- What are protease inhibitors (PIs), and how do they work?
- List of 16 examples of brand and generic names available for protease inhibitors (PIs) in the US
- What are the uses for protease inhibitors (PIs)?
- What are the side effects of HIV protease inhibitors (PIs)?
- What are the side effects of hepatitis C virus (HCV) protease inhibitors?
- What drug interactions occur with protease inhibitors (PIs)?
- Are protease inhibitors (PIs) safe to use during pregnancy or while breastfeeding?
- What forms and preparations of protease inhibitors (PIs) are available?
What are protease inhibitors (PIs), and how do they work?
Protease inhibitors (PIs) are antiviral drugs used for treating human immunodeficiency virus (HIV) infections and hepatitis C virus (HCV) infections.
During infection with HIV or hepatitis C, the HIV or HCV multiply within the body's cells. Viruses are released from the cells and spread throughout the body where they infect other cells. In this manner, HIV and hepatitis C infection is perpetuated among new cells that the body produces continually. During the production of the viruses, new proteins are made. Some of the proteins are structural proteins that form the body of the virus. Other proteins are enzymes that manufacture DNA and other components for the new viruses. Protease is an enzyme that is used in the formation of new structural proteins and enzymes. Protease inhibitors block the activity of protease (cleavage of protein precursors needed for viral structure synthesis) and this results in the formation of defective viruses that are unable to infect the body's cells. As a result, the number of HIV or hepatitis C viruses in the body (the viral load) decreases.
List of 16 examples of brand and generic names available for protease inhibitors (PIs) in the US
HIV protease inhibitors
- Aptivus (tipranavir)
- Reyataz (atazanavir)
- Crixivan, IDV (indinavir)
- Prezista (darunavir)
- Lexiva (fosamprenavir)
- Invirase (saquinavir)
- Kaletra (lopinavir/ritonavir)
- Viracept (nelfinavir)
- Norvir (ritonavir)
Hepatitis C virus (HCV) protease inhibitors
- Victrelis (boceprevir - discontinued)
- Incivek (telaprevir - discontinued)
- Olysio (simeprevir)
- Technivie (ombitasvir/paritaprevir and ritonavir, a combination of these three drugs)
- Viekira Pak (ombitasvir/paritaprevir/ritonavir and dasabuvir, a combination of these four drugs)

QUESTION
Hepatitis C virus causes an infection of the ______________. See AnswerWhat are the uses for protease inhibitors (PIs)?
- Protease inhibitors are used to treat HIV or hepatitis C virus infections. HIV protease inhibitors do not prevent the transmission of HIV among individuals, and they do not cure HIV infection or AIDS. However, HIV protease inhibitors can reduce the viral load to very low levels and reduce the risk of opportunistic infections. The discovery of HIV protease inhibitors revolutionized the management of HIV infection and the course of the disease.
- Hepatitis C virus protease inhibitors can cure hepatitis C infection, and are more effective than other hepatitis C treatments.
- The FDA approved the first hepatitis C virus protease inhibitor in 2011.
What are the side effects of HIV protease inhibitors (PIs)?
Common side effects of HIV protease inhibitors:
Serious side effects of HIV protease inhibitors include:
- Skin reactions
- Liver failure
- Seizures
- Failure of the pancreas (pancreatitis)
- Redistribution or accumulation of body fat
- Increased cholesterol
- Worsening of diabetes
- Heart block
- Immune reconstitution syndrome
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What are the side effects of hepatitis C virus (HCV) protease inhibitors?
Common side effects of hepatitis C virus protease inhibitors:
- Rash
- Itching
- Muscle pain
- Headache
- Shortness of breath (dyspnea)
- Nausea
- Fatigue
- Diarrhea
- Dizziness
- Hyperbilirubinemia
- Elevated alkaline phosphatase
- Elevated amylase
- Elevated lipase
Serious side effects of hepatitis C virus protease inhibitors include:
- Liver failure
- Sun sensitivity
- Severe skin reactions
- Reactivation of HBV infection (hepatitis B virus)

SLIDESHOW
Hepatitis: How Do You Get Hepatitis A, B, and C? See SlideshowWhat drug interactions occur with protease inhibitors (PIs)?
Protease inhibitors have many drug interactions because they affect the action of liver enzymes that alter many drugs and because several other drugs affect the breakdown of protease inhibitors in the liver. Here are some examples of protease inhibitor drug interactions.
Protease inhibitor drugs may increase blood levels of the following drugs:
- alfuzosin (Uroxatral)
- doxazosin (Cardura)
- silodosin (Rapaflo)
- tamsulosin (Flomax)
- sildenafil (Viagra, Revatio)
- tadalafil (Cialis)
- warfarin (Coumadin, Jantoven)
- simvastatin (Zocor)
- lovastatin (Mevacor)
- amiodarone (Cordarone)
These drugs may increase blood levels of protease inhibitors:
- ketoconazole (Nizoral)
- itraconazole (Sporanox)
- fluconazole (Diflucan)
- voriconazole (Vfend)
- clarithromycin (Biaxin)
- erythromycin (Erythrocin)
- fluoxetine (Prozac)
The following drugs reduce blood levels of protease inhibitors:
- carbamazepine (Tegretol)
- phenobarbital
- phenytoin (Dilantin)
- rifampin
- St. John's Wort
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Are protease inhibitors (PIs) safe to use during pregnancy or while breastfeeding?
