No pharmaceutical opinion available for this interaction.
Carbamazepine can induce the metabolism (CYP 3A4) and decrease the plasma concentration of Ritonavir.
Ritonavir may possibly inhibit the metabolism (CYP 3A4) and consequently increase the plasma concentration of Carbamazepine.
3A4 and 2D6 (major), 1A2 and 2B6 (minor), 5 metabolites, one of which has a weak concentration of an active metabolite (M-2), transporters: MRP1, MRP2, P-gp
2B6, 2C8, 2C9, 1A2, 2C19 (moderate) UGT (moderate)
3A4 (potent) and 2D6 (moderate), transporters: BCRP, OATP1A2, OATP1B1, OATP1B3, MRP1, MRP2, OCT1, OCT2, P-gp
Possible decrease of clinical efficacy.
Therefore, resulting in loss of therapeutic effect of associated IP.
Monitor for signs and symptoms of therapeutic failure.
3A4 (main), 2C8, 1A2; Active metabolite: epoxide hydrolase (CBZ-10,11- epoxide)
3A4 (potent), 2C9, 2C19, P-gp, UGT and possibly 1A2
Possible increase of adverse effects.
Avoid association. Choose an alternative.
Monitor closely for side effects.
A reduction in dosage may be necessary.
Gabapentin, pregabaline, leviracetam.
Carbamazepine adverse effects : disorientation, ataxia, lethargy, drowsiness, nausea, vomiting, headache, diplopia, dizziness, leukopenia and hyponatremia.
Viral load HIV
Associated PI plasma level
Ref #1304 : Reported case of a 20-year-old patient who developed vomiting, dizziness, elevated liver enzymes, and increased carbamazepine concentration by 87% following the addition of one dose of ritonavir 200 mg. Symptoms started within 12 hours after the first dose of ritonavir. In order to obtain a concentration within the therapeutic index, the dose of carbamazepine was reduced from 750 to 280 mg QD. Several other cases of acute toxicity to carbamazepine 2 to 4 days after the addition of ritonavir have been reported.
Ref #2090: Another case reported of a 50 year man who developed excessive drowsiness following the introduction of lopinavir/ritonavir and it was found that his serum carbamazepine concentration had increased by 46%. His antiretroviral therapy was then changed to nelfinavir 1250 mg BID but 3 days later the same symptoms appeared with 53% increase in carbamazepine. The symptoms of carbamazepine toxicity disappeared after a carbamazepine dose reduction of 33%. See lopinavir/ritonavir + carbamazepine.