Drug reference

Thiamine

Water-soluble vitamin (B1) · Nutritional Supplement

Also known as Thiamine Hydrochloride, Vitamin B1

START

Wernicke: 500 mg IV TID × 2–3 days; at-risk prophylaxis 200–300 mg/day; give BEFORE glucose

TYPICAL MAX

No toxic ceiling; acute Wernicke up to ~1500 mg/day IV divided

STOP IF

Anaphylactoid reaction to parenteral thiamine

WATCH

Give thiamine before/with IV glucose in at-risk patients; clinical Wernicke triad response; observe IV doses

CDSCO approvedOTC (for oral preparations); Schedule H (for parenteral preparations)Jan AushadhiATC A11DA01

Dose laddermg/d

Renal dose adjustmenteGFR mL/min/1.73m²

KDIGO 2024 + manufacturer label

Pharmacokineticsplasma · t hours

ONSET: 1h · absorption/repletion begins
PEAK: 1.5h · oral Cmax (~immediate IV)
t½: 1.8h · plasma t½
DURATION: 1d · daily dosing interval

EXCRETION

Renal; excess excreted unchanged

route + CYP

INTERACTIONS

1 major

SEVERE in our sources

PREGNANCY

Safe and recommended — requirement increases in pregnancy; treat deficiency promptly (e.g. hyperemesis)

FDA category + note

Top interactionssee all 5 →

GlucoseSevereDatabaseKimi deep-research + Cla

Available in India

42 branded formulations and 20 fixed-dose combinations. Look up specific brands in the Drugs workspace.

Jan Aushadhi — generic available at GoI pharmacies

Mechanism

Thiamine is converted to thiamine pyrophosphate (TPP), an essential cofactor for pyruvate dehydrogenase, alpha-ketoglutarate dehydrogenase and transketolase — enzymes central to oxidative decarboxylation and the pentose-phosphate pathway. Deficiency impairs ATP generation in highly oxidative tissues (brain, myocardium, peripheral nerve), causing Wernicke encephalopathy, beriberi and lactic acidosis.

Indications

Wernicke encephalopathy / Wernicke–Korsakoff syndrome (treatment and prophylaxis)Thiamine-deficiency states (alcohol use disorder, malnutrition, hyperemesis, post-bariatric, refeeding)Wet and dry beriberiAdjunct in unexplained lactic acidosis

Dosing

Adult: Wernicke treatment: 500 mg IV three times daily for 2–3 days, then 250 mg IV/IM daily for 3–5 days. At-risk prophylaxis: 200–300 mg/day. Nutritional deficiency: 25–100 mg PO daily.
Pediatric: Beriberi: 10–25 mg IV/IM daily or 10–50 mg PO daily; infantile beriberi may need higher acute IV doses.
Renal adjustment: No adjustment (water-soluble; excess renally cleared).
Hepatic adjustment: No adjustment.
Geriatric: No specific adjustment.
Max dose: No defined toxic ceiling; high-dose regimens up to ~1500 mg/day IV in divided doses used acutely for Wernicke

Pharmacokinetics

Onset

Biochemical repletion within hours; clinical Wernicke improvement hours–days

Peak effect

IV immediate; oral ~1–2 h

Duration

Depends on stores/intake

Half-life

~1.8 h (biphasic); body stores limited (~30 mg, ~18-day reserve)

Bioavailability

Oral absorption saturable (~5 mg per dose actively absorbed); IV/IM 100%

Protein binding

Largely albumin-bound in plasma

Metabolism

Hepatic to multiple metabolites; converted to active TPP intracellularly

Excretion

Renal — unchanged drug and metabolites; excess excreted readily

Contraindications

Known hypersensitivity to thiamine (rare; anaphylaxis reported with IV)

Side effects

Common

Generally very well toleratedTransient injection-site warmth/discomfort (parenteral)

Serious

Anaphylaxis/anaphylactoid reaction (rare, almost exclusively IV — give slowly, have resuscitation available)

Pregnancy & lactation

Pregnancy

Safe and recommended — requirement increases in pregnancy; treat deficiency promptly (e.g. hyperemesis)

Lactation

Compatible — normal component of breast milk; supplement deficient mothers

Drug interactions

Glucose

Severe

Database

Carbohydrate load without thiamine precipitates/worsens Wernicke encephalopathy in deficient patients

Give thiamine before or with IV glucose in at-risk patients