Norvir (Ritonavir)

Norvir is a protease inhibitor used in the management of HIV‑1 infection and to enhance other antiretroviral agents.

• HIV‑1 infection: reduces viral load and improves immune function when used as part of combination therapy.
• Pharmacokinetic boosting of other protease inhibitors: increases plasma concentrations of co‑administered protease inhibitors, allowing lower dosing.
• Treatment‑experienced HIV‑1 patients: used in combination regimens to maintain viral suppression after prior therapy.

• Ritonavir inhibits the HIV‑1 protease enzyme, preventing cleavage of the gag‑pol polyprotein. This blockade results in the production of immature, non‑infectious viral particles, thereby reducing viral replication and spread within the host.

Ritonavir may cause a range of adverse reactions, from mild to severe.

Common Side Effects

• Nausea: occasional upset stomach.
• Diarrhea: loose stools, often transient.
• Abdominal pain: mild discomfort in the stomach area.
• Headache: mild to moderate tension.
• Fatigue: feeling unusually tired.
• Dyslipidemia: elevated cholesterol or triglycerides.

Serious or Rare Side Effects

• Hepatotoxicity: liver enzyme elevations or hepatitis.
• Severe allergic reactions: rash, angioedema, or anaphylaxis.
• QT prolongation: cardiac rhythm disturbances.
• Pancreatitis: inflammation of the pancreas.
• Severe hyperglycemia: marked increase in blood glucose.
• Stevens‑Johnson syndrome: severe skin and mucous membrane reaction.

Before prescribing Ritonavir, clinicians should assess patient-specific risk factors and monitor relevant parameters.

• Liver function monitoring: check hepatic enzymes regularly.
• Lipid profile assessment: evaluate cholesterol and triglycerides during therapy.
• Cardiac evaluation: caution in patients with known QT‑prolonging conditions.
• Drug interaction review: verify concomitant medications for CYP3A4 interactions.
• Use in hepatic impairment: avoid or adjust dose in severe liver disease.
• Store at room temperature: keep in the original container, protect from moisture and direct sunlight.

Ritonavir interacts with many medicines due to potent CYP3A4 inhibition.

Major Interactions (Avoid)

• Simvastatin or lovastatin: risk of severe myopathy.
• Certain anti‑arrhythmics (e.g., amiodarone): may cause cardiac toxicity.
• Pimozide: can lead to serious QT prolongation.

Moderate Interactions (Monitor Closely)

• Other protease inhibitors: dose adjustments may be required.
• Warfarin: monitor INR for altered anticoagulation.
• Oral contraceptives: efficacy may be reduced, consider alternative contraception.