Saquinavir

INVIRASE

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Pronunciation: sa-KWIN-a-veer

Saquinavir ballicule: receptor binding, kinetics and half-life diagram — Mechanism of action: Saquinavir ballicule

What it isThe first HIV protease inhibitor; HIV.

Why this oneIt proved that protease inhibition worked, which made combination antiretroviral therapy possible.

What limits itPoor bioavailability required boosting, and QT and PR prolongation limit it. Effectively obsolete.

Saquinavir molecular structure (skeletal formula) — Molecular structure: Saquinavir

Saquinavir prescription history

Animated chart of estimated U.S. prescriptions per year, HIV antiretrovirals (1987–2026). Saquinavir enters in 1995 (estimated).

FDA-approved for

HIV infection (1995)

Principal riskPoor bioavailability required boosting, and QT and PR prolongation limit it

Classes and tags

Clinical profile

Therapeutic safety burden3 / 4

Overdose danger2 / 4

Weight-gain liability1 / 4

Sedation liability1 / 4

QT / Torsades4 / 4

Direct muscarinic antagonism0 / 4

Legacy pregnancy categoryB

Defining liabilityQT/PR prolongation and extensive boosted-regimen interactions

FDA label

Read the full label on DailyMed ↗

NO BOXED WARNINGS

FDA dosing	Population	Start	Target	Max
HIV-1 infection (with ritonavir + other antiretrovirals)	Adult >16y	1000 mg BID	1000 mg BID	1000 mg BID

Renal Undefined

Hepatic Contraindicated (with ritonavir) in severe hepatic impairment

Doses <1000 mg with ritonavir not recommended (no antiviral activity)

Instructions

Must be used in combination with ritonavir 100 mg BID
Take within 2 hours after a meal
Take ritonavir at the same time as Invirase

Available strengths

cap 200 mg
tab 500 mg

Contraindications

Severe hepatic impairment (when given with ritonavir)
Concurrent rifampin (risk of severe hepatocellular toxicity)
Concurrent CYP3A4-dependent drugs causing serious/life-threatening reactions (ergot derivatives, midazolam, triazolam, pimozide, cisapride, astemizole, terfenadine)

Cautions

Must be used in combination with ritonavir
Interrupt for serious/severe toxicity until etiology identified or toxicity resolves
Do not use with lovastatin/simvastatin; caution with other CYP3A4-metabolized statins (myopathy incl. rhabdomyolysis)
St. John's wort not recommended (loss of virologic response, resistance)
Fluticasone with INVIRASE/ritonavir not recommended (Cushing's syndrome, adrenal suppression)
Monitor digoxin levels; digoxin dose reduction may be needed
New-onset/exacerbated diabetes mellitus and hyperglycemia (protease-inhibitor class)
Worsening liver disease reported in hepatitis B/C, cirrhosis, chronic alcoholism; caution in hepatic impairment
Hyperlipidemia — monitor cholesterol/triglycerides before and during therapy (marked triglycerides risk pancreatitis)
Spontaneous bleeding in hemophilia A/B (protease-inhibitor class)
Fat redistribution/accumulation; immune reconstitution syndrome
Caution in severe renal impairment (not studied)

Adverse reactions

Nausea
Vomiting
Diarrhea
Diabetes mellitus/hyperglycemia
Lipodystrophy

Pregnancy Undefined

Lactation Undefined

Cost

Saquinavir (INVIRASE)

Strength		#/mo	generic $/mo	CostPlus
500 mg	tab	60 BID		not offered
200 mg	cap	60 BID		not offered

NADAC is a voluntary CMS survey of what retail community pharmacies pay for the drugs they stock. Saquinavir is dispensed outside retail pharmacies, so it rarely appears on surveyed invoices.

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Self-check

Saquinavir: Why did it require boosting?
Poor bioavailability.
Saquinavir: Which ECG intervals can prolong?
QT and PR.