Pregabalin Use with Tuberculosis Medications
Pregabalin can be safely used with standard TB medications including rifampicin without dose adjustment, as pregabalin is renally excreted and not metabolized by cytochrome P450 enzymes that rifampicin induces. 1
Key Pharmacokinetic Considerations
Pregabalin undergoes minimal metabolism and is primarily eliminated unchanged through renal excretion, making it immune to the extensive enzyme induction caused by rifampicin 1
Rifampicin induces CYP1A2, 2B6, 2C8, 2C9, 2C19, 3A4, UDP-glucuronyltransferases, sulfotransferases, carboxylesterases, P-glycoprotein, and MRP2 1, but pregabalin does not rely on any of these pathways for elimination
This contrasts sharply with medications like lamotrigine (which requires dose doubling with rifampicin due to glucuronidation induction) 2 or antiretrovirals that require complex dose adjustments 3, 4
Standard TB Treatment Regimen
The preferred regimen is rifampicin, isoniazid, pyrazinamide, and ethambutol for 2 months, followed by rifampicin and isoniazid for 4 months 3, 1, 5
Rifampicin 10 mg/kg daily (maximum 600 mg/day) should not be compromised to accommodate drug interactions, as effective TB treatment is critical for morbidity and mortality outcomes 3, 1
Monitoring Considerations for TB Treatment
While pregabalin itself requires no special monitoring when combined with TB medications, standard TB treatment monitoring applies:
Baseline hepatic enzymes, bilirubin, serum creatinine, complete blood count, and platelet count should be obtained in adults 3
Monthly clinical assessment focusing on symptoms of hepatotoxicity (fever, malaise, vomiting, jaundice, abdominal pain, darkened urine) 3, 1
Peripheral neuropathy prevention with pyridoxine 10 mg daily is recommended for patients with diabetes, alcoholism, HIV, chronic renal failure, or malnutrition taking isoniazid 3
Critical Pitfalls to Avoid
Do not confuse pregabalin with gabapentin - while both are renally excreted, always verify the specific medication being prescribed
Do not assume all neuropathic pain medications behave similarly with rifampicin - many antiepileptics (like lamotrigine, carbamazepine, phenytoin) have significant interactions requiring dose adjustments 2
Never discontinue or reduce rifampicin dosing to avoid perceived drug interactions unless there is documented evidence of a clinically significant interaction 3, 1
Rifampicin causes orange-red discoloration of urine, sweat, tears, and saliva - counsel patients that this is expected and does not indicate a problem 1
Special Populations
Renal impairment: Both pregabalin and certain TB medications (ethambutol, streptomycin) require dose adjustment in renal failure 3, but this is independent of any drug-drug interaction
Hepatic disease: Monitor liver function closely during TB treatment, as rifampicin, isoniazid, and pyrazinamide are all potentially hepatotoxic 3