- The patient is a 25-year-old Thai woman who presented to the emergency room after ingesting an unknown medication belonging to her sister about 1 hour prior due to a severe headache. She experienced nausea, vomiting, and drowsiness. - On examination, she appeared drowsy with normal vital signs. ECG showed no abnormalities. Laboratory tests revealed no abnormalities except mild anemia. Drug screening of blood and gastric content was negative. - The leading diagnosis was toxicity from a sodium channel blocking agent. Management included activated charcoal, sodium bicarbonate, and supportive care. The patient's condition improved with treatment.

1. Case Conference December 15, 2007

7. Problem list & differential diagnosis

9. Investigation

10. 23/9/50 20.06

11. EKG

19. 23/9/50 20.33 ( after injection of NaHCO3)

20. 23/9/50 21.22

21. 23/9/50 22.39

22. 24/9/50 08.56

26. Drug with Na channel blockade property (membrane stabilizing effect) Amantadine Amitryptyline Amoxapine Carbamazepime Chloroquine Cocaine Imipramine Loxapine Maproyiline Nortryptyline Orphenadrine Phenothaizine Desipramine Diltiazem Diophenhydramine Encainide Flecainide Hygroxychloroquine Procainamide Propanolol Thioridazine Quinidine Quinine Verapamil Note; Many Na channels blocking agents also bind to K channels and prevent efflux: Phenothiazine, antihistamines, and type A antidysrhythmics (7)

31. Chloroquine Intoxication

34. Pathophysiology Severe chloroquine poisoning is usually associated with ingestions of 5 g or more in adults, or with serum concentrations exceeding 5 mg/L. Goldfrank_s_Toxicologic_Emergencies__8e_2006

35. The cardiovascular effects QRS prolongation: block fast Na channel of perkinje fiber and his bundle  delay depolarization, QTc interval prolongation, increased U wave: in inhibit K efflux  delay repolarization Goldfrank_s_Toxicologic_Emergencies__8e_2006 Pathophysiology VT : delayed depolarization ที่ไม่พร้อมกันของเซลล์กล้ามเนื้อหัวใจที่ ventricle ทำให้เกิด reentry circuit และเกิดเป็น VT ตามมา Torsades depointes: prolong QT

37. Clinical Manifestations Symptoms usually occur within 1- 3 hours of ingestion Respiratory depression Hypotension Cardiovascular compromise Significant hypokalemia results from direct chloroquine-induced intracellular shifts . Goldfrank_s_Toxicologic_Emergencies__8e_2006

38. The neurologic manifestations include CNS depression, dizziness, headache, and convulsions. Rarely. Clinical Manifestations Red blood cell (RBC) oxidant stress from chloroquine may result in hemolysis in patients with glucose-6-phosphate dehydrogenase (G6PD) deficiency Goldfrank_s_Toxicologic_Emergencies__8e_2006

40. Management Patients should receive early endotracheal intubation and mechanical ventilation : if arrhythmias, hypotension, seizures or significant CNS depression are present Inotropes may also be necessary : for hypotension unresponsive to a fluid challenge ( 1) thiopental was used to facilitate intubation, its use immediately preceded sudden cardiac arrest in 7 of 25 patients after chloroquine overdose.(1) 1. ABC epinephrine (0.25 mcg/kg/min) should be given IV with D 5 W, and adjusted incrementally until a systolic blood pressure greater than 100 mm Hg (1)

42. 2. GI decontamination Management Orogastric lavage: within 1 hour after ingestion Activated charcoal : 1 g/kg Goldfrank_s_Toxicologic_Emergencies__8e_2006

44. If the QRS complex width is increased, sodium bicarbonate should be administered Management Goldfrank_s_Toxicologic_Emergencies__8e_2006 Chloroquine significant protein binding, and long terminal elimination half-lives, enhanced elimination procedures are not beneficial

53. Thank you For your attention Merry Christmas and Happy New Year 2008