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Tromethamine

Pronunciation

(troe METH a meen)

Index Terms

  • Tris Buffer
  • Tris(hydroxymethyl)aminomethane

Dosage Forms

Excipient information presented when available (limited, particularly for generics); consult specific product labeling.

Solution, Intravenous:

Tham: 30 mEq/100 mL (500 mL)

Brand Names: U.S.

  • Tham

Pharmacologic Category

  • Alkalinizing Agent, Parenteral

Pharmacology

Acts as a proton acceptor, which combines with hydrogen ions, liberating bicarbonate buffer, to correct acidosis. It buffers both metabolic and respiratory acids, limiting carbon dioxide generation. Also an osmotic diuretic.

Absorption

30% of dose is not ionized

Distribution

Distributes quickly into extracellular space; at steady state distributes into a volume slightly greater than total body water; penetrates slowly intracellularly

Excretion

Urine (>75%) within 8 hours

Half-Life Elimination

5.6 hours

Use: Labeled Indications

Correction of metabolic acidosis associated with cardiac bypass surgery or cardiac arrest; to correct excess acidity of stored blood that is preserved with acid citrate dextrose (ACD); indicated in infants needing alkalinization after receiving maximum sodium bicarbonate (8-10 mEq/kg/24 hours)

Contraindications

Hypersensitivity to tromethamine or any component of the formulation; uremia or anuria; chronic respiratory acidosis (neonates); salicylate intoxication (neonates)

Dosing: Adult

Dose depends on buffer base deficit; when deficit is known: tromethamine (mL of 0.3 M solution) = body weight (kg) x base deficit (mEq/L) x 1.1

Metabolic acidosis with cardiac arrest:

IV: 3.6-10.8 g (111-333 mL); additional amounts may be required to control acidosis after arrest reversed

Open chest: Intraventricular: 2-6 g (62-185 mL). Note: Do not inject into cardiac muscle

Acidosis associated with cardiac bypass surgery: IV: Average dose: 9 mL/kg (2.7 mEq/kg); 500 mL is adequate for most adults; maximum dose: 500 mg/kg over at least 1 hour

Excess acidity of acid citrate dextrose (ACD) blood in cardiac bypass surgery: 15-77 mL of 0.3 molar solution added to each 500 mL of ACD blood

Dosing: Geriatric

Refer to adult dosing.

Dosing: Renal Impairment

No dosage adjustment provided in manufacturer’s labeling. Tromethamine is substantially excreted by the kidneys; use with caution; monitor ECG and potassium levels.

Dosing: Hepatic Impairment

No dosage adjustment provided in manufacturer’s labeling.

Administration

Correction of metabolic acidosis in cardiac bypass surgery: Administer by slow IV infusion over at least 1 hour (maximum rate: 500 mg/kg over at least 1 hour); rapid administration may result in prolonged hypoglycemia.

Correction of ACD blood acidity in cardiac bypass surgery: Add to each 500 mL of ACD blood used to prime the pump-oxygenator.

Correction of metabolic acidosis in cardiac arrest: If chest is open, instill directly into ventricular cavity; do NOT inject into cardiac muscle. If chest is not open, inject into a large peripheral vein.

Vesicant (with IV administration); ensure proper needle or catheter placement prior to and during administration; avoid extravasation.

Extravasation management: If extravasation occurs, stop IV administration immediately and disconnect (leave cannula/needle in place); gently aspirate extravasated solution (do NOT flush the line); remove needle/cannula; elevate extremity.

Storage

Store at 20°C to 25°C (68°F to 77°F). Protect from freezing.

Drug Interactions

Alpha-/Beta-Agonists (Indirect-Acting): Alkalinizing Agents may increase the serum concentration of Alpha-/Beta-Agonists (Indirect-Acting). Monitor therapy

Amphetamines: Alkalinizing Agents may decrease the excretion of Amphetamines. Consider therapy modification

Flecainide: Tromethamine may increase the serum concentration of Flecainide. Monitor therapy

Mecamylamine: Alkalinizing Agents may increase the serum concentration of Mecamylamine. Monitor therapy

Memantine: Alkalinizing Agents may increase the serum concentration of Memantine. Monitor therapy

QuiNINE: Alkalinizing Agents may increase the serum concentration of QuiNINE. Monitor therapy

Adverse Reactions

Frequency not defined.

Cardiovascular: Hypervolemia, venospasm

Endocrine & metabolic: Hyperkalemia, hypoglycemia (usually doses >500 mg/kg administered over <1 hour)

Hepatic: Hepatic necrosis (resulted during delivery via umbilical venous catheter)

Local: Necrosis with extravasation, phlebitis, tissue irritation

Respiratory: Apnea, pulmonary edema, respiratory depression

Warnings/Precautions

Concerns related to adverse effects:

• Extravasation: Vesicant; ensure proper needle or catheter placement prior to and during administration; avoid extravasation. May cause tissue inflammation and necrosis.

• Hypoglycemia: May cause hypoglycemia with extremely large doses.

• Respiratory depression: May cause respiratory depression; monitor closely especially if patient not intubated.

Disease-related concerns:

• Renal impairment: Use with caution in patients with renal impairment; reduce dose and monitor pH carefully.

Other warnings/precautions:

• Duration of therapy: Drug should not be given for a period of longer than 24 hours unless for a life-threatening situation.

Monitoring Parameters

Serum electrolytes (especially potassium, blood glucose); renal function, arterial blood gases, ECG monitoring, fluid status, ventilation rate

Check infusion site frequently during administration.

Pregnancy Risk Factor

C

Pregnancy Considerations

Animal studies have not been conducted. There are no adequate and well-controlled studies in pregnant women. Use only if potential benefit outweighs possible risk to the fetus.

Patient Education

• Discuss specific use of drug and side effects with patient as it relates to treatment. (HCAHPS: During this hospital stay, were you given any medicine that you had not taken before? Before giving you any new medicine, how often did hospital staff tell you what the medicine was for? How often did hospital staff describe possible side effects in a way you could understand?)

• Have patient report immediately to prescriber severe skin irritation or significant injection site pain or irritation (HCAHPS).

• Educate patient about signs of a significant reaction (eg, wheezing; chest tightness; fever; itching; bad cough; blue skin color; seizures; or swelling of face, lips, tongue, or throat). Note: This is not a comprehensive list of all side effects. Patient should consult prescriber for additional questions.

Intended Use and Disclaimer: Should not be printed and given to patients. This information is intended to serve as a concise initial reference for healthcare professionals to use when discussing medications with a patient. You must ultimately rely on your own discretion, experience and judgment in diagnosing, treating and advising patients.

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