Common Medication Poisonings & Specific Antidotes
Comprehensive Substance Reference & Harm Reduction Guide
Common Medication Poisonings & Specific Antidotes
GUIDE-WIDE SAFETY NOTICE: This guide is for recognition, harm-reduction, and emergency-reference purposes. Appearance alone cannot reliably identify a substance. Counterfeit pills, powders, vapes, edibles, and street mixtures may contain unexpected drugs. Do not taste, smell closely, burn, or handle an unknown substance to identify it. If poisoning is possible, contact Poison Control (U.S. 1-800-222-1222) or 911 for severe symptoms.
11. Common Medication Poisonings & Specific Antidotes
| Substance | Appearance, Route & Intoxication | Physical Side Effects | Severe Toxicity / Overdose & Response |
| Acetaminophen (Tylenol) | Tablets, capsules, liquids. Oral. Early poisoning may cause mild nausea/vomiting or few symptoms. | Early nausea, vomiting, sweating, abdominal discomfort. Liver injury develops later. | Overdose: Fatal liver failure can occur after significant overdose, even after feeling better. Response: Contact Poison Control immediately, even if person feels well. Antidote: N-acetylcysteine (NAC) in hospital. 911 for severe illness. |
| Diphenhydramine (Benadryl) | Tablets, capsules, liquids. Oral. Drowsiness at standard doses; excess causes anticholinergic toxidrome. | Dry mouth, blurred vision, dilated pupils, fast heart rate, urinary retention, constipation. | Overdose: Delirium, hallucinations, fast heart rate, low BP, seizures, dangerous arrhythmias. Response: Poison Control for suspected excess; 911 for seizures, severe agitation, or collapse. |
| Antidepressants & Antipsychotics | Prescription tablets, capsules, injectables. Oral/injected. Toxicity varies by class; sedation, tremor, rapid heart rate. | Nausea, dizziness, sweating, tremor, drowsiness, BP changes, movement stiffness. | Overdose: Seizures, severe arrhythmias, blood pressure changes, coma, serotonin syndrome. Response: Call Poison Control promptly for overdose. 911 for severe symptoms, seizures, or collapse. |
| Beta Blockers & Clonidine | Prescription tablets, patches. Oral/transdermal. Dizziness, fatigue, slow pulse. | Slow heart rate, low blood pressure, dizziness, fatigue. | Overdose: Dangerously slow heart rate, profound shock, seizures, breathing difficulty. Response: Prompt Poison Control evaluation; 911 for fainting, seizures, or breathing problems. |
| Benzodiazepines (Hospital Antidote) | Prescription tablets. Oral. Sedation, slurred speech, poor coordination. | Drowsiness, muscle weakness, slowed reflexes. | Overdose: Deep unconsciousness, respiratory depression. Response: Hospital antidote: Flumazenil (receptor antagonist) can reverse sedation but is used cautiously due to acute withdrawal seizure risks in chronic users. |