Lopinavir and ritonavir and Meperidine interaction
Lopinavir and ritonavir and Meperidine: both prescribing labels flag this combination with the strongest language, such as a contraindication, a boxed warning, or an instruction to avoid it.
Do not combine without a prescriber's guidance. The label language below is the strongest FDA uses.
What the FDA labels say
From the Meperidine (DEMEROL) label · effective 2026-07-20
Cytochrome P450 3A4 Interaction The concomitant use of DEMEROL Injection with all cytochrome P450 3A4 inhibitors may result in an increase in meperidine plasma concentrations, which could increase or prolong adverse reactions and may cause potentially fatal respiratory depression.
In addition, discontinuation of a concomitantly used cytochrome P450 3A4 inducer may result in an increase in meperidine plasma concentration.
Monitor patients receiving DEMEROL Injection and any CYP3A4 inhibitor or inducer [see Warnings and Precautions (5.5) , Drug Interactions (7) ] .
• Concomitant use with CYP3A4 inhibitors (or discontinuation of CYP3A4 inducers) can result in a fatal overdose of meperidine.
Risks of Concomitant Use or Discontinuation of Cytochrome P450 3A4 Inhibitors and Inducers Concomitant use of DEMEROL Injection with a CYP3A4 inhibitor, such as macrolide antibiotics (e.g., erythromycin), azole-antifungal agents (e.g., ketoconazole), and protease inhibitors (e.g., ritonavir), may increase plasma concentrations of meperidine and prolong opioid…
From the Lopinavir and ritonavir (Kaletra) label · effective 2026-07-23
…Hepatitis C direct acting antiviral: elbasvir/grazoprevir HMG-CoA Reductase Inhibitors: lovastatin, simvastatin Microsomal triglyceride transfer protein (MTTP) Inhibitor: lomitapide Non-opioid Analgesic (selective blocker of Nav1.8 sodium channels): suzetrigine PDE5 Inhibitor: sildenafil (Revatio ® ) when used for the treatment of pulmonary arterial hypertension Sedative/Hypnotics:…
Postmarketing life-threatening cases of cardiac toxicity (including complete AV block, bradycardia, and cardiomyopathy), lactic acidosis, acute renal failure, CNS depression and respiratory complications leading to death have been reported, predominantly in preterm neonates receiving KALETRA oral solution.
Sedative/Hypnotics: triazolam, orally administered midazolam ↑ triazolam ↑ midazolam Contraindicated due to potential for prolonged or increased sedation or respiratory depression [see Contraindications ( 4 )] .
…potential risks, infants should be monitored closely for increases in serum osmolality and serum creatinine, and for toxicity related to KALETRA oral solution including: hyperosmolality, with or without lactic acidosis, renal toxicity, CNS depression (including stupor, coma, and apnea), seizures, hypotonia, cardiac arrhythmias and ECG changes, and hemolysis.
Analgesics Opioid: methadone* fentanyl Non-opioid analgesic (selective blocker of Na v 1.8 sodium channels): suzetrigine ↓ methadone ↑ fentanyl ↑ suzetrigine and active metabolite M6-SUZ Dosage of methadone may need to be increased when co-administered with KALETRA.
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Open in the checkerNot medical advice. Interaction Checker quotes FDA label text and NIH fact sheets. Whether an interaction matters for you depends on doses, timing, kidney and liver function, and other conditions. Confirm with a pharmacist or prescriber.