Question:medium
A 30-year-old female abuser with suicidal tendency brought to hospital. Mydriasis, tachypnea, tachycardia +. Diagnosis
A 30-year-old female abuser with suicidal tendency brought to hospital. Mydriasis, tachypnea, tachycardia +. Diagnosis
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Mydriasis + tachypnoea + tachycardia = a sympathomimetic toxidrome – the opposite of the opioid (pinpoint pupil, slow breathing) picture.
Updated On: Jun 22, 2026
- Cocaine
- Morphine
- Heroin
- Chlorpheniramine
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The Correct Option is A
Solution and Explanation
Toxidrome-pattern recognition.
The fastest way to read a poisoning case is to assign it to a toxidrome. This patient has dilated pupils (mydriasis), rapid breathing (tachypnoea) and a fast pulse (tachycardia) - i.e. widespread sympathetic over-activity, the sympathomimetic / stimulant toxidrome.
Why cocaine: Cocaine blocks reuptake of the catecholamines (noradrenaline, dopamine) and serotonin at the synapse, flooding receptors and producing exactly this stimulant picture - mydriasis, tachycardia, hypertension, tachypnoea, hyperthermia, euphoria and agitation. In an abuser with suicidal intent, cocaine overdose neatly explains all three signs.
Contrast - the opioids: Morphine and heroin generate the opioid toxidrome, which is the mirror image: miosis (pinpoint pupils), depressed respiration and bradycardia/CNS depression. Since the patient has DILATED pupils with FAST breathing and pulse, opioids are excluded.
Contrast - the antihistamine: Chlorpheniramine is an anticholinergic-type sedating antihistamine; its overdose toxidrome is anticholinergic (dry, hot, flushed skin, urinary retention, delirium) and CNS depression, which does not match a clean sympathomimetic triad as well as cocaine.
So the sympathomimetic triad in a drug abuser is best explained by cocaine.
Answer: A (Cocaine).
The fastest way to read a poisoning case is to assign it to a toxidrome. This patient has dilated pupils (mydriasis), rapid breathing (tachypnoea) and a fast pulse (tachycardia) - i.e. widespread sympathetic over-activity, the sympathomimetic / stimulant toxidrome.
Why cocaine: Cocaine blocks reuptake of the catecholamines (noradrenaline, dopamine) and serotonin at the synapse, flooding receptors and producing exactly this stimulant picture - mydriasis, tachycardia, hypertension, tachypnoea, hyperthermia, euphoria and agitation. In an abuser with suicidal intent, cocaine overdose neatly explains all three signs.
Contrast - the opioids: Morphine and heroin generate the opioid toxidrome, which is the mirror image: miosis (pinpoint pupils), depressed respiration and bradycardia/CNS depression. Since the patient has DILATED pupils with FAST breathing and pulse, opioids are excluded.
Contrast - the antihistamine: Chlorpheniramine is an anticholinergic-type sedating antihistamine; its overdose toxidrome is anticholinergic (dry, hot, flushed skin, urinary retention, delirium) and CNS depression, which does not match a clean sympathomimetic triad as well as cocaine.
So the sympathomimetic triad in a drug abuser is best explained by cocaine.
Answer: A (Cocaine).
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