Mwandishi:
ULY CLINIC
Mhariri:
ULY CLINIC
Imeboreshwa:
20 Oktoba 2026, 15:06:27
Common poisons
A poison is any substance — whether liquid, solid, or gas — that produces harmful physiological effects or tissue injury when it enters the body through ingestion, inhalation, injection, or absorption across the skin or mucous membranes.
Globally, poisoning remains a major public-health problem, particularly in low- and middle-income countries where:
pesticides are widely available,
fuels are stored in drink containers,
medications are easily accessible,
and traditional medicines are commonly used.
In many East African settings, the most frequent causes of poisoning include:
pesticides (especially organophosphates),
hydrocarbons (kerosene),
medications,
contaminated foods,
snake and envenomation-related toxins.
Poisoning may be:
Accidental — especially in children
Intentional — self-harm in adolescents/adults
Occupational — agricultural or industrial exposure
Always suspect poisoning in any sudden unexplained illness in a previously healthy person.
Common Sources of Poisoning
1. Household Agents
Organophosphates (e.g. malathion insecticides)
Rat poison
Disinfectants and bleach
Hydrocarbons (kerosene, petrol, turpentine)
2. Medications
Analgesics (paracetamol, aspirin)
Anticonvulsants (carbamazepine)
Hematinics (iron tablets)
Antipsychotics (major tranquilizers)
Sedatives and benzodiazepines
Herbal and traditional remedies
3. Food Poisoning
Toxic mushrooms
Contaminated food
Bacterial toxins
4. Recreational / Illicit Drugs
Sympathomimetic agents
Cocaine
Amphetamines
LSD
PCP
5. Agricultural Chemicals
Cholinergic toxins
Organophosphates
Carbamates
Risk Factors
Patient Factors
Children under 5 years
Psychiatric illness
Substance abuse
Suicide attempts
Elderly with polypharmacy
Chronic liver or kidney disease
Environmental Factors
Unsafe storage of chemicals
Unlabeled containers
Agricultural occupation
Traditional medicine use
Low literacy
Signs and Symptoms
Symptoms depend on the toxidrome (pattern of toxicity) rather than the specific poison.
1. General Symptoms
Nausea
Vomiting
Abdominal pain
Dizziness
Weakness
2. Sympathomimetic Toxidrome
(Stimulant poisoning)
Feature | Findings |
CNS | Agitation, psychosis, seizures |
CVS | Tachycardia, hypertension |
Skin | Sweating |
Pupils | Dilated |
Temp | Hyperthermia |
3. Cholinergic Toxidrome
(Organophosphate poisoning)
SLUDGE syndrome
Salivation
Lacrimation
Urination
Diarrhea
Gastrointestinal cramps
Emesis
Additional:
Miosis
Bradycardia
Bronchospasm
Respiratory failure
4. CNS Depressant Toxidrome
Reduced consciousness
Slow breathing
Hypotension
Coma
5. Anticholinergic Toxidrome
Dry skin
Hot flushed skin
Dilated pupils
Delirium
Urinary retention
Diagnostic Criteria
Diagnosis is primarily clinical.
A patient is considered poisoned if:
Sudden unexplained illness
Exposure history or suspicion
Toxidrome present
Supporting laboratory abnormalities
Investigations
Baseline Tests (All Patients)
Random blood glucose
Serum electrolytes
Renal function tests
Liver function tests
Full blood count
Arterial blood gas
ECG monitoring
Sympathomimetic Toxidrome Work-up
ECG
Creatine kinase
Coagulation profile (PT/PTT/INR)
Serum osmolality & osmolar gap
Toxicology screen
Abdominal X-ray (drug packets)
Additional Tests Depending on Poison
Drug levels (paracetamol, salicylate, lithium)
Chest X-ray (aspiration)
CT brain (persistent coma)
Treatment
Management follows a holistic structured approach
Non-Pharmacological Management
1. Resuscitation (Always First)
Airway protection
Oxygen therapy
IV access
Cardiac monitoring
Correct hypoglycemia
Control seizures
2. Decontamination
Remove contaminated clothes and wash exposed skin.
Forced vomiting is not recommended.
Gastric lavage only in life-threatening poisoning within 30 minutes to 1 hour of ingestion when no safer method is available and the airway is protected.
A: Activated charcoal (PO or NG tube), single dose, within 1 hour of ingestion, only if the airway is protected: children below 1 year 1 g/kg; children 1–12 years 25–50 g; adolescents and adults 25–100 g.
Mix the charcoal in 8–10 times its amount of water (for example 5 g in 40 ml); give it all at once, or divide the dose if the child cannot tolerate it.
