Usual Adult Dose for Beriberi:
10 to 20 mg IM three times daily for up to 2 weeks. Thereafter, use an oral therapeutic multivitamin preparation containing 5 to 10 mg thiamine daily for one month. A complete and balanced diet should follow. Neuritis of pregnancy:If vomiting severe to preclude oral therapy, give 5 to 10 mg IM daily.'Wet' with myocardial failure:Treat as an emergency cardiac condition. Thiamine is administered slowly by the IV route.
Usual Adult Dose for Thiamine Deficiency:
If dextrose administered: to patients with marginal thiamine status, give 100 mg in each of the first few liters of IV fluid to avoid precipitating heart failure.
Usual Adult Dose for Vitamin/Mineral Supplementation:
50 to 100 mg orally once a day
Usual Adult Dose for Wernicke's Encephalopathy:
100 mg IV as an initial dose followed by 50 to 100 mg/day IM or IV until the patient is on a regular, balanced, diet.
Usual Pediatric Dose for Beriberi:
10 to 25 mg IM or IV daily (if critically ill), or 10 to 50 mg orally every day for 2 weeks, then 5 to 10 mg orally daily for 1 month.  If collapse occurs: 25 mg IV.  Administer with caution.
Usual Pediatric Dose for Thiamine Deficiency:
If dextrose administered: to patients with marginal thiamine status, give 100 mg in each of the first few liters of IV fluid to avoid precipitating heart failure.
Usual Pediatric Dose for Vitamin/Mineral Supplementation:
Infants: 0.3 to 0.5 mg orally once a day; children: 0.5 to 1 mg orally once a day.
 Detailed Thiamine dosage information
