Thiamine Injection - Administration Guide

Indications for Parenteral Thiamine

• Wernicke's encephalopathy (most urgent)
• Alcohol withdrawal / Wernicke-Korsakoff syndrome prevention
• Beriberi (wet or dry)
• Severe malnutrition, refeeding syndrome
• Hyperemesis gravidarum (pregnancy vomiting)
• Any patient receiving IV glucose who may be thiamine-deficient

Routes of Administration

Doses by Indication

• Standard: 100 mg IV initial dose, then 50-100 mg IM/IV daily until regular diet resumed
• High-dose (RCP/European guideline): 500 mg IV three times daily x 3 days, then if responding: 250 mg IM/IV once daily x 5 days

• Dry (peripheral neuropathy): 10-25 mg/day IM or slow IV x 2 weeks
• Wet (cardiac failure): Must give IV slowly - treat as emergency; 100-500 mg IV may be needed

• 100 mg IM or IV, then 100 mg orally/IM/IV for up to 5 days

• 5-10 mg IM daily

Step-by-Step: IV Injection

1. Check the solution - should be clear and colourless; discard if cloudy or contains particles
2. Dilute for infusion: Mix in 50-100 mL normal saline (0.9% NaCl)
3. Rate: Infuse over at least 30 minutes (minimum 10 minutes for slow direct IV push)
4. Never give as rapid IV bolus - risk of anaphylaxis and cardiovascular collapse
5. Have resuscitation equipment ready (anaphylaxis can occur with any parenteral dose)
6. Give before glucose - always administer thiamine BEFORE any dextrose/glucose infusion in at-risk patients; glucose loading can precipitate or worsen Wernicke's by consuming the last thiamine reserves

Step-by-Step: IM Injection

1. Site: Deltoid or gluteal (vastus lateralis in infants)
2. Draw up the required dose; inspect solution
3. Clean skin with alcohol swab; allow to dry
4. Insert needle at 90 degrees; aspirate to confirm not in vessel
5. Inject slowly; withdraw needle; apply light pressure
6. Single-use only - discard any remaining solution after use
7. Monitor for local reaction

Critical Safety Points

• Anaphylaxis risk: Parenteral thiamine can rarely cause anaphylactic reactions. Always have adrenaline (epinephrine), antihistamines, and resuscitation equipment available before giving any injection.
• Skin test: If the patient has a history of allergic reaction to a previous thiamine injection, give a diluted intradermal test dose first.
• Glucose before thiamine = dangerous: In any thiamine-deficient patient (alcoholic, malnourished), giving IV glucose FIRST can precipitate acute Wernicke's encephalopathy. Thiamine always comes first.
• IM preferred over IV when urgency allows - lower anaphylaxis risk than rapid IV
• Repeated IM injections: Can cause local reactions; rotate sites
• Oral route is equally effective as parenteral for non-acute alcoholics after 5 days of parenteral loading

Available Formulations

• 100 mg/mL solution (most common - 1 mL or 2 mL vials)
• 50 mg/mL solution