Multiple doses of activated charcoal are indicated for carbamazepine, dapsone, digoxin, paraquat, phenobarbitone, quinine, slow-release preparations such as theophylline, and Amanita phalloides mushrooms, and may be considered in life-threatening overdose of other drugs such as tricyclic antidepressants.
Do not give activated charcoal for corrosives or petroleum products (kerosene, petrol).
3. Supportive Care
IV fluids
Temperature control
Ventilatory support
Observation 4–24 hrs minimum
Pharmacological Management
1. Antidotes (If Known)
Poison | Antidote and dose (STG 2026) |
Organophosphates (malathion, dichlorvos, dimethoate and others) | A: Atropine 2–5 mg IV (adults) or 0.05 mg/kg IV (children), doubling every 3–5 minutes until atropinised (dry secretions, heart rate above 80, systolic BP above 80 mmHg) AND S: pralidoxime 1–2 g IV over 15–30 minutes, repeat after 1 hour then 12-hourly as needed, OR 30 mg/kg IV over 20 minutes then 4–8 mg/kg/hour |
Carbamates (propoxur, aldicarb, carbaryl, carbofuran, methomyl) | A: Atropine 2–5 mg IV (adults) or 0.05 mg/kg IV (children), titrated to atropinisation; pralidoxime is usually not needed for carbamates |
Organochlorines (endosulfan, lindane, heptachlor, chlordane) | Supportive care |
Anticoagulant rodenticides (bromadiolone) | B: Phytomenadione (vitamin K1) 2.5–10 mg PO/SC in adults, up to 25–50 mg if needed, repeated every 12–48 hours; S: cholestyramine 4 g PO every 12–24 hours (maintenance 8–16 g/day, maximum 24 g/day) |
Arsenic | D: Dimercaprol 3 mg/kg IM every 4 hours for 48 hours, then 3 mg/kg every 12 hours for 10 days AND D: penicillamine 30–40 mg/kg/day PO for 1–6 months (2 hours before or 3 hours after food) |
Methanol | Ethanol: loading 600 mg/kg IV or 600–700 mg/kg PO/NG (diluted); maintenance 0.15 ml/kg/hour (IV: 1.4 ml/kg/hour of 10% ethanol) |
Ethylene glycol (antifreeze) | Ethanol as for methanol AND S: folinic acid 60 mg IM once, then 15 mg PO every 8 hours for 48–72 hours AND C: thiamine 100 mg IV once, then 50–100 mg/day IM/IV |
Cyanide | C: Hydroxocobalamin 70 mg/kg IV (usually 5 g) over 15 minutes; repeat 5 g if needed |
Methaemoglobinaemia (nitrites, nitrates, dapsone, aniline, naphthalene) | C: Methylene blue 1 mg/kg IV over 5–30 minutes; repeat after 1 hour if methaemoglobin is above 30% or symptoms persist |
Paracetamol | C: N-acetylcysteine (IV 21-hour regimen; oral 140 mg/kg loading, then 70 mg/kg every 4 hours for 3 days) |
Iron | D: Deferoxamine 50 mg/kg IM every 4–12 hours (moderate) or 15 mg/kg/hour IV infusion (severe) |
Benzodiazepines | D: Flumazenil 0.2 mg IV over 15 seconds, then 0.1 mg every 60 seconds until awake (usual total 0.3–0.6 mg) |
Opioids | B: Naloxone 0.4–2 mg IV, repeated every 2–3 minutes as needed |
Isoniazid | B: Pyridoxine 10–25 mg PO every 8 hours for 48 hours |
Digoxin | S: Digoxin immune Fab (1 vial binds 0.5 mg digoxin) |
Datura (anticholinergic plant) | S: Physostigmine 0.5–2 mg IV slowly (maximum 1 mg/min), repeat after 20 minutes if needed; maintenance 1–4 mg every 30–60 minutes as needed |
Snake bite | A: Polyvalent snake venom antiserum IV: mild 5 vials, moderate 5–10 vials, severe 10–20 vials |
Dog bite (rabies exposure) | B: Human rabies immunoglobulin, half infiltrated into the wound and half IM/SC |
Botulism | S: Botulinum antitoxin IV, starting at 0.5 ml/min for 30 minutes, then slowly with monitoring for hypersensitivity |
Call the National Poison Control Centre on the toll-free number 0800 112031 for advice.
2. Symptom-Based Therapy
Benzodiazepines for seizures
Vasopressors for shock
Sodium bicarbonate for acidosis
Dialysis for dialyzable toxins
3. Psychosocial Intervention
Suicide risk assessment
Psychiatric referral
Counseling
Family education
Prevention
Do’s
Store chemicals safely
Use child-resistant containers
Keep original packaging
Read labels carefully
Don’ts
Do not transfer chemicals to drink bottles
Do not remove labels
Do not leave containers open
Do not call medicine sweets
Avoid taking medication in front of children