Generic name: Saquinavir.

Invirase is a protease inhibitor. It blocks the protease enzyme vital to the final stages of human immunodeficiency virus (HIV) replication, reducing the amount of virus available to infect new cells. 

Quick Facts About Invirase


Used in combination with other drugs called nucleoside analogues (such as Retrovir or Hivid) to treat advanced HIV infection in selected patients. HIV causes the immune system to break down so that it can no longer fight off infections. It can lead to the fatal disease known as acquired immune deficiency syndrome (AIDS). Does not cure HIV infection.

Invirase Dosage

Take within 2 hours after a full meal to allow medication to be absorbed properly by the body. Take exactly as prescribed, at even intervals around the clock. Do not discontinue use without consulting your doctor.

  • Usual adult dose: 600 milligrams (three 200-milligram capsules) taken 3 times per day (every 8 hours).
  • Usual child dose: not prescribed for children.
  • Missed dose: take as soon as possible, unless almost time for next dose. In that case, do not take missed dose; go back to regular schedule. Do not double doses.

Invirase Side Effects

Overdose symptoms:

none reported. However, if you suspect an overdose, immediately seek medical attention.

More common side effects: abdominal discomfort, diarrhea, sores on mouth.

Less common Invirase side effects: abdominal pain, headache, muscle or bone pain, nausea, numbness in the arms and legs, rash, vomiting, weakness. Rare side effects: appetite changes, confusion, dizziness, lack of coordination, “pins and needles” sensation, seizures, severe skin reaction.


Do not combine Invirase with astemizole (Hismanal) or terfenadine (Seldane).

Inform your doctor before combining Invirase with:

calcium channel blockers such as amlodipine (Norvasc), diltiazem (Cardizem, Dilacor XR), felodipine (Plendil), isradipine (Dyna-Circ), nicardipine (Cardene), nisoldipine (Sular), or verapamil (Calan, Isoptin, or Verelan); cisapride (Propulsid); clonidine (Catapres); enzyme inducers such as carbamazepine (Tegretol), phenobarbital (Donnatal), phenytoin (Dilantin), rifabutin (Mycobutin), or rifampin (Rifadin or Rimactane); quinidine (Quinaglute or Quinidex); or triazolam (Halcion).

Avoid grapefruit juice while taking Invirase; may reduce medication’s effectiveness.

Special Cautions

If pregnant or planning to become pregnant, inform f your doctor immediately. Do not breastfeed; HIV appears in breast milk and could affect a nursing infant

No special precautions apply to seniors.

Not generally prescribed for children under 16 years.

  • Long-term effects of medication still are not known. Since the HIV virus remains in the body, risk is still present for complications including opportunistic infections such as pneumonia, tuberculosis, and fungal infection. It is important to remain under the care of a doctor and go to follow-up appointments.
  • Inform your doctor before treatment if you have liver disease (especially cirrhosis) or kidney disease.
  • Invirase can be taken alone, but is most effective when combined with nucleoside analogues (such as Retrovir or Hivid).
  • Does not reduce risk of transmitting HIV to others through sexual contact or blood contamination. Always use condoms and never share needles or equipment for injections with other people.

Note: provides accurate and independent information prescription pills, over-the-counter medicines and natural products. This material is provided for educational purposes only and is not intended for medical advice, diagnosis or treatment. If you have questions about  dosage, or Invirase side effects, please contact your healthcare provider.