Pabrinex Ivhp (Intravenous High Potency)

Wernicke’s encephalopathy can be difficult to diagnose, and the consequences of leaving it untreated can be devastating. Pabrinex is a combination of water-soluble vitamins B and C, which is used parenterally to rapidly treat severe depletion or malabsorption, particularly after alcoholism.As thiamine does not exist as a licensed parenteral product, Pabrinex is widely used to treat and prevent Wernicke’s encephalopathy. An alternative approach is to use an unlicensed IV thiamine product. Pabrinex IVHP is supplied in two ampoules which contain:

Ampoule no. 1 (5 ml)
Thiamine hydrochloride (Vit B1) 250mg
Riboflavin (Vit B2) 4mg
Pyridoxine hydrochloride (Vit B6) 50mg

Ampoule no. 2 (5 ml)
Ascorbic acid (Vit C) 500mg
Nicotinamide (Vit B3) 160mg
Anhydrous glucose 1000mg

Note: a double-strength ampoule pair exists of 10 ml. All doses mentioned here refer to the 5 ml product.

Uses
Treatment and prevention of Wernicke’s encephalopathy

At-risk groups:
                      Alcohol misusers
                      Eating disorders
                      Long-term parenteral nutrition
                      Hyperemesis gravidarum
                      Dialysis

Administration
To prepare Pabrinex IVHP: draw up contents of both ampoules numbers 1 and 2 into one syringe and mix. Add this to 50–100 ml of sodium chloride 0.9% and administer over 30 min
Pabrinex should be administered before parenteral glucose is given, as in thiamine deficiency IV glucose may worsen symptoms and increase thiamine requirements
Prevention of Wernicke’s encephalopathy: one pair of IVHP 5-ml ampoules once or twice daily for 3–5 days.

Treatment of Wernicke’s encephalopathy: Two pairs of IVHP 5-ml ampoules 8 hourly for 3 days. If no response is seen, discontinue therapy; if a response is seen, decrease the dose to one pair of ampoules daily for as long as improvement continues.When the Pabrinex course is finished, give oral thiamine 50–100 mg 8 hourly and 1–2 multivitamin tablets daily for the rest of admission. For severe vitamin B group deficiency, give 1–2 vitamin B compound strong tablets 8 hourly. A short course of folic acid may also be beneficial.

How not to give Pabrinex
Do not confuse the IV product with the IM preparation, nor the 5 and 10 ml product.

Adverse effects
Occasional hypotension and mild paraesthesia

Cautions
Anaphylactic shock rarely