Co-administration of pantoprazole is not recommended with HIV protease inhibitors for which absorption is dependent on acidic intragastric pH such as atazanavir, due to significant reduction in their bioavailability. If unavoidable close clinical monitoring (e.g. virus load) is recommended and a dose of 20 mg per day should not be exceeded. Dosage of the HIV protease inhibitor may need to be adjusted.
Inhibitors of CYP2C19 (e.g. fluvoxamine) could increase the systemic exposure of pantoprazole. A dose reduction may be considered for patients treated long-term with high doses of pantoprazole, or those with hepatic impairment. Enzyme inducers affecting CYP2C19 and CYP3A4 such as rifampicin and St John´s wort (Hypericum perforatum) may reduce the plasma concentrations of pantoprazole.
With respect to association with infrequent cases of subacute cutaneous lupus erythematosus (SCLE): if lesions occur, especially in sun exposed areas of the skin, and if accompanied by arthralgia, the patient should seek medical help promptly and the healthcare professional should consider stopping pantoprazole. SCLE after previous treatment with a proton pump inhibitor may increase the risk of SCLE with other proton pump inhibitors.