0071643192.pdf

TOXICOLOGY

■ Activated charcoal: For large ingestions within 1–2 hours (with airway pro-

tection as needed)

■ Norepinephrine: For hypotension unresponsive to IVF

■ Intravenous magnesium sulfate, overdrive pacing, isoproterenol for torsades

■ Benzodiazepines: To control agitation and seizures

A 65-year-old male presents to the ED via EMS with weakness and dizzi-

ness. He has a history of depression, CHF, and HTN, and is on multiple

“heart” medications. Physical examination reveals sinus bradycardia,

hypotension, mild temperature depression, and normal mentation. Overdose of

which groups of cardiac drugs is suggested by this patient’s presentation?

Overdose of β-blockers, calcium channel blockers, clonidine, digoxin and

central-acting agents should be suspected in any patient presenting with

hypotension and bradycardia.

CARDIOVASCULAR MEDICATIONS

Antidysrhythmic Agents

Antidysrhythmic agents are classified via Vaughn-Williams into groups based on

electrophysiologic properties (see Table 6.14). Toxicity is unique to each class.

TABLE 6.13. Extrapyramidal Symptoms

NAME ONSET/REVERSIBILITY SYMPTOMS/EXAM TREATMENT

Akathisia Hours to days Anxiety Stop medication.

Reversible Acute motor restlessness Benzodiazepines

Diphenhydramine

Acute dystonia Hours to days after exposure Sustained muscle contractions → Stop medication.

Reversible facial grimacing. Benzodiazepines

Torticollis Diphenhydramine

Trismus

Laryngospasm

Opisthotonos

Parkinsonism Days to months of exposure Akinesia or bradykinesia ↓Dose or stop medication.

Usually reversible Masked facies Benztropine

Muscular rigidity

Tremor

Gait instability

Cognitive impairment

Tardive dyskinesia Months to years of exposure Involuntary, repetitive No specific treatment available

Usually irreversible orofacial, trunk and

extremity movements

Class IA and IC agents are

notorious for prolonging the

QRS and/or QT, causing VT or

torsades.