- Lopinavir/ritonavir and indinavir/ritonavir combinations are used for the treatment of HIV-infected pregnant women. Other HIV protease inhibitor regimens have not been adequately studied in pregnant women, may not be effective, or may have unacceptable toxicity.
- Hepatitis C virus protease inhibitors have not been adequately evaluated in pregnant women or nursing mothers.
- The patient's OB/GYN doctor should be consulted before protease inhibitors are used in a pregnant or nursing woman. Guidelines are available for the use of protease inhibitors in pregnant women, neonates, and children (see references).
What forms and preparations of protease inhibitors (PIs) are available?
- Protease inhibitors are supplied as capsules, tablets, oral suspension or solution, and powder for suspension.
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Summary
Protease Inhibitors (PIs) are a class of antiviral drugs prescribed to treat HIV and hepatitis (HCV) viral infections. There are several protease inhibitors that treat HIV infection, for example: Lexiva (fosamprenavir), Invirase (saquinavir), Kaletra (lopinavir/ritonavir), Viracept (nelfinavir), Norvir (ritonavir). Examples of hepatitis C virus protease inhibitors include, Olysio (simeprevir), Technivie (ombitasvir/paritaprevir and ritonavir, a combination of these three drugs), Viekira Pak (ombitasvir/paritaprevir/ritonavir and dasabuvir, a combination of these four drugs).
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Related Disease Conditions
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Hepatitis (Viral Hepatitis A, B, C, D, E, G)
Hepatitis is most often viral, due to infection with one of the hepatitis viruses (A, B, C, D, E, F (not confirmed), and G) or another virus (such as those that cause infectious mononucleosis, cytomegalovirus disease). The main nonviral causes of hepatitis are alcohol and drugs. Many patients infected with hepatitis A, B, and C have few or no symptoms of illness. For those who do develop symptoms of viral hepatitis, the most common are flu-like symptoms including: loss of appetite, nausea, vomiting, fever, weakness, tiredness, and aching in the abdomen. Treatment of viral hepatitis is dependent on the type of hepatitis.
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Hepatitis C (HCV, Hep C)
Hepatitis C is an inflammation of the liver due to the hepatitis C virus (HCV), which is usually spread by blood transfusion, hemodialysis, and needle sticks, especially with intravenous drug abuse. Symptoms of chronic hepatitis include fatigue, fever, muscle aches, loss of appetite, and fever. Chronic hepatitis C may be cured in most individuals with drugs that target specific genomes of hepatitis C.
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HIV and AIDS
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Is Hepatitis C Contagious?
Hepatitis C or hep C causes acute and chronic liver disease. Hep C is a form of liver disease with symptoms like fatigue, jaundice, nausea and vomiting, anorexia, and abdominal discomfort. Hepatitis C is a contagious viral infection caused by persons sharing drug needles, surgical instruments that have not been properly sanitized, and organ transplantation.
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AIDS (Acquired Immunodeficiency Syndrome)
AIDS is the advanced stage of HIV infection. Symptoms and signs of AIDS include pneumonia due to Pneumocystis jiroveci, tuberculosis, toxoplasmosis, seizures, weakness, meningitis, yeast infection of the esophagus, and Kaposi's sarcoma. Anti-retroviral therapy (HAART) is used in the treatment of AIDS.
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Human Immunodeficiency Virus (HIV)
HIV (human immunodeficiency virus) infection left untreated causes AIDS (acquired immunodeficiency syndrome). Still incurable, AIDS describes immune system collapse that opens the way for opportunistic infections and cancers to kill the patient. Early symptoms and signs of HIV infection include flu-like symptoms and fungal infections, but some people may not show any symptoms for years. Highly active antiretroviral therapy (ART) is the standard treatment for HIV infection. These combination drug regimens have made HIV much less deadly, but a cure or vaccine for the pandemic remains out of reach. HIV is usually transmitted through sexual contact or sharing IV drug needles, but can also infect someone through contact with infected blood. Sexual abstinence, safe sex practices, quitting IV drugs (or at least using clean needles), and proper safety equipment by clinicians and first responders can drastically reduce transmission rates for HIV/AIDS.
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Is Hepatitis Contagious?
Hepatitis means "inflammation of the liver," and there are several different types of such as A, B, C, D, and E. Some types of hepatitis are contagious and some types are not. Hepatitis symptoms vary upon the type of disease; however, the following symptoms may develop in someone with hepatitis: fatigue, nausea and vomiting, abdominal pain and discomfort, jaundice (yellowing of the skin and whites of the eyes), and loss of appetite. Treatment for hepatitis depends upon the cause. Some types of hepatitis have a vaccine to prevent spread of disease such as hepatitis A and B.
Treatment & Diagnosis
Medications & Supplements
- lopinavir and ritonavir (Kaletra): Potential COVID-19 Drug
- atazanavir (Reyataz)
- ritonavir (Norvir)
- indinavir, Crixivan
- saquinavir (Invirase, Fortovase - discontinued)
- simeprevir, Olysio
- nelfinavir, Viracept
- boceprevir (Victrelis)
- telaprevir (Incivek)
- Viekira Pak (ombitasvir, paritaprevir, ritonavir, and dasabuvir)
- fosamprenavir - oral, Lexiva
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Report Problems to the Food and Drug Administration
You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.
AIDSinfo.gov. "Recommendations for Use of Antiretroviral Drugs in Pregnant HIV-1-Infected Women for Maternal Health and Interventions to Reduce Perinatal HIV Transmission in the United States." Updated: Oct 26, 2016.
<https://aidsinfo.nih.gov/guidelines/html/3/perinatal-guidelines/0gt;
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