Valproic acid metabolic acidosis

Bismuth Subsalicylate (Pepto-Bismol) [Antidiarrheal/ Adsorbent] [OTC] Uses Indigestion, N, D combo for Rx of H. pylori Infxn Action Antisecretory anti-inflammatory E>o e Adults. 2 tabs or 30 mL PO PRN (max 8 doses/24 h) Feds. 3—6 y 1/3 tab or 5 mL PO PRN (max 8 doses/24 h) 5-9 y 2/3 tab or 10 mL PO PRN (max 8 doses/24 h) 9-72 y 1 tab or 15 mL PO PRN (max 8 doses/24 h) Caution [C, D (3rd tri), -] Avoid w/ renal failure Hx severe GI bleed Contra Influenza or chickenpox (T risk of Reye synd), ASA allergy (see Aspirin) Disp Chew tabs, caplets, Liq, susp SE May turn tongue stools black Interactions T Effects OF ASA, MTX, valproic acid effects OF tetracyclines i effects W/ corticosteroids, probenecid EMS Monitor for hypovolemia and electrolyte disturbances d/t D may darken tongue stool OD Similar to ASA OD V, tinnitus, metabolic acidosis activated charcoal may be effective... 

Fanconi syndrome (metabolic acidosis secondary to malfunction of proximal renal tubules, resulting in urinary excretion of amino acids, glucose, phosphate, bicarbonate, uric acid, and other substances) secondary to longterm valproic acid has been described in an 8-year-old boy with severe developmental disability (1170). In a review of 10 previous reports of Fanconi syndrome secondary to long-term valproic acid therapy the authors found that all occurred at 4-14 years, all had taken valproic acid for 10 months to 10 years, and symptoms were fully reversible within 2-14 months after withdrawal of valproic acid. Most of the patients (9 of 11) were severely disabled, bedridden, or wheelchair-bound. 

After a valproate overdose a 27-year-old man developed seizures, hypernatremia, respiratory failure, metabolic acidosis, liver failure, and bone marrow depression (125). His plasma valproic acid concentration was 1414 pg/ml. Treatment with hemodialysis was effective in enhancing valproic acid clearance, while hemoperfu-sion was relatively less effective, because of saturation of the column. Overall, the half-Ufe of the drug was reduced from over 20 hours before treatment to less than 3 hours during hemodialysis/hemoperfusion drug removal was probably favored by saturation of drug binding to plasma proteins, which resulted in a low unbound fraction (32% at the start of treatment). He was comatose for 5 days but recovered fully thereafter. 

Drug overdose Of 16 796 toxic exposures to antiepileptic drugs (phenytoin, valproic acid, and carbamazepine) in the USA in 2006, 12 resulted in death, as reported by the US Toxic Surveillance System [67 ]. Some specific problems determined by overdose of some old and new antiepileptic drugs have been briefly reviewed. For example, topiramate can cause a significant metabolic acidosis, lamotrigine Stevens-Johnson syndrome, oxcarbazepine hyponatremia, and levetiracetam psychosis. Possible adoption of guidelines for critical care management of overdose are discussed. 

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