Thiamine

BRAND NAMES:

Fortaplex: It contains the active ingredient of thiamine. It is available in the form of an oral solution used to treat vitamin deficiency.

Infuvite pediatric: It contains the active ingredients of thiamine. It is available in the form of an intravenous infusion used for multiple vitamin supplements.

MECHANISM OF ACTION:

Water-soluble vitamin B1 is a component of the B complex. Co-carboxylase, sometimes referred to as thiamine pyrophosphate, is a co-enzyme that is created when vitamin B1 combines with adenosine triphosphate. Its function in the metabolism of carbohydrates is to decarboxylate pyruvic acid and alpha-ketoacids into CO2 and acetaldehyde. Elevated blood pyruvic acid levels indicate a deficiency of vitamin B1.

PHARMACOKINETICS:

Absorption: The intestinal enzyme phosphate hydrolyses thiamine into its free form, which is then absorbed by the small intestine. Thiamine is actively absorbed and passively diffused by the small intestine at nutritional and pharmacological doses, respectively. It has a short half-life of 14 to 18 days; therefore, regular dietary intake of thiamine is necessary.

Distribution: Thiamine gets distributed to various organs. Limited quantities of thiamine are stored in the liver, heart, kidney, and brain for a short duration.

Metabolism: Thiamine gets metabolized through phosphorylation. In the human body, thiamine exists mainly as thiamine diphosphate, also known as TPP. TPP is the metabolic form of thiamine and serves as a cofactor for various enzymes during the metabolism of glucose, lipids, and proteins.

Excretion: Thiamine is a water-soluble vitamin; excess thiamine is excreted in the urine.

PHARMACODYNAMICS:

Thiamine helps the body's cells transform carbohydrates into energy. Carbohydrates' principal job is to provide energy to the body, specifically the brain and neurological system. It also promotes muscular contraction and nerve transmission.

DOSAGE AND ADMINISTRATION:

• Oral thiamine is available as a pill, capsule, and solution. It is taken as prescribed by the doctor once a day. 
• There are three different strengths of pills available: 50 mg, 100 mg, and 250 mg. 
• 50 mg strength capsules are one form in which it comes. 
• Additionally, an injectable solution with a 100 mg/mL strength is offered. 

DRUG INTERACTIONS:

Drug interactions with thiamine may include

Macrolides: decrease the thiamine levels among the patients taking erythromycin. This is due to the inhibition of thiamine transport mediated by the protein.

Loop diuretics: patients treated with a high dose of furosemide for a prolonged period are predisposed to thiamine deficiency. It increases the excretion of thiamine and can disrupt the absorption of thiamine in the kidneys.

Patiromer: patiromer can reduce the absorption of orally administered thiamine.  

CONTRAINDICATIONS:

Thiamine's contraindications included intolerance to vitamin B1 or any component of a vitamin B1-containing product.

SIDE EFFECTS:

Side effects of thiamine may cause

• Hives
• Flushing
• Itching
• Restlessness
• Sweating
• Nausea

OVERDOSE:

Symptoms of overdose may include

• Stomach upset
• Weakness
• Headache
• Convulsions
• Vasodilation
• Cardiac dysrhythmias
• Hypotension

TOXICITY:

Thiamine toxicity is uncommon as excess is readily excreted although long-term supplementation of amounts larger than 3 grams has been known to cause toxicity.