Compliance and persistence of antidepressants versus anticonvulsants in patients with neuropathic pain during the first year of therapy.
BACKGROUND
Neuropathic pain (NP) is a chronic condition that has human, social, and economic consequences. A variety of agents can be used for treatment; however, antidepressants and anticonvulsants are the 2 classes most widely studied and represent first-line agents in the management of NP. Little information is known about the adherence patterns of these medications during the first year of therapy in patients with NP.


OBJECTIVE
To examine the compliance and persistence of antidepressants versus anticonvulsants in patients with NP during the first year of therapy.


METHODS
Using electronic medical and pharmacy data for the Kaiser Permanente Southern California region, the adherence patterns for patients with a NP diagnosis prescribed an antidepressant or an anticonvulsant were studied. Compliance and persistence were measured using the medication possession ratio and the Refill-Sequence model, respectively.


RESULTS
The study included 1817 patients with NP diagnosis taking either an antidepressant or an anticonvulsant. Within the antidepressant group, 42.9% were considered compliant, compared with 43.7% in the anticonvulsant group. Subanalysis of the 2 cohorts revealed that patients on venlafaxine were the most compliant (69.4%) compared with patients taking gabapentin (44.4%) and tricyclic antidepressants (41.8%) (P<0.01). Only 21.2% of patients in the antidepressant group and 21.4% in the anticonvulsant group were considered persistent with their medication refills.


CONCLUSIONS
Compliance and persistence rates were similar for patients with NP diagnosis taking antidepressants and anticonvulsants. Higher compliance was observed among patients taking venlafaxine; however, this population did have a small sample size.
Pharmacy Operations Office, Kaiser Permanente, Los Angeles Medical Center, Los Angeles, CA 90027, USA. derenik.x.gharibian@kp.org
Derenik
D
Gharibian
Jennifer K
JK
Polzin
Jay P
JP
Rho
D000927:Anticonvulsants / Q000627:therapeutic use*; D000928:Antidepressive Agents / Q000627:therapeutic use*; D002140:California / Q000453:epidemiology; D011307:Drug Prescriptions / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009437:Neuralgia / Q000188:drug therapy* / Q000453:epidemiology*; D015995:Prevalence; D012189:Retrospective Studies; D016896:Treatment Outcome; D016903:Drug Monitoring
D000927:Anticonvulsants; D000928:Antidepressive Agents