Pyridoxine / Vitamin B6
Liverpool Hospital Emergency Department
Indications:
- Isoniazid overdose
- Ethylene Glycol overdose (cofactor in glyoxylic acid metabolism)
Formulation:
- IV 50mg/ml
- PO 25mg /50mg/ 100mg
Dosage and Administration
- Isoniazid Overdose
- Intravenous:
- Dosage is equivalent to amount of Isoniazid ingested 1:1 ratio (e.g. 4g isoniazid requires 4g of pyridoxine)
- Maximum dose is 5g via infusion at a rate of 500mg/minute.
- Seizures, acidosis or unknown dose and very unwell should be managed with pyridoxine – 5g IV
- Oral:
- Dosage is equivalent to the amount of Isoniazid ingested 1:1 ratio
- Charcoal will reduce bioavailability of oral pyridoxine
- Ethylene glycol overdose:
- 50mg IV 6 hourly for 2 days (thiamine is an alternative)
Side Effects:
- Chronic high doses can cause peripheral neuropathy
- Hypersensitivity can occur
Pit Falls:
- Low dose available therefore po may be a more viable alternative
- If insufficient IV dosing available and seizures are present consider benzodiazepines and barbiturates. (Other anticonvulsants are not effective)