TROMETHAMINE
Clinical safety rating: caution
Comprehensive clinical and safety monograph for TROMETHAMINE (TROMETHAMINE).
Tromethamine is a proton acceptor that buffers hydrogen ions, correcting metabolic acidosis by increasing bicarbonate and base excess. It acts as a weak base with high buffering capacity.
| Metabolism | Tromethamine is not metabolized; it is primarily excreted unchanged by the kidneys. |
| Excretion | Renal excretion of unchanged drug: >95%. Negligible biliary or fecal elimination. |
| Half-life | Terminal elimination half-life: 2–3 hours in adults with normal renal function. May be prolonged in renal impairment. |
| Protein binding | <10% bound to plasma proteins (albumin). |
| Volume of Distribution | 0.3–0.4 L/kg; primarily distributes in extracellular fluid. |
| Bioavailability | Not available (administered intravenously only; oral bioavailability is negligible due to lack of absorption). |
| Onset of Action | Intravenous: Within minutes (immediate buffering effect). |
| Duration of Action | Intravenous: 30–60 minutes for pH correction; may persist longer in impaired renal function. Multiple doses may be needed for sustained effect. |
| Molecular Weight | 121.14 |
Intravenous: 1 M solution (3.6 g/30 mL) administered via central line; usual adult dose 300-500 mg/kg (0.27-0.45 g/kg) given over 1-2 hours; may be repeated based on blood gas monitoring.
| Dosage form | SOLUTION |
| Renal impairment | Contraindicated in anuria or severe renal impairment (GFR < 30 mL/min). Use with caution in renal insufficiency; monitor acid-base balance. No specific dose adjustment guidelines; avoid in renal failure. |
| Liver impairment | No specific Child-Pugh based dose adjustments; use with caution in hepatic impairment as metabolism is minimal (primarily renal excretion). Monitor electrolytes and pH. |
| Pediatric use | Intravenous: 1 M solution; dose based on calculated base deficit: mL of 0.3 M THAM = body weight (kg) × base deficit (mEq/L) × 1.1. Administer over 1-2 hours via central line. Maximum infusion rate: 5 mL/kg/hour. |
| Geriatric use | No specific dose adjustment; monitor renal function and avoid in geriatric patients with renal impairment due to decreased creatinine clearance. Use lower end of dosing range and monitor acid-base status frequently. |
| 1st trimester | Limited human data; animal studies not available. Use only if clearly needed. |
| 2nd trimester | Limited human data; may cause fluid and electrolyte disturbances. Use only if clearly needed. |
| 3rd trimester | Limited human data; may cause metabolic alkalosis. Use only if clearly needed. |
Clinical note
Comprehensive clinical and safety monograph for TROMETHAMINE (TROMETHAMINE).
| Placental transfer | Crosses the placenta; may cause metabolic alkalosis in the fetus. Degree not quantified. |
| Breastfeeding | No data on excretion into breast milk. Use with caution in nursing mothers, especially if neonatal acidosis or fluid/electrolyte imbalances are of concern. |
| Lactation Rating |
■ FDA Black Box Warning
There is no FDA black box warning for tromethamine.
| Serious Effects |
Hypersensitivity to tromethamineAnuria or uremiaChronic respiratory acidosisAlkalosis (metabolic or respiratory)Hypocalcemia (may cause tetany)
| Precautions | Monitor blood pH, pCO2, and electrolytes (especially potassium) during infusion, Use with caution in patients with renal impairment due to risk of accumulation, May cause respiratory depression, especially in patients with impaired renal function, Avoid extravasation due to tissue necrosis, Not recommended for neonatal use due to risk of hyperosmolality |
| Food/Dietary | No known food interactions. However, electrolyte imbalances (e.g., hypokalemia) may be affected by dietary potassium intake; maintain a balanced diet per clinician advice. |
Loading safety data…
| L3 (Limited Data) |
| Teratogenic Risk | Tromethamine is a parenteral alkalinizing agent used in metabolic acidosis. Animal reproduction studies have not been conducted. It is not known whether tromethamine can cause fetal harm when administered to a pregnant woman. Use during pregnancy only if clearly needed. Risk cannot be ruled out. |
| Fetal Monitoring | Monitor arterial blood gases, serum electrolytes (especially potassium and calcium), blood glucose, and renal function. Observe for signs of respiratory depression, hypoglycemia, and hyperkalemia. |
| Fertility Effects | No studies on fertility effects are available. No known impact on human fertility. |
| Clinical Pearls | Tromethamine (THAM) is an amino alcohol that acts as a proton acceptor, used to correct metabolic acidosis when sodium bicarbonate is contraindicated (e.g., hypernatremia, hypercapnia). It is preferred in patients with lactic acidosis or respiratory acidosis because it does not generate CO2. Monitor serum potassium closely as it can cause hypokalemia. Extravasation causes tissue necrosis; administer via central line if possible. Correct dosing is based on base deficit: mL of 0.3 M THAM = base deficit (mEq/L) × weight (kg) × 1.1. |
| Patient Advice | This medication is used to treat acidosis (too much acid in the blood). · It is given intravenously (IV) by your healthcare provider. · Report any signs of IV site reaction: pain, redness, swelling, or blistering. · You may need frequent blood tests to monitor your acid-base balance and potassium levels. · Tell your doctor if you have kidney disease or low blood potassium before treatment. |