Molnupiravir

Generic name:

Molnupiravir

Drug class:

Oral antiviral; nucleoside analog; RNA polymerase inhibitor

Dosage form:

Capsules 200 mg

Root of administration:

Oral

Dose:

800 mg (four 200 mg capsules) every 12 hours for 5 days; adjustments: Varies by indication; consult label.

Mechanism of action:

Prodrug of N-hydroxycytidine which is incorporated by viral RNA-dependent RNA polymerase, inducing viral RNA mutagenesis and inhibiting replication.

Drug usage cases:

• Treatment of mild to moderate COVID-19 in adults at high risk of progression to severe disease
• Post-exposure prophylaxis of SARS-CoV-2 infection (off-label in some regions)
• Use in immunocompromised patients to reduce viral load (off-label)

Drug contra indications:

• Hypersensitivity to molnupiravir or any component of the formulation
• Pregnancy (unless benefits outweigh risks and no alternatives) – due to potential embryo-fetal toxicity
• Breastfeeding (avoid; potential for serious adverse reactions in breastfed child)
• Severe hepatic impairment (no clinical data; use with caution)
• Severe renal impairment (eGFR < 30 mL/min; use with caution)

Side effects:

• Diarrhea
• Nausea
• Dizziness
• Headache
• Muscle pain
• Fatigue
• Abdominal pain
• Anemia
• Elevated liver enzymes
• Thrombocytopenia
• Hypersensitivity reactions (rash, pruritus)

Warnings:

• Not a substitute for COVID-19 vaccination
• Potential for viral mutagenesis; avoid in pregnancy and breastfeeding
• May cause bone marrow toxicity; monitor blood counts in prolonged use
• Use caution in patients with renal or hepatic impairment
• Concomitant use with other mutagenic or teratogenic drugs may increase risk
• Benefit-risk should be assessed in pediatrics; safety not established
• May reduce efficacy of hormonal contraceptives; recommend additional contraceptive measures

Use during pregnancy or breastfeeding:

Animal studies have shown embryo-fetal toxicity. Molnupiravir may impair fetal development and is not recommended for use in pregnant individuals unless no alternatives exist and the potential benefit outweighs the risk. Women of childbearing potential should use effective contraception during treatment and for at least four days after the last dose. Breastfeeding should be discontinued during treatment and for at least four days after the last dose due to potential for serious adverse reactions in the breastfed infant.