A Patient taking overdose of sleeping pills

By Dr WL Yip, AED, QMH

Case report

• F / 28, good past health

• Taken 30tabs of ‘sleeping pills’

• suicidal attempt

• Drowsy, and brought to private hospital by friends within 1 hour

Clinical findings

• GCS E4 V1 M5 10/15

• Pupil E&R 2mm

• ECG sinus tachycardia 142/min

• PR 145, QRS 81, QTc 339

ECG

Management

• Gastric lavage• Activated charcoal 50gm

• Witnessed generalized seizure (last ~30sec) 1 hour after ingestion, resolved spontaneously

• Transferred to AED after stablized• (within 2 hours after ingestion)

Progress in AED

• BP 130/65, P 130

• Temp 36.5

• H’stix 6.6

• GCS E4 V1 M5 10/15

• ECG sinus tachycardia 123/min

• PR 144, QRS 82, QTc 389

• Admit medical

Progress in ward

• Stable all along

• Blood test unremarkable

• Toxicology: BDZs, diphenhydramine

• Fully conscious next day

• Seen by psychiatrist: adjustment disorder

• Discharged home

Unisom SleepGel

• Contain diphenhydramine 50mg in each tablet

Diphenhydramine overdose

• First-generation antihistamines

• H1-blockers

• Ethanolamine

• Dose-dependent toxicity

• Ingestion >1gm at risk developing severe symptoms

Anticholinergic syndromes

• Peripheral (dry mucous membrane, hot, dry and flushed skin, peripheral vasodilation, dilated pupil, blurred vision, urinary retention, intestinal ileus, sinus tachycardia)

• Central (disorientation, agitation)

Seizures

• Not common

• Generally short-lived

• May be prolonged / repeated if large dose taken

Other CNS effects

• Sedation

• Catatonic stupor (highly specific)

• Acute extrapyramidal movement disorders

• Anxiety

• Toxic psychosis

Cardiac toxicity

• Sinus tachycardia

• Quinidine-like conduction abnormalities

• Slow sodium channels conduction result in decreased conduction and contractility

• Associated prolonged QT

Other rare features

• Rhabdomyolysis

• Hyperthermia

• Ventricular tachycardia

Management

• ABC

• Activated charcoal

• Gastric lavage – Consider even after 1 hour since diphenhydramine

decreases your gut motility

Treatment of agitation

• Due to anti-cholinergic effects

• Benzodiazepines

• Physostigmine (if no conduction disturbance)

Cardiovascular toxicity

• No treatment for sinus tachycardia

• Intravenous sodium bicarbonate for conduction abnormalities

Prognosis

• Most recovered with supportive treatment and observation

Learning Points

• We should consider the potential risk of aspiration if we perform GL in patient with impaired conscious level and at risk of developing convulsionAirway protection should be ensured

• Precautions and potential advantages in using physostigmine for the treatment of anti-cholinergic poisoning

(Burns et al, Ann Emerg Med. April 2000;35:374-381)

Thank you