THAM-E
Clinical safety rating: caution
Comprehensive clinical and safety monograph for THAM-E (THAM-E).
THAM-E (tromethamine) is a sodium-free organic amine that acts as a proton acceptor, buffering excess hydrogen ions in metabolic acidosis. It increases bicarbonate concentration by reducing carbon dioxide tension and enhances renal excretion of hydrogen ions.
| Metabolism | Primarily excreted unchanged by the kidneys; minimal hepatic metabolism. |
| Excretion | Renal: >95% as unchanged drug; <5% metabolized or excreted in bile/feces. |
| Half-life | Terminal elimination half-life: 5-10 minutes (2-3 minutes for distribution phase). Clinically negligible accumulation with repeat doses due to rapid renal clearance. |
| Protein binding | <10% bound to plasma proteins (albumin). |
| Volume of Distribution | 0.4-1.0 L/kg (distributes primarily in extracellular fluid; minimal intracellular penetration). |
| Bioavailability | Intravenous only; oral bioavailability negligible due to gastric inactivation. |
| Onset of Action | Intravenous: immediate buffering effect within seconds to minutes. |
| Duration of Action | 30-60 minutes for single dose; prolonged in renal impairment. Duration depends on continued acid production and renal function. |
Intravenous: Initial dose (mL of 0.3 M solution) = body weight (kg) × base deficit (mEq/L) × 1.1. Administer by slow IV infusion, not to exceed 8 mL/kg/hour. Maximum single dose: 48 mL/kg.
| Dosage form | INJECTABLE |
| Renal impairment | Contraindicated in anuria and severe renal impairment (GFR <15 mL/min). For GFR 15-29 mL/min, reduce dose by 50% and monitor serum electrolytes. No adjustment for GFR ≥30 mL/min. |
| Liver impairment | No specific dosing adjustments for hepatic impairment. Monitor electrolytes and acid-base status closely in patients with hepatic encephalopathy. |
| Pediatric use | Initial dose (mL) = body weight (kg) × base deficit (mEq/L) × 1.1. Maximum infusion rate: 2 mL/kg/hour. Titrate based on arterial blood gas monitoring. |
| Geriatric use | Use with caution due to increased risk of fluid overload and electrolyte disturbances. Reduce initial dose by 50% and monitor cardiopulmonary status. Infusion rate not to exceed 4 mL/kg/hour. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for THAM-E (THAM-E).
| Breastfeeding | Excretion into human milk unknown. Caution advised. No M/P ratio available. |
| Teratogenic Risk | No controlled studies in pregnant women. Animal reproduction studies have not been conducted. Use during pregnancy only if clearly needed. First trimester: potential risk unknown; second/third trimester: may cause maternal alkalosis and fetal metabolic alkalosis if used to correct metabolic acidosis. |
| Fetal Monitoring |
■ FDA Black Box Warning
None
| Serious Effects |
Anuria or uremia, hypocalcemic tetany, chronic respiratory acidosis with hypoxemia, and alkalosis (metabolic or respiratory).
| Precautions | Risk of respiratory depression due to decreased CO2 tension; monitor arterial blood gases. Use with caution in renal impairment, severe hepatic disease, or neonates (may cause muscle necrosis). Can cause hypoglycemia and hyperkalemia when given rapidly. |
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| Monitor maternal serum electrolytes (particularly potassium, calcium, glucose), acid-base status, and renal function. Monitor fetal heart rate and uterine activity if used in preterm labor or during delivery. |
| Fertility Effects | No data on effects on fertility. Animal studies not performed. |