Repeat dosing may be needed for persistent seizure activity and may also be used to reverse deep coma. A low threshold should be used for pyridoxine administration in the setting of isoniazid toxicity. Peripheral neuropathy from the use of pyridoxine in doses of up to 52 g has not been reported. 9 One study 2 reported an absence of adverse effects with pyridoxine doses of up to 357 mg per kg. After the initial stabilization efforts, attempts should be made to prevent the absorption of isoniazid and to hasten elimination of the drug.
Gastric lavage is indicated if it can be done within one hour of isoniazid ingestion.
Charcoal, if administered within one hour of the ingestion of isoniazid, has been shown to be effective in preventing absorption of the drug. Charcoal should initially be given as a slurry with sorbitol. The sorbitol dose in adults is 1 to 2 g per kg, with a maximum dose of 150 g. In children, the sorbitol dose is 1.0 to 1.5 g per kg to a maximum dose of 50 g. If diazepam fails to control seizures or pyridoxine does not reverse coma, other interventions may be considered.