tromethamine
tromethamine
[tro-meth´ah-mēn]tromethamine
Pharmacologic class: Protein substrate
Therapeutic class: Systemic alkalizer
Pregnancy risk category C
Action
Combines with hydrogen ions to form bicarbonate and a buffer, correcting acidosis. Also shows some diuretic activity.
Availability
Injection: 18 g/500 ml
Indications and dosages
➣ Metabolic acidosis associated with cardiac bypass surgery
Adults: 9 ml/kg (0.32 g/kg) by slow I.V. infusion; 500 ml (18 g) is usually adequate. Maximum single dosage is 500 mg/kg infused over at least 1 hour.
➣ Metabolic acidosis associated with cardiac arrest
Adults: 3.6 to 10.8 g by I.V. injection into large peripheral vein if chest isn't open, or 2 to 6 g I.V. directly into ventricular cavity if chest is open. After reversal of cardiac arrest, patient may need additional amounts to control persistent acidosis.
➣ To correct acidity of acid-citrate-dextrose (ACD) blood in cardiac bypass surgery
Adults: 0.5 to 2.5 g added to each 500 ml of ACD blood used for priming pump-oxygenator. Usual dosage is 2 g.
Dosage adjustment
• Elderly patients
Contraindications
• Hypersensitivity to drug
• Anuria
• Uremia
Precautions
Use cautiously in:
• renal disease, severe respiratory disease, respiratory depression
• pregnant patients
• infants.
Administration
See Keep intubation equipment nearby in case respiratory depression occurs.
• For metabolic acidosis associated with cardiac bypass surgery, give by slow I.V. infusion through large-bore I.V. catheter into large antecubital vein. Elevate arm after infusion.
• If extravasation occurs, discontinue drug and infiltrate affected area with 1% procaine hydrochloride (containing hyaluronidase).
• Be aware that in cardiac arrest, drug is used with standard resuscitative measures. When giving by direct I.V. injection into open chest, never inject into cardiac muscle.
Adverse reactions
GU: oliguria
Hepatic: hemorrhagic hepatic necrosis
Metabolic: metabolic alkalosis, transient hypoglycemia, fluid-solute overload, hyperkalemia
Respiratory: respiratory depression
Other: fever; I.V. site infection; extravasation with venous thrombosis or phlebitis, inflammation, necrosis, and sloughing
Interactions
Drug-diagnostic tests. Glucose: decreased level
Potassium: increased level
Patient monitoring
• Maintain continuous cardiac monitoring.
• Monitor arterial blood gas levels. Watch for alkalosis and signs and symptoms of respiratory depression.
• Assess liver function tests. Stay alert for signs and symptoms of hepatic impairment.
• Monitor glucose and potassium levels. Watch for hypoglycemia and hyperkalemia.
• Closely monitor fluid intake and output. Check for fluid and electrolyte imbalances and oliguria related to hyperkalemia.
Patient teaching
• Explain drug therapy to patient. Assure him he will be monitored continuously.
• As appropriate, review all significant and life-threatening adverse reactions and interactions, especially those related to the tests mentioned above.