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Nelfinavir Oral Powder and Tegretol

Determining the interaction of Nelfinavir Oral Powder and Tegretol and the possibility of their joint administration.

Check result:
Nelfinavir Oral Powder <> Tegretol
Relevance: 22.09.2022 Reviewer: Shkutko P.M., M.D., in

In the database of official manuals used in the service creation an interaction registered by statistical results of studies was found, which can either lead to negative consequences for the patient health or strengthen a mutual positive effect. A doctor should be consulted to address the issue of joint drug administration.

Consumer:

Talk to your doctor before using nelfinavir together with carBAMazepine. Combining these medications may decrease the blood levels of nelfinavir, which may reduce its effectiveness in treating HIV infection. At the same time, nelfinavir may cause the blood levels of carBAMazepine to increase. You may be more likely to experience side effects of carBAMazepine such as headache, dizziness, nausea, slurred speech, vision problems, tremors, and incoordination. Your doctor may be able to prescribe alternatives that do not interact, or you may need a dose adjustment or more frequent monitoring by your doctor to safely use both medications. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.

Professional:

GENERALLY AVOID: Coadministration of nelfinavir and carbamazepine may result in decreased plasma concentrations of nelfinavir and increased plasma concentrations of carbamazepine. The proposed mechanism involves carbamazepine induction of nelfinavir metabolism via CYP450 3A4 and, conversely, nelfinavir inhibition of carbamazepine metabolism via the same enzymatic pathway. No data are available from pharmacokinetic studies. In one case report, a 50-year-old HIV-positive male who had been stabilized on carbamazepine 400 mg three times a day developed excessive drowsiness and became unsteady on his feet three days after starting nelfinavir 1250 mg twice daily as part of a new antiretroviral regimen, along with lamivudine and tenofovir. His serum carbamazepine level was 15 mg/L, which was a 53% increase from three weeks prior when it was 9.8 mg/L. Symptoms resolved within 24 hours after the carbamazepine dosage was reduced to 400 mg twice daily, and carbamazepine level was at 9.3 mg/L two days later.

MANAGEMENT: Given the lack of pharmacokinetic data and the risk of reduced viral susceptibility and resistance development associated with subtherapeutic antiretroviral drug levels, it may be preferable to avoid using nelfinavir in combination with carbamazepine. Caution is advised if concomitant use is required. In patients already receiving nelfinavir as part of their HIV treatment regimen, close clinical and laboratory monitoring of antiretroviral response is recommended following the addition or discontinuation of carbamazepine. Likewise, if nelfinavir is added to stable carbamazepine therapy, serum drug levels and pharmacologic effects should be closely monitored and the carbamazepine dosage adjusted accordingly. Patients should be advised to contact their doctor if they develop signs of carbamazepine toxicity such as ataxia, disorientation, dizziness, nausea, vomiting, and visual disturbances.

References
  • Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0
  • "Product Information. Viracept (nelfinavir)." Agouron Pharma Inc, La Jolla, CA.
  • Bates DE, Herman RJ "Carbamazepine toxicity induced by lopinavir/ritonavir and nelfinavir." Ann Pharmacother 40 (2006): 1190-5
  • Brooks J, Daily J, Schwamm L "Protease inhibitors and anticonvulsants." AIDS Clin Care 9 (1997): 87,90
  • Canadian Pharmacists Association "e-CPS. Available from: URL: http://www.pharmacists.ca/function/Subscriptions/ecps.cfm?link=eCPS_quikLink."
Nelfinavir Oral Powder

Generic Name: nelfinavir

Brand name: Viracept

Synonyms: Nelfinavir

Tegretol

Generic Name: carbamazepine

Brand name: Carbatrol, Epitol, Equetro, Tegretol, Tegretol XR, Tegretol, Tegretol XR

Synonyms: n.a.

In the course of checking the drug compatibility and interactions, data from the following reference sources was used: Drugs.com, Rxlist.com, Webmd.com, Medscape.com.

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