thiamine

thye-a-min

Betaxin, Bewon, Biamine, vitamin B1

Classification
Therapeutic: Pharmacologic:

Copyright © 2009 by F.A. Davis Company

Indications

Treatment of thiamine deficiencies (beriberi)
Prevention of Wernicke’s encephalopathy
Dietary supplement in patients with GI disease, alcoholism, or cirrhosis
Required for carbohydrate metabolism
Therapeutic Effects: Replacement in deficiency states

Pharmokinetics

Absorption: Well absorbed from the GI tract by an active process. Excessive amounts are not absorbed completely. Also well absorbed from IM sites
Distribution: Widely distributed. Enters breast milk
Metabolism and Excretion: Metabolized by the liver. Excess amounts are excreted unchanged by the kidneys
Half-life: Unknown

TIME/ACTION PROFILE time for symptoms of deficiency—edema and heart failure—to resolve†
ROUTE ONSET PEAK DURATION
PO, IM, IV hrdaysdays–wks
†Confusion and psychosis take longer to respond

Contraindications/Precautions

Contraindicated in: Hypersensitivity
Known alcohol intolerance or bisulfite hypersensitivity (elixir only)
Use Cautiously in: Wernicke’s encephalopathy (condition may be worsened unless thiamine is administered before glucose)

Adverse Reactions/Side Effects*

Adverse reactions and side effects are extremely rare and are usually associated with IV administration or extremely large dosesCNS: restlessness, weakness. EENT: tightness of the throat. pulmonary edema, respiratory distressvascular collapse, hypotension, vasodilationGI: GI bleeding, nausea. Derm: cyanosis, pruritus, sweating, tingling, urticaria, warmth. Misc: angioedema.

Interactions

Drug–Drug: None significant

Route/Dosage

Thiamine Deficiency (Beriberi)PO (Adults): 5–10 mg 3 times daily
10–50 mg/day in divided doses
5–100 mg 3 times daily
10–25 mg/day
Dietary SupplementPO (Adults): 1–1.6 mg/day
4–10 yr0.9–1 mg/day
birth–3 yr0.3–0.7 mg/day

Availability (generic available)

Tablets: 5 mg&OTC;, 10 mg&OTC;, 25 mg&OTC;, 50 mg&OTC;, 100 mg&OTC;, 250 mg&OTC;, 500 mg&OTC;
Elixir250 mcg/5 ml&OTC;
Injection: 100 mg/ml in 1-ml ampules and prefilled syringes and 1-, 2-, 10-, and 30-ml vials
other vitamins, minerals, and trace elements in multi-vitamin preparations&OTC;

NURSING IMPLICATIONS

Assessment
  • Assess patient for signs and symptoms of thiamine deficiency (anorexia, GI distress, irritability, palpitations, tachycardia, edema, paresthesia, muscle weakness and pain, depression, memory loss, confusion, psychosis, visual disturbances, elevated serum pyruvic acid levels)
    Assess patient’s nutritional status (diet, weight) prior to and throughout therapy
    Monitor patients receiving IV thiamine for anaphylaxis (wheezing, urticaria, edema)
  • Lab Test Considerations: May interfere with certain methods of testing serum theophylline, uric acid, and urobilinogen concentrations.
Potential Nursing Diagnoses Implementation
  • Because of infrequency of single B-vitamin deficiencies, combinations are commonly administered
    Parenteral administration is reserved for patients in whom oral administration is not feasible
    Administration may cause tenderness and induration at injection site. Cool compresses may decrease discomfort
    Sensitivity reactions and death have occurred from IV administration. An intradermal test dose is recommended in patients with suspected sensitivity. Monitor site for erythema and induration
    Administer undiluted at 100 mg/ml
    Administer at a rate of 100 mg over 5 min
    May be diluted in dextrose/Ringer’s or LR combinations, dextrose/saline combinations, D5W, D10W, Ringer’s and LR injection, 0.9% NaCl, or 0.45% NaCl and is usually administered with other vitamins
    famotidine Solutions with neutral or alkaline pH, such as carbonates, bicarbonates, citrates, and acetates.
Patient/Family Teaching
  • Encourage patient to comply with dietary recommendations of health care professional. Explain that the best source of vitamins is a well-balanced diet with foods from the four basic food groups
    Teach patient that foods high in thiamine include cereals (whole grain and enriched), meats (especially pork), and fresh vegetables; loss is variable during cooking
    Caution patients self-medicating with vitamin supplements not to exceed RDA (see ). The effectiveness of megadoses of vitamins for treatment of various medical conditions is unproved and may cause side effects.
Evaluation/Desired Outcomes
  • Prevention of or decrease in the signs and symptoms of vitamin B deficiency.
  • Decrease in the symptoms of neuritis, ocular signs, ataxia, edema, and heart failure may be seen within hours of administration and may disappear within a few daysConfusion and psychosis may take longer to respond and may persist if nerve damage has occurred