Anticonvulsants - Carbamazepines

1. Rational Drug Selection

1.1. diethylpropion - one of the safest nonadrenergic appetite suppressants. may be used w/ pt with moderate htn

2. Cost

2.1. $15-30

3. Monitoring

3.1. Watch TSK and blood levels

4. Patient Education

4.1. no grapefruit juice,

4.2. report any symptom of skin lesions, bruising, fever , or sore throat.

4.3. administration with food will increase absorption

4.4. can be sedating, exercise caution when needing to be mentally alert

5. Comments

6. Carbamazepine (Tegretol), oxcarbazepine (Trileptal), eslicarbazepine (Aptiom)

7. Pharmacokinetics

7.1. A&D: absorb thru stomach, suspension being absorbed quicker than tablet form. Drug is highly lipophilic, resulting in high body tissue binding. 67% protein bound 40% active metabolites. eslicarbazepine is highly bioavailable after oral admin

7.2. M&E: metabolized in liver - unique ability to induce its own metabolism (autoinduction). induces metabolism of many CYP450 enzymes. Excret urine / feces

8. Precautions

8.1. use with caution in pt with increase intraocular pressure. and with those with cardiac, renal, or hepatic impairment

8.2. Cross sensitivity with TCAs,

9. Contraindications

9.1. CI - bone marrow suppression, MAOI use, glaucoma, any hematologic reaction to drugs, cardiac renal hepatic impairment – lots of contraindications

10. Black box / Preg Category

10.1. carbamazepine Cat D, teratogenic defects have occurred black box warning of SJS and toxic epidermal necrolysis (esp asian) - oxcarbazepine is cat C

11. ADRS

11.1. carbamazepine has black box warning for development of SJS and toxic epidermal necrolysis in pts of chinese ethnicity. Can alos cause blood dyscrasias. depresses bone marrow and can lead to leukopenia, thrombocytopenia, aplastic anemia

11.2. SE from oxcarbazepine is dizziness, diplopia, somnolence, fatigue, nausea, vomiting, ataxia, abd pain, tremor, dyspepsia.

12. Drug Interactions

12.1. concurrent admi of propoxyphene, hydantoins, cimetidine, some antibiotics, can increase plasma level of drug to toxic levals

12.2. beta blocked

13. Clinical Use

13.1. carbamazepine - partial complex siezure disorder, trigemical neuralgia, bipolar disorder, aggresive behavioir

13.2. oxcarbazepine - monotherapy for partial seizures

14. Pharmacodynamics

14.1. thought to affect the sodium channel, slowing influx of sodium in the cortical neurons and close the spread of abnormal activity