Variability of phenytoin, carbamazepine and valproate concentrations in a clinic population.
The Comprehensive Epilepsy Program of Minnesota database was searched for patients who had no dose change of carbamazepine (CBZ), phenytoin (PHT) or valproate (VPA) for 3 consecutive visits. Data from 860 patients were available. The coefficient of variation (CV) was calculated from 3 or more visits without dose change. For CBZ, 290 CV values from 206 individuals were available; the mode CV was 23.3%. For PHT 293 CVs were collected from 192 individuals; the mode CV was 25.2%. For VPA 244 CVs was 181 persons; the mode CV was 27.1%. If one uses the standard of a CV of less than 20% representing compliance with PHT, and a CV of less than 25% for CBZ and VPA, it appears that even in a specialty clinic, compliance with medication is a significant problem.
Leppik
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Comprehensive Epilepsy Program of Minnesota, Minneapolis 55414.
D002220:Carbamazepine / Q000008:administration & dosage / Q000097:blood* / Q000627:therapeutic use; D004827:Epilepsy / Q000097:blood / Q000188:drug therapy* / Q000523:psychology; D005260:Female; D006801:Humans; D008297:Male; D008910:Minnesota; D010044:Outpatient Clinics, Hospital; D010349:Patient Compliance; D010672:Phenytoin / Q000008:administration & dosage / Q000097:blood* / Q000627:therapeutic use; D014635:Valproic Acid / Q000008:administration & dosage / Q000097:blood* / Q000627:therapeutic use
D002220:Carbamazepine; D014635:Valproic Acid; D010672:Phenytoin