Thiamine HCl (B₁)

A to Z Drug Facts

(THIGH-uh-min HIGH-droe-KLOR-ide)

Thiamilate,  Betaxin

Class: Vitamin

 Action Thiamine, after conversion to thiamine pyrophosphate, functions with adenosine triphosphate (ATP) in carbohydrate metabolism. Deficiencies result in beriberi, characterized by GI manifestations, peripheral neuropathy and cerebral deficits.

 Indications Prophylaxis or treatment of thiamine deficiency (beriberi). Parenteral use indicated when oral therapy not feasible or advisable. Unlabeled use(s): Mosquito repellant; treatment of ulcerative colitis, chronic diarrhea, cerebellar syndrome, polyneuritis; appetite stimulant; prevention of Wernicke-Korsakoff syndrome.

 Contraindications Standard considerations.

 Route/Dosage

ADULTS: PO 0.5 mg/1000 kcal intake. RDA is 1.2–1.5 mg (adult males), 1 to 1.1 mg (adult females) 1.2 mg (CHILDREN 6–10 YR), 0.8–1 mg (CHILDREN < 6 YR), and 0.3–0.5 mg (infants).

Wet Beriberi with Myocardial Failure

ADULTS: IV 10–30 mg tid. Treat as emergency cardiac condition.

Beriberi

ADULTS: IM 10–20 mg tid for 2 wk, then PO 5–10 mg (as part of multivitamin) for 1 mo. CHILDREN: IV 10 mg initially followed by IM 10 mg bid for 3 days, then 10 mg daily for 6 wk.

Thiamine Deficiency Secondary to Alcoholism (Wernicke's Encephalopathy)

ADULTS: IV 50–100 mg; then IM/IV 50–100 mg/day until consuming normal diet; then PO 40 mg/day.

Metabolic Disorders

ADULTS: PO 10–20 mg daily; maximum doses of 4 g daily have been used.

 Interactions

IV incompatibilities: Unstable in neutral or alkaline solutions. Incompatible with sulfite containing solutions. Incompatible with barbiturates, erythromycin, lactobionate, citrates.

 Lab Test Interferences None well documented.

 Adverse Reactions

CV: Cardiovascular collapse; hypotension; death. CNS: Weakness; restlessness. DERM: Pruritus; urticaria. EENT: Tightness of throat. GI: Nausea; hemorrhage into GI tract. RESP: Pulmonary edema; cyanosis. OTHER: Feeling of warmth; sweating; anaphylaxis; angioneurotic edema; local tenderness and induration (after IM use).

 Precautions

Pregnancy: Category A. (Category C if used in doses greater than the RDA.) Lactation: Undetermined. Hypersensitivity: Can occur. Deaths have resulted from IV administration. Intradermal test dose is recommended if sensitivity is suspected. Deficiency: Single vitamin B₁ deficiency is rare; suspect multiple vitamin deficiencies. Wernicke's encephalopathy: May occur or worsen suddenly in thiamine-deficient patients given glucose. If deficiency is suspected, give thiamine before or with dextrose-containing fluids.

 Administration/Storage

• As a nutritional supplement, calculate dosage based on standard dose of 0.5 mg/1000 kcal daily intake.
• For IV infusion, give at rate of £ 100 mg/³ 5 min.
• For IM injection, rotate injection sites if pain and inflammation occur. Administer via Z-track method to minimize pain. Application of cold may decrease pain.
• Store in light-resistant container.

 Assessment/Interventions

• Obtain patient history, including drug history and any known allergies.
• Give intradermal test dose first if hypersensitivity is suspected.
• Assess the patient for other nutritional deficiencies, since single vitamin deficiencies are rare.
• Administer thiamine before giving IV solutions containing glucose as glucose administration may cause sudden worsening of Wernicke's encephalopathy.
• Monitor for adverse reactions and notify physician of signs of weakness, restlessness, cardiovascular collapse, pulmonary edema, throat tightness, nausea, gastrointestinal hemorrhage, pruritus, urticaria, feeling of warmth, diaphoresis, cyanosis, angioneurotic edema.

 Patient/Family Education

• Alert patient to potential lab test abnormalities.
• Inform patient of all potential adverse reactions and of importance of reporting problems to physician.
• Teach patient about proper nutritional balance needed in diet. Thiamine-rich foods are yeast, beef, liver, legumes, beans and whole grains.

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Copyright © 2003 Facts and Comparisons
David S. Tatro
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