Case Study in CBZ toxicity

1. Case Study on Carbamazepine Poisoning NeerajOjha YuvrajKalathoki 7thsem BPHARM

2. INTRODUCTION Carbamazepine is a commonly prescribed agent for local epilepsy and other non epileptic conditions such as neuropathic pain ,schizophrenia and bipolar disorder in the pediatric and adult patients. It is an anticonvulsant medication used primarily in the treatment of epilepsy and neuropathic pain. The first overdose of carbamazepine was reported in 1967,and significant toxicity occurs at levels higher than 40 mg/L(usual therapeutic levels are 4 to 12 mg/L). Common etiology for carbamazepine toxicity is coadministration of other medications.

3. Route of exposure Ingestion of the drug in large doses (drug overdose).

4. Symptoms /Clinical features • Drowsiness • Slurred speech • Ataxia • Hallucinations • Nausea and Vomiting • Tremors • Seizures • Oliguria • Blurred vision

5. Mechanism of toxicity Carbamazepine and its active metabolite causes sodium channel blockade,causing slowed impulses in the brain .< It binds preferentially to voltage-gated sodium channel in their inactive conformation, which prevents repetitive and sustained firing of action potential.

6. Etiology of toxicity Carbamazepine toxicity may result from acute overdose or chronic therapy .< Therapeutic levels are 4-12 mg/L Drug drug interaction are known to occur . Vander et al reported a case of carbamazepine toxicity that occurred after administration of oxybutynin and an increase in the dose of dantrolene. [9] The combination of these drugs elevated the level of carbamazepine, leading to toxicity.

7. Treatment and Management Prehospital care/General management: • Perform ABCD (Airway, Breathing, Circulation and Disability); • Obtain intravenous (IV) access • Place the patient on a cardiac monitor . • Administer IV fluids if the patient is hypotensive . • Administer activated charcoal if the patient has intact mental status and is able to protect the airway .

8. Contd. Emergency Department care/Specific management for Chronic poisoning: • Activated charcoal (if presents within 1 hour of ingestion).< • Gastric lavage; Perform Gastric decontamination by Diuresis/Dialysis/Haemoperfusion/Peritoneal dialysis;

9. CASE STUDY Detailed case study A 40 year male patient was referred to the emergency department of the hospital.He was admitted due to the ingestion of unknown pharmaceutical agent in an suicide attempt .THe patient has past medical history of epilepsy treated with carbamazepine and oxcarbazepine.The patient was in coma ,occasionally performing involuntary movements with his head arm and legs.

10. Route of exposure Ingestion was the route through which toxic substance entered into the body.<

11. Subjective detail • Gender - male • Age -40 yrs old • Weight -65kg • Hospital: XYZ

12. Objective detail The normal range of carbamazepine is 4-12 mg/L.(therapeutic level).< The level of carbamazepine in patient was > 20ug/ml.< The patient was subjected to hemodialysis.The patient underwent a 4 hour hemoperfusion session followed by a hemodialysis session of 4 hour .

13. Assessment The patient was diagnosed for the normal carbamazepine levels.< Hemoperfusion followed by hemodialysis was done to totally clear the high levels of carbamazepine.( 2 times the process was repeated).

14. Planning • Gastrointestinal decontamination with activated charcoal is commonly used. • Hemoperfusion followed by hemodialysis was performed in combination. • Supportive measures are to be considered. • Symptomatic treatments are to be performed as soon as the patient reaches the hospital.

15. Suggestions • Study suggests that dialysis techniques can be beneficial in a case of severe carbamazepine poisoning.<