Acetazolamide-induced interference with primidone absorption. Case reports and metabolic studies

Area of Science:

• Pharmacology
• Clinical Pharmacy

Background:

• Primidone is an anticonvulsant medication.
• Acetazolamide is a carbonic anhydrase inhibitor used for various conditions.

Observation:

• The study investigated the interaction between acetazolamide and primidone in three patients.
• Plasma levels and urinary excretion of primidone and its metabolites were monitored.

Findings:

• A significant drug interaction was observed in two out of three patients.
• In one patient, primidone was not detected in plasma when taken with acetazolamide.
• Another patient experienced delayed peak plasma concentrations and excretion of primidone and its metabolites, phenylethylmalonamide and phenobarbital.

Implications:

• Concurrent administration of acetazolamide and primidone may alter primidone pharmacokinetics.
• Clinicians should be aware of this potential interaction when prescribing these medications together.
• Further research may be warranted to elucidate the mechanism and clinical significance of this interaction.