tromethamine

tromethamine

 [tro-meth´ah-mēn]

an alkalizer used intravenously in treatment of metabolic acidosis. It is also used to make buffer solutions.

tromethamine

Tham

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

☞ 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.

tro·meth·a·mine

(trō-meth'ă-mēn),

A weakly basic compound used as an alkalizing agent and as a buffer in enzymic reactions.

Synonym(s): tris(hydroxymethyl)aminomethane, tris(hydroxymethyl)methylamine