Lopinavir and ritonavir and Sildenafil interaction
Lopinavir and ritonavir and Sildenafil: 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
…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: triazolam, orally administered midazolam KALETRA is contraindicated…
Use of PDE5 inhibitors for pulmonary arterial hypertension (PAH): Sildenafil (Revatio ® ) is contraindicated [see Contraindications ( 4 )] .
Particular caution should be used when prescribing sildenafil, tadalafil, or vardenafil in patients receiving KALETRA.
PDE5 inhibitors: avanafil, sildenafil, tadalafil, vardenafil ↑ avanafil ↑ sildenafil ↑ tadalafil ↑ vardenafil Sildenafil when used for the treatment of pulmonary arterial hypertension (Revatio ® ) is contraindicated due to the potential for sildenafil-associated adverse events, including visual abnormalities, hypotension, prolonged erection, and syncope [see…
Co-administration of KALETRA with these drugs may result in an increase in PDE5 inhibitor associated adverse reactions including hypotension, syncope, visual changes and prolonged erection.
From the Sildenafil label · effective 2026-07-17
In patients taking strong CYP inhibitors such as ritonavir, sildenafil exposure is increased.
To decrease the chance of adverse reactions in patients taking ritonavir, the maximum recommended dosage and dosing frequency of SILDENAFIL ORAL FILM is 25 mg once in a 48-hour period [see Dosage and Administration ( 2.2 ), Drug Interactions ( 7.4 ), and Clinical Pharmacology ( 12.3 ) ].
Ritonavir: Do not exceed a maximum single dose of 25 mg in a 48- hour period.
Adverse Reactions with the Concomitant Use of Ritonavir The concomitant administration of the protease inhibitor ritonavir substantially increases serum concentrations of sildenafil (11-fold increase in AUC).
CYP3A4 inhibitors (e.g., ritonavir, ketoconazole, itraconazole, erythromycin) increase SILDENAFIL ORAL FILM 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.