|THIAMINE HYDROCHLORIDE (VITAMIN B1)
Classifications: vitamin b1; Therapeutic: vitamin b1 replacement therapy
Pregnancy Category: A, C if dose is above RDA
50 mg, 100 mg, 250 mg tablets; 20 mg enteric-coated tablet; 100 mg/mL injection
Water-soluble B1 vitamin and member of B-complex group used for thiamine replacement therapy. Functions as an essential coenzyme in carbohydrate
metabolism and has a role in conversion of tryptophan to nicotinamide.
Effectiveness is evidenced by improvement of clinical manifestations of thiamine deficiency: Anorexia, gastric distress,
depression, irritability, insomnia, palpitations, tachycardia, loss of memory, paresthesias, muscle weakness and pain, elevated
blood pyruvic acid level (diagnostic test for thiamine deficiency), and elevated lactic acid level.
Treatment and prophylaxis of beriberi, to correct anorexia due to thiamine deficiency states, and in treatment of neuritis
associated with pregnancy, pellagra, and alcoholism, including Wernicke-Korsakoff syndrome. Therapy generally includes other
members of vitamin b complex, since thiamine deficiency rarely occurs alone. Severe deficiency is characterized by ophthalmoplegia,
polyneuropathy, muscle wasting ("dry" beriberi), edema, serous effusions, and CHF ("wet" beriberi).
Pregnancy (category C if dose is above RDA).
Pregnancy (category A).
Route & Dosage
Adult: IV/IM 50100 mg t.i.d., then 510 mg PO for 1 mo
Child: IV/IM 1025 mg t.i.d. then, 510 mg PO for 1 mo
Adult: IV/IM 100 mg/d until PO 50100 mg/d as tolerated
Adult: IV/IM 100 mg/d then 50100 mg/d until on normal diet
Adult: PO 1530 mg/d
Child: PO 1050 mg/d
- Do not crush or chew enteric-coated tablets. These must be swallowed whole.
- Give deep IM into a large muscle; may be painful. Rotate sites and apply cold compresses to area if necessary for relief
- Note: Intradermal test dose is recommended prior to administration in suspected thiamine sensitivity. Deaths have occurred following
PREPARE: Direct: Give undiluted. IV Infusion: Diluted in 1000 mL of most IV solutions.
ADMINISTER: Direct: Give at a rate of 100 mg over 5 min. IV Infusion: Give at the ordered rate.
INCOMPATIBILITIES Solution/additive: Amobarbital, diazepam, furosemide, phenobarbital.
- Preserve in tight, light-resistant, nonmetallic containers. Thiamine is unstable in alkaline solutions (e.g., solutions
of acetates, barbiturates, bicarbonates, carbonates, citrates) and neutral solutions.
Adverse Effects (≥1%)Body as a Whole:
Feeling of warmth, weakness, sweating, restlessness, tightness of throat, angioneurotic edema, anaphylaxis. Respiratory:
edema. CV: Cardiovascular collapse,
slight fall in BP following rapid IV administration
GI hemorrhage, nausea. Skin:
No clinically significant interactions established.
Limited from GI tract. Distribution:
Widely distributed, including into breast milk. Elimination:
Assessment & Drug Effects
- Record patient's dietary history carefully as an essential part of vitamin replacement therapy. Collaborate with physician,
dietitian, patient, and responsible family member in developing a diet teaching plan that can be sustained by patient.
- Note: Body requirement of thiamine is directly proportional to carbohydrate intake and metabolic rate; requirement increases when
diet consists predominantly of carbohydrates. Total absence of dietary thiamine produce deficiency state in about 3 wk.
Patient & Family Education
- Fooddrug relationships: Learn about rich dietary sources of thiamine (e.g., yeast, pork, beef, liver, wheat and other
whole grains, nutrient-added breakfast cereals, fresh vegetables, especially peas and dried beans).