title: Isoniazid poisoning: Pharmacokinetics and effect of hemodialysis in a massive ingestion.
abstract: Isoniazid is a rare overdose that causes seizures and there is limited evidence to guide treatment. We report a 20-year-old female migrant who presented with recurrent seizures after ingesting 25 g of isoniazid. She was treated with activated charcoal, repeated doses of midazolam for the seizures, and given multiple doses of pyridoxine (14 mg), limited by availability. She was admitted to intensive care, and 5.5 hours post-ingestion, she was commenced on continuous veno-venous hemodiafiltration (CVVHDF). She was extubated after 24 hours and CVVHDF was ceased 6 hours later (30 hours post-overdose). Her renal function remained normal and her initial lactate was the highest at 2.3. She made a full recovery. Five plasma samples were collected before, during, and after CVVHDF, and isoniazid was quantified with liquid chromatography-tandem mass spectrometry. A pharmacokinetic analysis of time-isoniazid concentration data was fitted to a two-compartment model with first-order input (with fixed ka ) with the effect of CVVHDF modeled as a time-dependent covariate. This suggested that there was initially good clearance with CVVHDF (4 times endogenous clearance), which rapidly declined within hours.
authors.affiliation: Emergency Medicine and Clinical Toxicology, Royal Perth Hospital, Perth, Western Australia, Australia.
authors.forename: Kirsty
authors.initials: K
authors.lastname: Skinner
authors.affiliation: School of Medicine and Public Health, University of Newcastle, Newcastle, New South Wales, Australia.
authors.forename: Ana
authors.initials: A
authors.lastname: Saiao
authors.affiliation: Therapeutics Research Centre, School of Medicine, University of Queensland, Brisbane, Queensland, Australia.|Pharmaceutical Chemistry Department, Faculty of Pharmacy, Helwan University, Cairo, Egypt.
authors.forename: Ahmed
authors.initials: A
authors.lastname: Mostafa
authors.affiliation: Emergency Medicine and Clinical Toxicology, Royal Perth Hospital, Perth, Western Australia, Australia.
authors.forename: Jessamine
authors.initials: J
authors.lastname: Soderstrom
authors.affiliation: Therapeutics Research Centre, School of Medicine, University of Queensland, Brisbane, Queensland, Australia.
authors.forename: Gregory
authors.initials: G
authors.lastname: Medley
authors.affiliation: Therapeutics Research Centre, School of Medicine, University of Queensland, Brisbane, Queensland, Australia.|School of Pharmacy and Medical Sciences, University of South Australia, Adelaide, South Australia, Australia.
authors.forename: Michael S
authors.initials: MS
authors.lastname: Roberts
authors.affiliation: School of Medicine and Public Health, University of Newcastle, Newcastle, New South Wales, Australia.|Department of Clinical Toxicology and Pharmacology, Calvary Mater Newcastle, Newcastle, New South Wales, Australia.
authors.forename: Geoffrey K
authors.initials: GK
authors.lastname: Isbister
mesh_terms: D000328:Adult; D062787:Drug Overdose / Q000150:complications*; D064420:Drug-Related Side Effects and Adverse Reactions / Q000150:complications*; D005260:Female; D006801:Humans; D007538:Isoniazid / Q000493:pharmacokinetics / Q000633:toxicity*; D006435:Renal Dialysis / Q000009:adverse effects*; D055815:Young Adult
chemical_list: D007538:Isoniazid
keywords: Isoniazid; hemodialysis; overdose; pharmacokinetics; poisoning; seizure