Tox: Tricyclic Antidepressant Overdose

Tox: Tricyclic Antidepressant Overdose

-most drug related deaths than any other rx
-myocardial sodium channel antagonism
-10mg/kg is life threatening

si/sx
-within 6hr
-hypotn, resp depression, cardiac dysrhythmias, dry mucosae, diminished bowel sounds, urinary retention, ms changes, sz's
-EKG - qrs >100 ms, RAD of the terminal 40ms >120 deg (R in AVR, S in I), indicates life-threatening complication

Labs:
-UDS/SDS (with TCA level), LFT's, CBC, lytes, bun, cr, glc, U/A

rx:
-Vitals, O2, monitor, IV, airway
-Place single-lumen nasogastric tube and lavage with 2 liters of normal saline if recent ingestion.
-Activated charcoal premixed with sorbitol 50 gm via NG tube q4-6h until the TCA level decreases to therapeutic range. Maintain head-of-bed at 30-45 degree angle to prevent charcoal aspiration.
-Magnesium citrate 300 mL via nasogastric tube x 1 dose.
-hypotn - start with fluids NS?/LR, bolus 2L first
-sod bicarb1-2meq/kg IV (50-100mEq=1-2amps) over 5-10min, followed by inf 2-3 amps sod bicarb in 1 L D5W rate 3 cc/kg/h (100-150 cc/hr) for QRS >100ms, hypotn refractory to IV fluids, vent dysrhythmias; must monitor potassium. Adjust rate to maintain pH 7.50-7.55.
-norepi infusion if refractory to fluids, bicarb
-also can use neosynephrine (phenylephrine), dobutamine
-neurochecks q1h, cont suicide obs, ECG monitoring with hourly QRS width measurements, asp and sz precautions
-If mechanical ventilation is necessary, hyperventilate to maintain pH 7.50- 7.55.