Acute poisoning of antidepressants

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Acute poisoning of antidepressants

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Acute poisoning of antidepressants

  1. 1. TRICYCLIC ANTIDEPRESSANTS They have been employed in drug therapy since the late 1950s. Largest group of drug agents used for the treatment of depression. Referred as “ tri cyclic ” compounds –three rings.
  2. 2.  Due to both accidental and deliberate overdoses.  Life threatening ,high risk for suicide.  Involve multiple ingestions – ethanol , diazepam, codeine.  Toxicity due to rapid absorption , tight binding to plasma proteins , low therapeutic margins.
  3. 3. TRICYCLIC ANTIDEPRESSANT DRUGS  Secondary amines: -Amoxapine , Nortriptyline , Desipramine , Protriptyline.  Tertiary amines:-Amitriptyline , Imipramine,Doxepin,Trimipramine.  Tetra cyclic:- Maprotiline.  Triazolopyridine :-Trazodone.
  4. 4. MECHANISM  Decreases the action of acetylcholine centrally and peripherally.  Enhances dopamine levels.  Reduced serotonin uptake resultant increase within the synapse.  Respiratory dysfunction and disturbances in body temp- respiratory center , thermoregulatory site.
  5. 5. CNS CARDIOVASCULAR ANTICHOLINERGIC HYPOTHERMIA VENTRICULAR RATE ≥120 BEATS/MIN MYDRIASIS RESPIRATORY DEPRESSION ARRHYTHMIAS BLURRED VISION SEIZURES BUNDLE BRANCH BLOCK TACHYCARDIA ABNORMAL TENDON REFLEXES CARDIAC ARREST URINARY RETENTION AGITATION HYPOTENSION VASODILATION DISORIENTATION CIRCULATORY COLLAPSE DECREASED GI MOTILITY MYOCLONIC JERKS DECREASED BRONCHIAL SECREATIONS COMA DRY MUCUS MEMBERANE AND SKIN PYRAMIDAL SIGNS
  6. 6. CNS EFFECTS  Geriatric patients and alcoholics- confusion, agitation and nervousness.  Coma  Elderly patients –memory deficit.  Amitriptyline- acute dystonia and extra pyramidal symptoms.
  7. 7. SEIZURES  Occur soon after admission.  Lead to hypotension , cardiovascular deterioration and death.  Amoxapine , Maprotiline overdose.
  8. 8. PERIPHERAL NERVOUS SYSTEM  Amitriptyline overdose- peripheral neuropathies and polyradiculoneuropathy. RHABDOMYOLYSIS  Seizures and coma PULMONARY EDEMA  Develop between 5 & 48 hours after ingestion.  Respiratory distress syndrome and pulmonary injury.
  9. 9. GASTRO INTESTINAL  Overdose in Elderly – acute intestinal pseudo obstruction ,fecal peritonitis. WITHDRAWAL SYMPTOMS: Anorexia,nausea,emesis,diarrhoea,malaise , headache,chills,fatigue,anxiety,insomnia, parkinsonism and mania.
  10. 10. TREATMENT  Immediately evaluate the patient and administer oxygen.  Monitor vital signs.  STABILISATION – Insert an intravenous line and cardiac monitoring. Altered mental status- naloxone, glucose and if indicated thiamine. Adequate ventilation ,prolonged cardiac massage.
  11. 11.  SUPPORT VITAL FUNCTIONS: Respiratory depression – intubation and hyperventilation Hypotension- Nor epinephrine , Phenyl epinephrine. Sodium bicarbonate . Glucagon(10mg bolus followed by an infusion of 10 mg over 6 hours) . Dysrhythmias- sodium chloride.
  12. 12.  REDUCE TCA ABSORPTION:- Ipecac or gastric lavage within 6 hrs. Activated charcoal (1g/kg) in all cases.  INCREASE TCA ELIMINATION:- Multiple doses of activated charcoal (0.5-1.0 g/kg)
  13. 13.  TREAT CONVULSIONS:- Diazepam(0.1 mg/kg iv). Phenytoin infusion (15 mg/kg iv) over 30 min . SEIZURES:- Benzodiazepines , Phenobarbital (15-20 mg/kg).
  14. 14.  OBSERVE ECG CHANGES :- TREAT ARRHYTHMIAS –  Sinus tachycardia-supportive measures only. Ventricular tachycardia – Alkalinize pH 7.45-7.5 . Lignocaine (1 mg/kg iv bolus then infusion 2-4 mg/min). Isoprenaline infusion(0.5- 5.0µg/min).
  15. 15.  SUPRAVENTRICULAR ARRHYTHMIAS- Alkalinize pH 7.4-7.5  VENTRICULAR FIBRILLATION- Defibrillate. Sodium bicarbonate (1-3 mmol/kg). Hyperventilation pH 7.45-7.5 . 1:1000 Adrenaline (0.5-1.0 mg iv). Lignocaine . Beta blockers if these measures are ineffective.
  16. 16.  BRADYCARDIA : Alkalinize pH 7.4-7.5 Isoprenaline . Pacemaker.  REFRACTORY CARDIAC ARREST: Basic and advanced life support for 1hr. Alkalinize pH 7.5 .  VENTRICULAR ARRHYTHMIAS: Lidocaine , Magnesium sulphate infusion 3- 20mg/min , Magnesium 2g i.v .
  17. 17.  ANTIDOTE:- Anti- Imipramine antibodies. Titrations with Fab. Anti -TCA monoclonal antibody. Combination of Anti -TCA Fab and Sodium bicarbonate.
  18. 18. DISCHARGE CRITERIA  Observed for 6 hrs.  If no abnormality in vital functions , discharged after a final dose of charcoal.  Persistent Tachycardia should be evaluated.
  19. 19. REFERENCES 1. MATHEW .J. ELLENHORN. ELLENHORNS MEDICAL TOXICOLOGY – DIAGNOSIS & TREATMENT OF POISONING, 2nd EDITION, WILLIAMS AND WILLKINS PUBLICATION, LONDEN, Pg No:626- 636. 2. PRINCIPLES OF CLINICAL TOXICOLOGY BY THOMAS .A.GOSSEL & J.DOUGLAS BRICKER, 2nd EDITION, Pg No:301-303.

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