Ritomune Ritonavir 100 Mg Tablet

Q1: What is Ritomune (Ritonavir 100mg) used for?

Ritomune is used almost exclusively as a pharmacokinetic booster (not as a primary antiviral) to enhance the blood levels of other protease inhibitors including Lopinavir, Atazanavir, and Darunavir. At 100mg, it acts as a CYP3A4 inhibitor to prevent rapid metabolism of companion PIs.

Q2: How does Ritonavir boosting work?

Ritonavir at 100mg potently inhibits CYP3A4 liver enzymes that would otherwise rapidly metabolise co-administered PIs. This inhibition increases PI plasma concentrations 10–20 fold, maintaining therapeutic drug levels throughout the day with once-daily dosing of the companion PI.

Q3: Why is Ritonavir used at 100mg rather than the original 600mg?

At 600mg twice daily, Ritonavir had excellent antiviral activity but unacceptable GI side effects (severe diarrhea, nausea). At the low 100mg boosting dose, Ritonavir has minimal antiviral activity itself but effectively boosts companion PIs with much better tolerability.

Q4: How is Ritomune 100mg taken?

Take 100mg with food at the prescribed time, always together with the companion PI (Lopinavir, Atazanavir, or Darunavir). The companion PI and Ritonavir must be taken together and WITH FOOD — food significantly enhances absorption. Do not take on an empty stomach.

Q5: What are the most common side effects at 100mg?

At the low 100mg boosting dose, side effects are much milder than at higher doses. Common effects include mild GI disturbances (nausea, diarrhea), elevated cholesterol and triglycerides, and elevated liver enzymes. Perioral (around the mouth) and peripheral (hands, feet) tingling can occur.

Q6: What is the drug interaction burden of Ritonavir?

Ritonavir has one of the most extensive drug interaction profiles of any medication. It inhibits and induces multiple CYP enzymes, affecting dozens of drug classes including statins (lovastatin/simvastatin contraindicated), certain antifungals, immunosuppressants, anticoagulants, and antiarrhythmics. A comprehensive interaction check with a pharmacist is essential before starting any new medication.

Q7: Can Cobicistat replace Ritonavir for boosting?

Yes. Cobicistat (COBI) is an alternative pharmacokinetic booster with similar CYP3A4 inhibition and no antiviral activity. It has slightly fewer drug interactions than Ritonavir and better tolerability in some patients. Your HIV specialist will determine the appropriate booster.

Q8: What monitoring is required during Ritonavir therapy?

Fasting lipid panel (cholesterol, triglycerides) every 6–12 months — boosted PI regimens can significantly elevate lipids. Liver function tests at baseline and periodically. Blood glucose monitoring. CD4 and viral load every 3–6 months.

Q9: Is Ritonavir 100mg safe during pregnancy?

Ritonavir 100mg as a booster can be used in pregnancy. Pharmacokinetics may change in pregnancy, potentially requiring dose adjustments. Always managed by an HIV/OB specialist team.

Q10: What happens if Ritonavir is missed with a companion PI?

Missing Ritonavir doses causes the companion PI levels to fall, potentially dropping below therapeutic concentrations and increasing resistance risk. Ritonavir must be taken consistently at the prescribed time with its companion PI.

Q11: How should Ritomune 100mg be stored?

Store at room temperature away from light and moisture. Tablets (unlike older capsules) do not require refrigeration. Keep in original packaging out of reach of children.

Q12: Do I need a prescription for Ritomune?

Yes. Ritonavir requires specialist HIV prescribing as part of a boosted PI regimen. Its extensive drug interactions make it particularly important to coordinate all medications through a specialist pharmacist.