Does Fasting Fog Your Brain or Sharpen It? The Data Might Surprise You
November 5, 2025
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Brand Name :
Invirase
Synonyms :
saquinavir
Class :
Protease Inhibitors, HIV
Brand Name :
Invirase
Synonyms :
saquinavir
Class :
Protease Inhibitors, HIV
Dosage Forms & StrengthsÂ
Tablet Â
500mgÂ
<16 years: Safety and efficacy are not established
>16 years: Administer 1000mg along with 100mg of ritonavir twice a day
There is no need for extra ritonavir in individuals receiving 100 mg twice daily of ritonavir as a component of their ART treatment.
Patients with no prior treatment
Initial dose-Administer 500mg orally twice a day along with 100mg of ritonavir twice a day for 7 days, then can increase the dose to 1000mg/100mg orally twice a day.
Investigation involving kids who have received therapy
≥2 years, ≥40 kg: Administer 50 mg/kg and 100mg of ritonavir orally twice daily.
≥2 years, 5 to <15 kg: Administer 50 mg/kg and 3mg of ritonavir orally twice daily.
≥2 years, 15 to 40 kg: Administer 50 mg/kg and 2.5mg of ritonavir orally twice daily.
<2 years: Safety and efficacy not established
Dosage Forms & StrengthsÂ
Tablet Â
500mgÂ
Refer adult dosingÂ
saquinavir: they may enhance serum concentrations of rifabutin
may enhance the serum concentration of CYP3A4 Inhibitors
may increase the QTc-prolonging effect of QT-prolonging CYP3A4 Inhibitors
may enhance serum concentrations of the CYP3A4 Inhibitors
may enhance the serum concentration of CYP3A4 Inhibitors
may enhance the serum concentration of CYP3A4 Inhibitors
may enhance the serum concentration of CYP3A4 Inhibitors
may enhance the serum concentration of CYP3A4 Inhibitors
may enhance the serum concentration of CYP3A4 Inhibitors
may enhance the serum concentration of CYP3A4 Inhibitors
may enhance the serum concentration of CYP3A4 Inhibitors
may increase the QTc-prolonging effect of each other when combined
may increase the QTc-prolonging effect of each other when combined
may increase the QTc-prolonging effect of each other when combined
may increase the QTc-prolonging effect of each other when combined
may increase the QTc-prolonging effect of each other when combined
saquinavir and gilteritinib, when used in combination, increase the QTc interval
when both drugs are combined, there may be an increase in the QTC interval
when both drugs are combined, there may be an increased risk of adverse effects 
antipsychotic agents increase the effect of arrhythmia of saquinavir
antipsychotic agents increase the effect of arrhythmia of saquinavir
antipsychotic agents increase the effect of arrhythmia of saquinavir
antipsychotic agents increase the effect of arrhythmia of saquinavir
antipsychotic agents increase the effect of arrhythmia of saquinavir
saquinavir: they may increase the QTc-prolonging effect of clozapine
when both drugs are combined, the metabolism of paclitaxel decreases when compared with saquinavir  
when both drugs are combined, there may be an increased risk or severity of QTC prolongation  
QTc interval is increased both by lenvatinib and saquinavir
when both drugs are combined, there may be an increased effect of ivosidenib by affecting hepatic or intestinal enzyme cyp3a4 metabolism  
saquinavir increases the effect of lapatinib by altering the intestinal or hepatic CYP3A4 enzyme metabolism
CYP3A strong enhancers of the small intestine may reduce the bioavailability of saquinavir management: consider alternatives to strong CYP3A enhancers in patients treated with saquinavir if combined, monitor closely for signs of decreased saquinavir concentrations and effects 
saquinavir increases the effect of fedratinib by altering the intestinal/hepatic CYP3A4 enzyme metabolism
it increases the effect or level of ruxolitinib by altering the intestinal or hepatic CYP3A4 enzyme metabolism
it increases the concentration of sunitinib in serum
may enhance the serum concentration of elbasvir/grazoprevir
may increase the serum concentration of lidocaine when combined
It may enhance serum concentration when combined with CYP3A4 Inhibitors (Moderate)
It may enhance serum concentration when combined with CYP3A4 Inhibitors (Moderate)
It may enhance serum concentration when combined with CYP3A4 Inhibitors (Moderate)
It may enhance serum concentration when combined with CYP3A4 Inhibitors (Moderate)
It may enhance serum concentration when combined with CYP3A4 Inhibitors (Moderate)
may enhance the serum concentration of CYP3A4 Inhibitors
may enhance the serum concentration of CYP3A4 Inhibitors
when both drugs are combined, there may be an increased effect of cabozantinib  
has a synergistic effect over brentuximab vedotin by showing altered intestinal/hepatic CYP3A4 enzyme metabolism.
