c effect. Doses of ritonavir less than 200 mg twice daily should not be used with tipranavir as they might alter the efficacy of the combination. For further information, physicians should refer to the Aptivus Summary of Product Characteristics.
ND: Not determined.
1. Based on cross-study comparison to 400 mg atazanavir once daily alone.
2. Based on cross-study comparison to 1200 mg amprenavir twice daily alone.
3. Based on cross-study comparison to 800 mg indinavir three times daily alone.
4. Based on cross-stud y comparison to 600 mg saquinavir three times daily alone.
Medicinal Product Interactions – Ritonavir with Antiretroviral Agents Other Than Protease Inhibitors
Co-administered Medicinal Product
Dose of Co-administered Medicinal Product (mg)
Dose of NORVIR (mg)
Medicinal Product Assessed
AUC
Cmin
Didanosine
200 q12h
600 q12h 2 h later
Didanosine
13%
↔
As ritonavir is recommended to be taken with food and didanosine should be taken on an empty stomach, dosing should be separated by 2.5 h. Dose alterations should not be necessary.
Delavirdine
400 q8h
600 q12h
Delavirdine1
↔
↔
Ritonavir
↑ 50%
↑ 75%
Based on comparison to historical data, the pharmacokinetics of delavirdine did not appear to be affected by ritonavir. When used in combination with delavirdine, dose reduction of ritonavir may be considered.
Efavirenz
600 q24h
500 q12h
Efavirenz
↑ 21%
Ritonavir
↑ 17%
A higher frequency of adverse reactions (eg, dizziness, nausea, paraesthesia) and laboratory abnormalities (elevated liver enzymes) have been observed when efavirenz is co-administered with ritonavir dosed as an antiretroviral agent.
Maraviroc
100 q12h
100 q12h
Maraviroc
↑161%
↑28%
Ritonavir increases the serum levels of maraviroc as a result of CYP3A inhibition. Maraviroc may be given with ritonavir to increase the maraviroc exposure. For further information, refer to the Summary of Product Characteristics for Celsentri.
Nevirapine
200 q12h
600 q12h
Nevirapine
↔
↔
Ritonavir
↔
↔
Co-administration of ritonavir with nevirapine does not lead to clinically relevant changes in the pharmacokinetics of either nevirapine or ritonavir.
Zidovudine
200 q8h
300 q6h
Zidovudine
25%
ND
Ritonavir may induce the glucuronidation of zidovudine, resulting in slightly decreased levels of zidovudine. Dose alterations should not be necessary.
ND: Not determined
1. Based on parallel group comparison.
Ritonavir effects on Non-antiretroviral Co-administered Medicinal Products
Co-administered Medicinal Products
Dose of Co-administered Medicinal Products (mg)
Dose of NORVIR (mg)
Effect on Co-administered Medicinal Products AUC
Effect on Co-administered Medicinal Products Cmax
Alpha1-Adrenoreceptor Antagonist
Alfuzosin
Riton |
