Details About Overdose or Poisoning Generic Salt :: Pyridoxine, Vitamin B6
Pyridoxine (Vitamin B6)
Drug Pharmacology ::
I. Pharmacology. Pyridoxine (vitamin B6)is a water-soluble B-complex vitamin that acts as a cofactor in manyenzymatic reactions. Overdose involving isoniazid or othermonomethylhydrazines (eg, Gyromitra mushrooms) may causeseizures by interfering with pyridoxine utilization in the brain, andpyridoxine given in high doses can control these seizures rapidly andmay hasten consciousness. It can also correct the lactic acidosissecondary to isoniazid-induced impaired lactate metabolism. In ethyleneglycol intoxication, pyridoxine may enhance metabolic conversion of thetoxic metabolite glyoxylic acid to the nontoxic product glycine.Pyridoxine is well absorbed orally but usually is given intravenouslyfor urgent uses. The biologic half-life is about 15–20 days.
Drug Indications ::
Indications
Acute management of seizures caused by intoxication with isoniazid (see Isoniazid (INH)), hydrazine, Gyromitramushrooms (Mushrooms, Amatoxin-Type), or possibly cycloserine.Pyridoxine may act synergistically with diazepam (Benzodiazepines[Diazepam, Lorazepam, and Midazolam]).
Adjunct to therapy for ethylene glycol intoxication.
May improve dyskinesias induced by levodopa.
Drug Contra-Indications ::
III. Contraindications. Use caution in patients with known sensitivity to pyridoxine or parabens preservative.
Drug Adverse Effects ::
IV. Adverse effects
Usually no adverse effects are noted from acute dosing of pyridoxine.
Chronic excessive doses may result in peripheral neuropathy (see Neuropathy).
C. Useof the 1-mL vials may cause mild CNS depression owing to thepreservative if 50 or more vials (to deliver 5 g or more of pyridoxine)are administered (equivalent to 250 mg or more of chlorobutanol).
Use in pregnancy. FDAcategory A (see Table III–1). However, chronic excessive use inpregnancy has resulted in pyridoxine withdrawal seizures in neonates.
Drug Lab Interactions ::
Drug or laboratory interactions. No adverse interactions are associated with acute dosing.
Drug Dose Management ::
Dosage and method of administration
Isoniazid poisoning. Give1 g of pyridoxine intravenously for each gram of isoniazid known tohave been ingested (as much as 52 g has been administered andtolerated). Dilute in 50 mL dextrose or saline and give over 5 minutes(rate of 1 g/min). If the ingested amount is unknown, administer 4–5 gIV empirically and repeat every 5–20 minutes as needed.
Monomethylhydrazine poisoning. Give 25 mg/kg IV; repeat as necessary.
Ethylene glycol poisoning. Give 50 mg IV or IM every 6 hours until intoxication is resolved.
Cycloserine poisoning. A dosage of 300 mg/day has been recommended.
Drug Chemical Formulations ::
Formulations
Parenteral. Pyridoxinehydrochloride (various), 100 mg/mL (10% solution) in 1- and 30-mL vials(1-mL vial contains the preservative chlorobutanol, and 30-mL vialcontains parabens). Note: Only one US company, LegerePharmaceuticals (Scottsdale, AZ; phone: 800-528-3144), manufactures anddistributes the 3-g (30-mL) vials. See adverse effects above regardinguse of the 1-mL vials.
The suggested minimum stocking level to treat a 70-kg adult for the first 24 hours is 20 g (7 vials, 30 mL each, or the equivalent).
