ess than 30 ml/min the dose should be reduced by 75%.
Erythromycin, itraconazole
Ritonavir dosed as a pharmacokinetic enhancer or as an antiretroviral agent inhibits CYP3A4 and as a result is expected to increase the plasma concentrations of erythromycin and itraconazole. Careful monitoring of therapeutic and adverse effects is recommended when erythromycin or itraconazole is used concomitantly administered with ritonavir.
Ketoconazole
200 daily
500 q12h
↑ 3.4-fold
↑ 55%
Ritonavir inhibits CYP3A-mediated metabolism of ketoconazole. Due to an increased incidence of gastrointestinal and hepatic adverse reactions, a dose reduction of ketoconazole should be considered when co-administered with ritonavir dosed as an antiretroviral agent or as a pharmacokinetic enhancer.
Sulfamethoxazole/Trimethoprim2
800/160, single dose
500 q12h
20% / ↑ 20%
↔
Dose alteration of sulfamethoxazole/trimethoprim during concomitant ritonavir therapy should not be necessary.
Antipsychotics/Neuroleptics
Clozapine, pimozide
Ritonavir co-administration is likely to result in increased plasma concentrations of clozapine or pimozide and is therefore contraindicated (see section 4.3).
Haloperidol, risperidone, thioridazine
Ritonavir dosed as an antiretroviral agent is likely to inhibit CYP2D6 and as a result is expected to increase concentrations of haloperidol, risperidone and thioridazine. Careful monitoring of therapeutic and adverse effects is recommended when these medicines are concomitantly administered with antiretroviral doses of ritonavir (see section 4.3).
β2-agonist (long acting)
Salmetarol
Ritonavir inhibits CYP3A4 and as a result a pronounced increase in the plasma concentrations of salmetarol is expected. Therefore concomitant use is not recommended.
Calcium channel antagonists
Amlodipine, diltiazem, nifedipine
Ritonavir dosed as a pharmacokinetic enhancer or as an antiretroviral agent inhibits CYP3A4 and as a result is expected to increase the plasma concentrations of calcium channel antagonists. Careful monitoring of therapeutic and adverse effects is recommended when these medicines are concomitantly administered with ritonavir.
Endothelin antagonists
Bosentan
Co-administration of bosentan and ritonavir may increase steady state bosentan maximum concentr ations (Cmax) and area under the curve (AUC).
Ergot Derivatives
Dihydroergotamine, ergonovine, ergotamine, methylergonovine
Ritonavir co-administration is likely to result in increased plasma concentrations of ergot derivatives and is therefore contraindicated (see section 4.3).
GI motility agent
Cisapride
Ritonavir co-administration is likely to result in increased plasma concentrations of cisapride and is therefore contraindicated (see section 4.3).
HMG Co-A Reductase Inhibitors
Atorvastatin, Fluvastatin, Lovastatin, Pravstatin, Rosuvastatin, Simvastatin
HMG-CoA reductase inhibitors which are highly dependent on CYP3A metabolism, such as lovastatin and simvastatin, are expected to have markedly increased plasma concentrations when co-administered with ritonavir dosed as an antiretroviral agent or as a pharmacokinetic enhancer. Since increased concentrations of lova |
