14.Medicinal poisons

Acetylsalicylic Acid (Aspirin)

• Description:

  • Analgesic and antipyretic.

  • White crystalline powder with slight acidic taste.

• Action:

  • Stimulates respiratory centers; leads to hyperventilation and respiratory alkalosis initially.

  • Later causes metabolic acidosis by inhibiting Krebs cycle, amino acid metabolism, gluconeogenesis, and increasing lipid metabolism.

  • Neurotoxic.

• Fatal Dose: 15-20 gm

• Fatal Period: 6–8 hours

• It is absorbed from stomach and intestine, metabolized in the liver and excreted through urine

Signs and Symptoms

• Gastrointestinal (GIT):

  • Burning pain, nausea, vomiting.

• Central Nervous System (CNS):

  • Ataxia, hypothermia, coma, convulsions (salicylate jag), dilated pupils, hyperpyrexia.

• Cardiovascular (CVS):

  • Tachycardia, later rapid irregular pulse.

• Respiratory System (RS):

  • Tachypnea followed by Kussmaul's breathing.

• Hepatic Issues:

  • Reye's syndrome (especially in children <15 years).

    • Characterized by hepatic failure, encephalopathy, and neurological manifestations.

    • Symptoms can occur even with therapeutic doses.

    • Can lead to death or residual neurological issues.

• Blood:

  • Hemorrhagic manifestations.

• Musculoskeletal (MS):

  • Rhabdomyolysis and tetany.

Treatment

1. Stomach wash.

2. Activated charcoal.

3. Forced alkaline diuresis:

   • 100 meq sodium bicarbonate in 1 liter 5% dextrose saline solution.

4. Vitamin K.

5. Supportive treatment.

6. Hemodialysis or peritoneal dialysis.

7. Exchange transfusion.

Paracetamol (Acetaminophen)

• Description:

  • Commonly used as antipyretic and analgesic.

• Action:

  • Inhibits prostaglandin synthesis.

  • Hepatotoxic due to accumulation of N-acetyl-p-benzoquinone (NAPB).

  • Causes renal tubular necrosis.

• Fatal Dose: 10-15 gm.

• Fatal Period: 2-4 days.

Signs and Symptoms

• GIT:

  • Nausea, vomiting, upper abdominal pain.

• Hepatic:

  • Hepatic failure, jaundice, encephalopathy, hemorrhagic pancreatitis, bleeding.

• CNS:

  • Confusion, coma, convulsions.

Diagnosis

• Blood paracetamol level assessed by high-performance liquid chromatography (HPLC).

• SGPT > 1000.

• Rumack-Matthew nomogram helps in treatment planning.

Treatment

1. Stomach wash.

2. Activated charcoal.

3. Antidote:

   • N-acetyl cysteine (NAC) 150 mg/kg in 200 ml of 5% dextrose i.v. over 15 min.

4. Supportive measures.

Chloral Hydrate

• Description:

  • Known as Dry wine, still used in psychiatric hospitals as a hypnotic drug.

  • A combination with alcohol is known as Mickey Finn or knockout drops.

  • Appearance: Colorless crystalline powder with a pungent odor and bitter taste.

  • Common adulterant of toddy.

Action

• Causes depression of the central nervous system (CNS).

Absorption, Fate, and Excretion

• Absorption: Absorbed from the stomach and intestines.

• Metabolism: Metabolized in the liver.

• Excretion: Excreted through urine as trichloroethanol conjugated with glucuronic acid.

Signs and Symptoms

• Symptoms:

  • Nausea, vomiting, retrosternal burning pain, drowsiness, urticarial rash, jaundice.

  • Can lead to renal failure and death due to respiratory paralysis.

Dosage Information

• Fatal Dose: 3-5 gm.

• Fatal Period: 8-12 hours.

Treatment

• Flumazenil infusion up to 3 gm.

• Hemodialysis.