Guanfacine and Lopinavir and ritonavir interaction
Guanfacine and Lopinavir and ritonavir: 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 Lopinavir and ritonavir (Kaletra) label · effective 2026-07-23
…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: triazolam, orally administered midazolam KALETRA is contraindicated with drugs that are potent CYP3A inducers where significantly reduced lopinavir plasma concentrations…
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.
Sedative/Hypnotics: parenterally administered midazolam ↑ midazolam If KALETRA is co-administered with parenteral midazolam, close clinical monitoring for respiratory depression and/or prolonged sedation should be exercised and dosage adjustment should be considered.
From the Guanfacine (Intuniv) label · effective 2025-06-23
…Interactions: Effect of other Drugs on INTUNIV Concomitant Drug Name or Drug Class Clinical Rationale and Magnitude of Drug Interaction Clinical Recommendation Strong and moderate CYP3A4 inhibitors, e.g., ketoconazole, fluconazole Guanfacine is primarily metabolized by CYP3A4 and its plasma concentrations can be significantly affected resulting in an increase…
Decrease INTUNIV to 50% of target dosage when coadministered with strong and moderate CYP3A4 inhibitors ( 2.7 ).
Strong and moderate CYP3A4 inducers decrease guanfacine exposure.
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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.