II. Indication: Drug Overdose with Weak Acid
- Phenobarbital or BarbiturateOverdose
- All Class I antidysrhythmic Overdose
- Tricyclic Antidepressant Overdose
- Antihistamine Overdose
- Cocaine Overdose
- Salicylate Overdose
- Chlorpropamide
- Chlorophenoxy Herbicides
- Sulfonamides (some)
- Methotrexate
- Fluoride Toxicity
- Diflunisal (Dolobid)
III. Contraindications
- Renal Failure
- Pulmonary Edema
- Cerebral edema
IV. Mechanism
- Enhances urinary excretion of weak acids
- Traps weak acids in ionized state (ion trapping)
- Prevents reabsorption by renal tubules
V. Medications: 8.4% Sodium Bicarbonate Solution with Potassium
- Sodium Bicarbonate 100 to 150 meq (2-3 ampules of 50 meq/50 ml vial)
- Add 20 to 40 meq Potassium (KCl) if not hyperkalemic
- Hypokalemia prevents urine alkalization
- Dissolve in D5W to total 1 liter volume
- Solution will be up to 8.4% Sodium Bicarbonate (0.1 to 0.15 meq/ml)
- Do not exceed 0.5 meq/ml concentration
VI. Dosing
- Use 8.4% Sodium Bicarbonate Solution with Potassium Solution as above
- Administer at 2 to 4 times maintenance IV rate
- Adult rate will be 200 to 400 ml/hour
- Adults would receive 20-30 to 40-60 meq/hour
- Do not exceed 1 meq/kg/hour
- Typically given over 2-3 hours
- Titrate to alkalizization
- Keep Urine pH at 7.5 to 8.0
- Keep serum pH normal (>7.40 up to 7.55)
- Keep Urine Output at 2-5 ml/kg/hour
- Monitoring
- Follow Serum Potassium closely
- Correct Hypokalemia if it occurs
VII. References
- (2005) Lexicomp Drug Database, Pocket PC Version
- Aaron in Stine (1994) Emergency Med, p.419
- Vega (2024) Am Fam Physician 109(2): 143-53 [PubMed]