)
  • diarrhea
  • insulin resistance (when the body can’t use the hormone insulin well)
  • high blood sugar levels
  • high cholesterol or triglyceride levels
  • liver problems
  • nausea
  • vomiting
  • rash
  • jaundice (yellowing of the skin or the whites of the eyes), which is most often associated with the use of atazanavir

Protease inhibitors can interact with other drugs. People living with HIV should talk to their healthcare provider about all of the drugs they’re taking. This includes any prescription drugs, over-the-counter (OTC) medications, herbs, and supplements.

Healthcare providers can offer the most complete and current information about any known interactions with HIV drugs in a person’s treatment plan.

Interactions with prescription drugs

Prescription drugs that can interact with protease inhibitors include statin medications, which are drugs used to lower cholesterol. Examples of these drugs include:

Taking protease inhibitors with simvastatin or lovastatin can increase the amount of statin drug in the body. This can raise the risk of side effects from the statin. These side effects can include muscle pain and kidney damage.

Simvastatin and lovastatin are contraindicated with all protease inhibitors. This means these drugs should never be used with protease inhibitors because they could cause life-threatening side effects.

Protease inhibitors can also be involved in many other drug interactions. Types of drugs that can interact with protease inhibitors include:

Your healthcare provider or pharmacist can tell you more about these possible interactions.

Interactions with over-the-counter drugs

Protease inhibitors such as atazanavir can also interact with OTC drugs that decrease stomach acid.

These drugs include omeprazole (Prilosec), lansoprazole (Prevacid), cimetidine (Tagamet), famotidine (Pepcid), nizatidine (Axid), and antacids such as Tums.

Healthcare providers may tell people with HIV 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 protease inhibitors. In addition, St. John’s wort, the herbal supplement typically used for depression, can also interact with protease inhibitors and shouldn’t be used with these drugs.

People living with HIV should talk to their healthcare provider about whether protease inhibitors are a good choice for them. When used with other medications, these drugs can be very effective in easing symptoms and slowing the progression of HIV.

Still, these medications have notable side effects and interactions. Healthcare providers can review the benefits and drawbacks to decide if protease inhibitors are a good fit.