increases serum levels by affecting hepatic metabolism of docetaxel
saquinavir increases the effect of gefitinib by altering the intestinal/ hepatic CYP3A4 enzyme metabolism
osimertinib and saquinavir, when used simultaneously, increase the QTc interval
May enhances the effects of the other by pharmacodynamic synergism
May enhances the effects of the other by pharmacodynamic synergism
may increase the level by affecting the hepatic enzyme CYP3A4 metabolism
may increase the level by affecting the hepatic enzyme CYP3A4 metabolism
may increase the level by affecting the hepatic enzyme CYP3A4 metabolism
it increases by affecting the hepatic enzyme CYP3A4 metabolism
may enhance the serum concentration of P-glycoprotein inhibitors
It may enhance toxicity when combined with cholic acid by diminishing the elimination
saquinavir, when taken with ixazomib, alters the intestinal/hepatic CYP3A4 enzyme metabolism
Actions and Spectrum:Â
HIV replication involves several steps, one of which is the maturation of viral particles. The virus produces a protein called protease, which plays a crucial role in cutting large viral polyproteins into smaller functional proteins. This proteolytic cleavage is essential for forming mature and infectious viral particles.Â
saquinavir works by inhibiting the activity of the HIV protease enzyme. It binds to the active site of the protease enzyme, preventing it from cleaving viral polyproteins accurately. This inhibition disrupts the maturation process of the newly produced viral particles, rendering them non-infectious and unable to cause further infection. Essentially, saquinavir interferes with the final step of HIV replication, reducing the production of new infectious virions.Â
saquinavir primarily targets HIV-1, the most common and virulent strain of the virus responsible for causing acquired immunodeficiency syndrome (AIDS). It is ineffective against HIV-2, another strain of the less prevalent virus, primarily found in some areas of West Africa.Â
Frequency definedÂ
1-10%Â
HyperglycemiaÂ
Abdominal discomfortÂ
Abdominal painÂ
ParesthesiaÂ
RashÂ
DiarrheaÂ
NauseaÂ
Buccal mucosa ulcerationÂ
<1%Â
ConfusionÂ
AtaxiaÂ
Stevens-Johnson syndromeÂ
Hyper- & hypokalemiaÂ
Low serum amylaseÂ
HeadacheÂ
SeizuresÂ
PainÂ
HypoglycemiaÂ
Black box warning:Â
Contraindications/caution:Â
Contraindications:Â
Caution:Â
Pregnancy consideration: Insufficient data availableÂ
Lactation: Excretion of the drug in human breast milk is unknownÂ
Pregnancy category:Â
Category A: well-controlled and Satisfactory studies show no risk to the fetus in the first or later trimester.Â
Category B: there was no evidence of risk to the fetus in animal studies, and there were not enough studies on pregnant women.Â
Category C: there was evidence of risk of adverse effects in animal reproduction studies, and no adequate evidence in human studies must take care of potential risks in pregnant women.   Â
Category D: adequate data with sufficient evidence of human fetal risk from various platforms, but despite the potential risk, and used only in emergency cases for potential benefits.   Â
Category X: Drugs listed in this category outweigh the risks over benefits. Hence these categories of drugs need to be avoided by pregnant women.   Â
Category N: There is no data available for the drug under this categoryÂ
Pharmacology:Â
saquinavir is an antiretroviral medication belonging to the class of protease inhibitors. Its pharmacology involves inhibiting the protease enzyme of the human immunodeficiency virus (HIV), thereby interfering with the virus’s ability to replicate and mature.Â
Pharmacodynamics:Â Â
saquinavir reduces viral replication and helps control the spread of HIV in the body.Â
Pharmacokinetics:Â
AbsorptionÂ
saquinavir has poor absorption from the gastrointestinal tract. Its absorption is improved when taken with a high-fat meal.Â
Approximately 98% of saquinavir is bound to plasma proteins.Â
Distribution:Â
saquinavir does not effectively cross the blood-brain barrier, meaning it does not distribute into the central nervous system (CSF). The apparent volume of distribution of saquinavir is 700 liters. Â
MetabolismÂ
saquinavir is extensively metabolized in the liver primarily by the cytochrome P450 enzyme CYP3A4. It undergoes significant first-pass metabolism, which means a large portion of the drug is metabolized before it reaches systemic circulation.Â
Elimination and ExcretionÂ
saquinavir is mainly eliminated through feces (81-88%). A small portion of the drug is excreted in the urine (1-3%)Â
Administration:Â
Oral administrationÂ
saquinavir along with ritonavir should be administered 2 hours after eating.Â
Patient information leafletÂ
Generic Name: saquinavirÂ
Why do we use saquinavir?Â
saquinavir is a medication primarily used to treat HIV (human immunodeficiency virus) infection. It belongs to the class of antiretroviral drugs known as protease inhibitors. Here are the main uses of saquinavir:Â
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