thiamine (vitamin b1)

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thiamine (vitamin b1)


Vitamin B1 (Thiamine) Supplements

Oral Administration

Thiamine, vitamin B1 may be administered without regard to meals.

Injectable Administration

Administer intramuscularly or intravenously. Parenteral therapy is usually reserved for patients for which oral thiamine is not feasible.
Prior to intravenous administration, an intradermal test dose should be administered to patients in whom a sensitivity might be suspected.
Visually inspect parenteral products for particulate matter and discoloration prior to administration whenever solution and container permit.

Intravenous Administration

Direct IV injection:
No dilution is necessary.
Inject each 100 mg thiamine, vitamin B1 via slow IV push.
Continuous IV infusion:
Dilute thiamine, vitamin B1 in a compatible infusion solution.
Administer at a rate prescribed by the physician.

Intramuscular Administration

Inject thiamine, vitamin B1 deeply into a large muscle.
Tenderness and induration may occur at the injection site. Discomfort may be reduced by applying cool compresses.

Adverse Reactions

angioedema / Rapid / Incidence not known
anaphylactoid reactions / Rapid / Incidence not known
pulmonary edema / Early / Incidence not known
GI bleeding / Delayed / Incidence not known
cyanosis / Early / Incidence not known


pruritus / Rapid / 1.0-1.0
restlessness / Early / Incidence not known
diaphoresis / Early / Incidence not known
sneezing / Early / Incidence not known
urticaria / Rapid / Incidence not known
nausea / Early / Incidence not known
weakness / Early / Incidence not known
injection site reaction / Rapid / Incidence not known

Dea Class



Water-soluble vitamin; found in yeast, cereal grains, legumes, peas, nuts, pork, and beef; deficiency causes beriberi; considered a standard agent in the treatment of a patient with undiagnosed coma and to prevent Wernicke/Korsakoff syndrome.

Dosing Considerations
Hepatic Impairment

It appears that no dosage adjustments are needed.

Renal Impairment

It appears that no dosage adjustments are needed.
Intermittent hemodialysis
Patients on dialysis may have increased needs for thiamine.
Peritoneal dialysis
Patients on dialysis may have increased needs for thiamine.

Drug Interactions

Patiromer: (Moderate) Separate the administration of patiromer and oral thiamine by at least 3 hours if concomitant use is necessary. Simultaneous oral coadministration may reduce gastrointestinal absorption of thiamine and reduce its efficacy. Patiromer has been observed to bind some oral medications when given at the same time and separating administration by at least 3 hours has effectively mitigated this risk.

How Supplied

Thiamine (Vitamin B1)/Thiamine Hydrochloride (Vitamin B1) Intramuscular Inj Sol: 1mL, 100mg
Thiamine (Vitamin B1)/Thiamine Hydrochloride (Vitamin B1) Intravenous Inj Sol: 1mL, 100mg

Maximum Dosage

Upper tolerable intake levels in healthy, non-vitamin deficient individuals are not determinable due to a lack of data.

Mechanism Of Action

Mechanism of Action: Thiamine combines with adenosine triphosphate (ATP) in the liver, kidneys, and leukocytes to produce thiamine diphosphate. Thiamine diphosphate acts as a coenzyme in carbohydrate metabolism, in transketolation reactions, and in the utilization of hexose in the hexose-monophosphate shunt. Without adequate thiamine, pyruvic acid does not undergo conversion to acetyl-CoA and cannot enter the Krebs cycle. Pyruvic acid accumulates in the blood and is subsequently converted to lactic acid, with the potential development of lactic acidosis. Diminished production of NADH in the Krebs cycle also results in lactic acid production through facilitation of anaerobic glycolysis.Thiamine deficiency appears as a nonspecific syndrome: headache, nausea, malaise, myalgias. Severe thiamine deficiency causes beriberi. Beriberi can affect the cardiovascular system (wet beriberi) and the nervous system (dry beriberi and the Wernicke-Korsakoff syndrome). Cardiovascular manifestations include peripheral vasodilation, biventricular failure, and edema. Neurologic symptoms include neuropathy, ataxia, retrograde amnesia, impaired ability to learn, and confabulation. Once Korsakoff's syndrome appears, thiamine supplementation is successful in only half of the patients.


Thiamine is administered orally and by intramuscular or intravenous injection.  Thiamine is widely distributed. Body storage of thiamine is limited to about 30 mg. Thiamine is distributed into breast milk at a rate of about 100—200 mcg daily from normal dietary intake. There is little excretion of thiamine or its metabolites at physiologic doses. Following large doses, saturation occurs, with subsequent renal excretion as pyrimidine.

Oral Route

Small oral doses are readily absorbed from the GI tract, but absorption of large doses is limited. Administration with food reduces the rate of absorption.

Intramuscular Route

Following IM administration of thiamine, vitamin B1, absorption is rapid and complete.

Pregnancy And Lactation

Thiamine is classified as FDA pregnancy risk category A. Appropriate maternal thiamine (vitamin B1) intake is encouraged during pregnancy, and no maternal or fetal complications associated with maternal dietary intake or supplementation to achieve adequate intake goals have been reported. As with other water-soluble vitamins, the pregnancy risk factor increases to FDA risk category C if the vitamin is used in dosages exceeding the Recommended Dietary Allowance (RDA) during pregnancy.

According to the manufacturer, caution should be exercised when thiamine is administered during breast-feeding. However, while thiamine is excreted in human milk, appropriate maternal intake of thiamine (vitamin B1) is important during lactation, and no maternal or fetal complications have been identified with maternal supplementation to achieve adequate intake goals during breast-feeding. Seizures have occurred in nursing infants of mothers with thiamine deficiency, although causality has not been established. Supplementation with thiamine is recommended in lactating women whose diets do not provide adequate amounts of thiamine. The American Academy of Pediatrics classifies thiamine as compatible with breast-feeding. Consider the benefits of breast-feeding, the risk of potential infant drug exposure, and the risk of an untreated or inadequately treated condition. If a breast-feeding infant experiences an adverse effect related to a maternally administered drug, healthcare providers are encouraged to report the adverse effect to the FDA.