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OVERDOSE OF PHARMACEUTICAL AGENTS by PROF SHAHZAD MANZOOR.pptx
- 1. DR.PROF. MUHAMMAD SHEHZAD MANZOOR
- 4. Conventional antipsychotics Chlorpromazin e Haloperidol Droperidol Atypical antipsychotics Risperidone Olanzapine Ziprasidone Quetiapine aripiprazole
- 5. mainly act on CNS dopamine receptors atypical drugs also interact with serotonin receptors prolongation of QRS or QT intervals (or both) and can cause ventricular arrhythmias. Among the atypical agents, quetiapine is more likely to cause coma and hypotension.
- 6. Therapeutic doses of conventional phenothiazines induce drowsiness and mild orthostatic hypotension in as many as 50% of patients. Larger doses can cause Miosis Severe hypotension Tachycardia Convulsions, and coma
- 7. With therapeutic or toxic doses, an acute extrapyramidal dystonic reaction may develop in some patients, with Spasmodic contractions of the face and neck muscles, extensor rigidity of the back muscles, carpopedal spasm, Motor restlessness. .
- 8. Severe rigidity accompanied by hyperthermia and metabolic acidosis (“neuroleptic malignant syndrome”) may occasionally occur and is life-threatening .
- 9. Atypical antipsychotics have also been associated with weight gain and diabetes mellitus, including diabetic ketoacidosis.
- 10. Administer activated charcoal for large or recent ingestions. For severe hypotension, treatment with intravenous fluids and vasopressor agents may be necessary. Treat hyperthermia as outlined. Maintain ECG monitoring
- 11. Prolongation of the QT interval and torsades de pointes are usually treated with intravenous magnesium or overdrive pacing. For extrapyramidal signs, give diphenhydramine, 0.5–1 mg/kg intravenously, or benztropine mesylate, 0.01–0.02 mg/kg intramuscularly.
- 12. Bromocriptine (2.5–7.5 mg orally daily) may be effective for mild or moderate neuroleptic malignant syndrome. Dantrolene (2–5 mg/kg intravenously) has also been used For severe hyperthermia, rapid neuromuscular paralysis is preferred.
- 14. Edications used for diabetes mellitus Insulin Sulfonylureas and other Insulin secretagogues Alpha-glucosidase inhibitors (acarbose, miglitol), biguanides (metformin), Thiazolidinediones (pioglitazone, rosiglitazone) Sodium glucose transporter (SGLT2) inhibitors, and peptide analogs (pramlintide, exenatide) or enhancers (sitagliptin)
- 15. Insulin and the insulin secretagogue are the most likely to cause hypoglycemia. Metformin cancause lactic acidosis, especially in patients with impaired kidney function or after intentional drug overdose Hypoglycemia may occur quickly after injection of short acting insulins or may be delayed and prolonged
- 16. Give sugar and carbohydrate- containing food or liquids by mouth, or intravenous dextrose if the patient is unable to swallow safely. For severe hypoglycemia, start with D50W,50 mL intravenously (25 g dextrose) Consider hemodialysis for patients with metformin overdose accompanied by severe lactic acidosis
- 18. Cardiac glycosides paralyze the Na+- K+ -ATPase pump and have potent vagotonic effects. Intracellular effects include Enhancement of calcium-dependent contractility and Shortening of the action potential duration
- 19. nausea and vomiting bradycardia hyperkalemia AV block frequently occur
- 20. After acute ingestion, administer activated charcoal. Monitor potassium levels and cardiac rhythm closely. Treat bradycardia initially with atropine (0.5–2 mg intravenously) or a transcutaneous external cardiac pacemaker. Specific Treatment For patients with significant intoxication, administer digoxin-specific antibodies (digoxin immune Fab [ovine];DigiFab)
- 22. In therapeutic doses, nifedipine, nicardipine, amlodipine,felodipine, isradipine, nisoldipine, and nimodipine act mainly on blood vessels, while verapamil and diltiazem act mainly on cardiac contractility and conduction.
- 23. Bradycardia Atrioventricular (AV) nodal block Hypotension, or a combination of these effects. Hyperglycemia is common due to blockade of insulin release. With severe poisoning, cardiac arrest may occur
- 24. For ingested drugs, administer activated charcoal. In addition, whole bowel irrigation should be initiated as soon as possible if the patient has ingested a sustained-release product.
- 25. Treat symptomatic bradycardia with atropine (0.5–2 mg intravenously), isoproterenol (2–20 mcg/min by intravenous infusion), or a transcutaneous cardiac pacemaker. For hypotension, give calcium chloride 10%, 10 mL, or calcium gluconate 10%, 20 mL. Repeat the dose every 3–5 minutes.
- 26. BETA BLOCKER
- 27. hypotension and bradycardia. Cardiac depression from more severe poisoning is often unresponsive to therapy with beta-adrenergic stimulants such seizures and coma may occur. conduction disturbance (wide QRS interval) similar to tricyclic antidepressant overdose.
- 28. Attempts to treat bradycardia or heart block with atropine (0.5–2 mg intravenously), Isoproterenol (2–20 mcg/min by intravenous infusion, titrated to the desired heart rate), or an external transcutaneous cardiac pacemaker
- 29. Give Glucagon 5–10 mg intravenously, followed by an infusion of 1–5 mg/h. Glucagon is an inotropic agent that acts at a different receptor site and is therefore not affected by beta- blockade. High dose insulin (0.5–1 unit/kg/h intravenously) along with glucose supplementation has also been used to reverse severe cardiotoxicity.
- 31. Tricyclic and related cyclic antidepressants are among the most dangerous drugs involved in suicidal overdose. These drugs have anticholinergic and cardiac depressant proper ties (“quinidine-like” sodium channel blockade). Cardiotoxic effects
- 32. Signs of severe intoxication may occur abruptly and with out warning within 30–60 minutes after acute tricyclic overdose. Anticholinergic effects include: Dilated pupils, tachycardia, dry mouth, flushed skin, muscle twitching, and decreased peristalsis.
- 33. Quinidine-like cardiotoxic effects include QRS interval widening (greater than 0.12 s; ventricular arrhythmias AV block, hypotension. Rightward-axis deviation Prolongation of the QT interval and torsades de pointes have been reported Seizures and Hyperthermia may result from status epilepticus and anticholinergic-induced impairment of sweating.
- 34. Serotonin syndrome should be suspected if agitation,delirium, diaphoresis, tremor, hyperreflexia, clonus (spontaneous, inducible, or ocular), and fever develop in a patient taking serotonin reuptake inhibitors.
- 35. Observe patients for at least 6 hours and admit all patients with evidence of anticholinergic effects Administer activated charcoal and Consider Gastric lavage after recent large ingestions. All of these drugs have large volumes of distribution and are not effectively removed by hemodialysis procedures.
- 36. » • Boluses of sodium bicarbonate (50–100 mEq intravenously). Sodium bicarbonate provides a large sodium load that alleviates depression of the sodium-dependent channel • Prolongation of the QT interval or torsades de pointes is usually treated with intravenous magnesium or overdrive pacing. • Mild serotonin syndrome may be treated with benzodiazepines and withdrawal of the antidepressant.
- 37. Severe hyperthermia should be treated with neuromuscular paralysis and endotracheal intubation in addition to external cooling measures