Peptisolv IV Drug Interactions

Effects of omeprazole on pharmacokinetics of other drugs: Medicinal products with pH-dependent absorption: Absorption of medicinal products that depend on gastric pH for absorption may decrease or increase depending on the reduced gastric acidity during treatment with omeprazole.
Nelfinavir, Atazanavir: Plasma levels of atazanavir and nelfinavir decrease when used concomitantly with omeprazole.
Concomitant administration of omeprazole with nelfinavir is contraindicated. Concomitant use with omeprazole (40 mg once daily) have reduced mean nelfinavir exposure approximately by 40% and its pharmacologically active metabolite M8 mean exposure approximately by 75-90%. The interaction also involves CYP2C19 inhibition.
Concomitant use of omeprazole with nelfinavir is not recommended. In healthy volunteers, concomitant use of omeprazole (40 mg once daily) and atazanavir 300 mg/ritonavir 100 mg has reduced atazanavir exposure by 75%. Increasing atazanavir dose to 400 mg does not compensate for the impact of omeprazole on atazanavir exposure.
Co-administration of omeprazole (20 mg once daily) with atazanavir 400 mg/ritonavir 100 mg resulted in approximately 30% reduction in atazanavir exposure compared to once-daily atazanavir 300 mg/ritonavir 100 mg administration in healthy volunteers.
Digoxin: Concomitant use of Omeprazole (20 mg daily) and digoxin have increased digoxin bioavailability by 10% in healthy volunteers. Digoxin toxicity was rarely reported. However, caution must be exercised in elderly patients when omeprazole is given in high doses. Subsequently, therapeutic monitoring for digoxin should be encouraged.
Clopidogrel: Results of studies conducted on healthy volunteers showed that there is pharmacokinetic (PK)/pharmacodynamics (PD) interaction between clopidogrel (300 mg loading dose/75 mg daily maintenance dose) and omeprazole (80 mg once daily). When clopidogrel and omeprazole were co-administered, mean exposure to the active metabolite of clopidogrel was decreased by 46% and mean reduction in maximum inhibition of platelet aggregation was 16%.
In both observational and clinical studies, inconsistent data on clinical outcomes of PK/PD interaction in terms of important cardiovascular events have been reported. As a precaution, concomitant use of omeprazole and clopidogrel should be avoided.
Other medicinal products: The absorption of posaconazole, erlotinib, ketoconazole and itraconazole is significantly reduced and therefore clinical efficacy may be impaired. Concomitant use with posaconazole and erlotinib should be avoided.
Medicinal products metabolized by CYP2C19: Omeprazole is a moderate inhibitor of CYP2C19 which is the major metabolizing enzyme of omeprazole. Therefore, metabolism of other drugs metabolized by CYP2C19 enzyme, such as diazepam, phenytoin, warfarin (R-warfarin) and other vitamin K antagonists and cilostazol may be reduced.
Cilostazol: In a cross-over study with 40 mg of omeprazole given to healthy subjects, Cmax and AUC values for cilostazol were increased by 18% and 26% respectively and values for one of its active metabolites increased by 29% and 69%, respectively.
Phenytoin: Monitoring phenytoin plasma concentrations is recommended during the first two weeks after initiating omeprazole treatment; if phenytoin dose is adjusted, monitoring and further dose adjustment should be made after omeprazole treatment is ended.
Unknown mechanism: Saquinavir: Approximately 70% increase in plasma levels of saquinavir, a well-tolerated agent in HIV-infected patients, was reported with concomitant use of omeprazole and saquinavir/ritonavir.
Tacrolimus: Increased plasma levels of tacrolimus were reported with concomitant use of omeprazole and tacrolimus. Assisted monitoring of renal functions (creatinine clearance) besides tacrolimus concentrations should be performed and tacrolimus dosage should be adjusted if necessary.
Methotrexate: In some patients, increased methotrexate levels were reported when co-administered with proton pump inhibitors. Temporary discontinuation of omeprazole may be required during high-dose methotrexate administration.
Effects of other drugs on the pharmacokinetics of omeprazole: CYP2C19 and/or CYP3A4 inhibitors: Since omeprazole is metabolized by CYP2C19 and CYP3A4, drugs such as clarithromycin and voriconazole known to be inhibited by CYP2C19 or CYP3A4 or both may cause increased serum omeprazole levels by decreasing the metabolism rate of omeprazole. Concomitant use of omeprazole and voriconazole resulted in more than twofold increase in omeprazole exposure. Dose adjustment for omeprazole is not required during short-term concomitant use since omeprazole is well tolerated at high doses. However, dose adjustment should be considered in patients with severe hepatic impairment and if long-term treatment is necessary.