It is assumed that the use of ritonavir andriol in combination with fusidic acid increases the concentration of both fusidic acid and ritonavir as protease inhibitor in the plasma. St. John’s wort (Hypericum perforatum): should not be taken in combination with ritonavir as ritonavir plasma concentrations fall . This is due to the induction SYR3A4, resulting in decreased therapeutic efficacy and develops resistance to ritonavir. Indinavir: . Ritonavir inhibits indinavir metabolism flowing with and increases indinavir plasma concentrations risk nephrolithiasis can be increased at doses of indinavir equal to or higher than 800 mg twice daily in combination with ritonavir. It is necessary to maintain adequate hydration of patients and carrying out monitoring of their condition.
Ketoconazole: the use of ritonavir in combination with ketoconazole was reflected in a marked rise in plasma levels of ketoconazole: mean increased by 244% and Cmax by 55%. The average elimination half ketoconazole increased from 2.7 to 13.2 hours. The average values of and Cmax of ritonavir increased by 18% and 10%, respectively.
The doses of ritonavir does not need to be adjusted while taking ketoconazole, while the dose of ketoconazole 200 mg / day and above should not be used in combination with ritonavir. It is recommended to reduce the dose of ketoconazole. Methadone: the andriol use of ritonavir in combination with methadone resulted in a decrease of methadone concentrations. You may need to increase the dose of methadone during its use in combination with ritonavir. Nelfinavir: the interaction between ritonavir and nelfinavir probably occurs as to the inhibition or induction of cytochrome P450. Simultaneously with a significant increase in the concentration M8 (major active metabolite of nelfinavir), the concentration of nelfinavir increases slightly. Contraceptive preparations for oral administration: the use of ritonavir in combination with a fixed dose of estrogen expressed in reducing the mean AUC of ethinyl estradiol is 32% and the C max – 40% . Use contraceptive preparations with a higher concentration of ethinyl estradiol, or use alternative methods of contraception.
Rifabutin: applications andriol in combination with ritonavir results in multiple (4 to 35 times) increase in AUC and Cmax of rifabutin and its active metabolite 25-O-desacetyl rifabutin that has clinical implications.Recommended dose reduction rifabutin, at least 3/4 of the usual daily dose of 300 mg (i.e. 150 mg every other day or three times a week). Further reducing the dose recommended, if necessary. Saquinavir:data pharmacokinetics studies in patients indicate that its use in combination with ritonavir causes multiple increase saquinavir equilibrium levels in blood (AUC, a 17-fold increase). Long-term combination therapy at doses of 400 mg twice a day, each preparation was accompanied by an increase in the frequency of adverse reactions. Sildenafil: it is recommended not to prescribe sildenafil to patients taking ritonavir. Admission of sildenafil in combination with ritonavir caused a significant (11-fold) increase in sildenafil plasma AUC, and therefore increases the risk of side effects associated with sildenafil, such as hypotension, syncope, visual impairment and prolonged andriol erection. generic labs