Lopinavir / ritonavir

Carbamazepine

Not recommended association.

No pharmaceutical opinion available for this interaction.

Mechanism

Lopinavir / ritonavir may possibly inhibit the metabolism (CYP 3A4) and consequently increase the plasma concentration of Carbamazepine.

Carbamazepine can induce the metabolism (CYP 3A4) and decrease the plasma concentration of Lopinavir / ritonavir.

Lopinavir / ritonavir

Pharmacodynamic effects

Possible decrease of clinical efficacy.

Recommendations

An increase in dosage may be necessary.

Monitor for signs and symptoms of therapeutic failure.

For lopinavir/ritonavir, BID dosage is recommended. Avoid QD dosage.

Alternative solution(s)

Carbamazepine

Pharmacodynamic effects

Possible increase of adverse effects.

Recommendations

Avoid if possible. Use an alternative or monitor patient closely.

A reduction in dosage may be necessary.

It is suggested to decrease 25-50% the dodage of carbamazepin . Dosage of carbamazepin 3-5 days following the introduction of lopinavir/ritonavir.

Alternative solution(s)

Gabapentin, pregabaline, leviracetam.

Monitor

Carbamazepine adverse effects : disorientation, ataxia, lethargy, drowsiness, nausea, vomiting, headache, diplopia, dizziness, leukopenia and hyponatremia.

Tests

Carbamazepine

Lopinavir plasma level

CD4+

Viral load HIV

Pharmacokinetic parameters
Parameters
Reference number
# patients
HIV
Dose
Frequency
Duration (days)
Concentration
Lopinavir / ritonavir
2090
1
+
400/100 mg
BID
9
 
Carbamazepine
2090
1
+
400 mg
TID
210
+ 46%
Comment

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. See ritonavir + carbamazepine.

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.

Reference
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    Lopinavir/ritonavir (Kaletra). Coorporation Abbvie, Quebec, Canada, 5 oct 2017.
  • 122
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  • 2988
    Carbamazepine (Tegretol), Novartis Pharma, Québec, Canada, 4 mai 2018.
  • 1304
    Kato Y, Fujii T, Mizoguchi N, et al. Potential interaction between ritonavir and carbamazepine. Pharmacother 2000;20(7):851-854.
  • 2090
    Bates D and Herman RJ. Carbamazepine Toxicity Induced by Lopinavir/Ritonavir and Nelfinavir. Ann Pharmacother 2006;40:1190-1195.
  • 717
    Mateu-de Antonio J, Grau S, Gimeno-Bayon JL, Carmona A. Ritonavir-induced carbamazepine toxicity. Ann Pharmcother 2001;35:125-126.
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    Garcia AB, Ibarra AL, Etessam JP, et al. Protease inhibitor-induced carbamazepine toxicity. Clin Neuropharmacol 2000;23(4):216-218.
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    Liedtke MD, Lockhart SM, and Rathbun RC. Anticonvulsivant and antiretroviral interactions. Ann Pharmacother 2004;38:482-489.
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