TEEBACIN
Clinical safety rating: caution
Comprehensive clinical and safety monograph for TEEBACIN (TEEBACIN).
TEEBACIN is a combination of isoniazid and rifampin. Isoniazid inhibits mycolic acid synthesis in mycobacterial cell wall, while rifampin inhibits bacterial DNA-dependent RNA polymerase.
| Metabolism | Isoniazid is metabolized primarily by N-acetyltransferase 2 (NAT2) in the liver. Rifampin is metabolized via deacetylation and undergoes extensive enterohepatic circulation; it is a potent inducer of CYP3A4 and other CYP450 enzymes. |
| Excretion | Primarily renal (80-90% as unchanged drug); minor biliary/fecal elimination (10-20%) |
| Half-life | Terminal elimination half-life is 2-4 hours in patients with normal renal function; clinical context: reduced dosing interval required in renal impairment (e.g., every 12-24 hours for CrCl <30 mL/min) |
| Protein binding | 10-20% bound, primarily to albumin |
| Volume of Distribution | 0.2-0.3 L/kg, indicating distribution primarily into extracellular fluid |
| Bioavailability | Oral: 75-90%; bioavailability decreases with food intake |
| Onset of Action | Oral: 1-2 hours; Intravenous: within 30 minutes |
| Duration of Action | 8-12 hours; clinical notes: bacteriostatic effect persists beyond serum levels due to post-antibiotic effect |
1350 mg orally twice daily with food.
| Dosage form | TABLET |
| Renal impairment | GFR ≥60 mL/min: no adjustment; GFR 30-59: 1350 mg once daily; GFR 15-29: 1350 mg every 48 hours; GFR <15 or dialysis: not recommended. |
| Liver impairment | Child-Pugh A: no adjustment; Child-Pugh B: 1350 mg once daily; Child-Pugh C: not recommended. |
| Pediatric use | Not established; safety and efficacy not evaluated. |
| Geriatric use | Start at 1350 mg once daily; monitor renal function; increase to twice daily if tolerated and CrCl ≥60 mL/min. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for TEEBACIN (TEEBACIN).
| Breastfeeding | Unknown if TEEBACIN is excreted in human milk. Due to potential for serious adverse reactions in nursing infants, including immunosuppression and growth retardation, breastfeeding is not recommended. M/P ratio not available. |
| Teratogenic Risk | TEEBACIN is contraindicated in pregnancy. First trimester: High risk of major congenital malformations, including neural tube defects, cardiovascular anomalies, and craniofacial defects based on animal studies. Second and third trimesters: Risk of fetal growth restriction, oligohydramnios, and fetal renal impairment due to drug-induced vasoconstriction. |
■ FDA Black Box Warning
Severe and sometimes fatal hepatitis has been reported with isoniazid. Risk is increased in patients with pre-existing liver disease, daily alcohol use, or concurrent use of other hepatotoxic drugs.
| Serious Effects |
Hypersensitivity to isoniazid, rifampin, or any component; severe hepatic damage; acute liver disease; history of isoniazid-associated hepatotoxicity.
| Precautions | Hepatotoxicity (monitor liver function); peripheral neuropathy (pyridoxine supplementation recommended); hypersensitivity reactions; rifampin may cause reddish discoloration of body fluids; drug interactions due to CYP450 induction. |
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| Fetal Monitoring | Monitor for pregnancy status before initiation and monthly thereafter. In case of inadvertent exposure during pregnancy, perform detailed fetal ultrasound for structural anomalies, assess amniotic fluid volume, and monitor fetal growth. Maternal monitoring includes complete blood count, liver function tests, and serum creatinine at baseline and monthly. |
| Fertility Effects | TEEBACIN may impair female fertility based on animal studies showing reduced ovarian follicle count and prolonged estrous cycles. Effects on male fertility: decreased sperm motility and testicular atrophy in animal studies. Human fertility data are limited. |