Vitamin B1 (Thiamine)

Category:

• Vitamin

Description:

• Dietary supplement; water-soluble vitamin

Indications:

• Vitamin B₁deficiency due to anorexia, nausea, vomiting, severe alcoholism

• Impaired GI absorption in malabsorption syndromes

• Beriberi

• Unlabeled uses: mosquito repellant (?)

Contraindications:

  Precautions:

• Pregnancy category A

• Vitamin B₁ deficiency is characterized by:

  • Weakness

  • Paresthesia

  • Hypotension

• Patients with thiamine-deficiency may experience a sudden onset or worsening of Wernicke’s encephalopathy, characterized by:

  • Horizontal nystagmus

  • Bilateral sixth nerve palsy

  • Ataxia

  • Confusion

• Wernicke’s encephalopathy may occur in:

  • Excessive alcoholism

  • Prolonged IV feeding

  • Hyperemesis gravidarum

  • Anorexia nervosa

  • Prolonged fasting

  • Refeeding after starvation.

  Adverse Reactions (Side Effects):

• Relatively non-toxic in therapeutic doses

• Sensitivity reactions may occur with excessive IV dosing.

• Pruritis, urticaria, warmth sensation, weakness, sweating

Dosage:

• Dietary sources: rice, grains, pork, beef, fresh peas and beans

• Administered orally (tablets) or injection

• Dietary supplementation (RDA: recommended daily allowance):

  • Adult males: 1.5mg per day

  • Adults females: 1.1mg per day

• Beriberi: 10-20mg IM tid for 2 weeks, followed by 5-10mg oral thiamine daily for one month to saturate

• Wet beriberi with myocardial failure: 10-30mg IV tid