A retrospective evaluation of the use of gabapentin and pregabalin in patients with postherpetic neuralgia in usual-care settings.
BACKGROUND
Both gabapentin and pregabalin are approved for the management of postherpetic neuralgia (PHN), although dosing and pharmacokinetic differences between these medications may affect their use in actual practice.


OBJECTIVE
This study was conducted to characterize the use of gabapentin and pregabalin in the management of PHN in clinical practice, with a specific focus on the doses actually prescribed and changes in the use of other neuropathic pain-related medications after the initiation of gabapentin or pregabalin.


METHODS
The PharMetrics Patient-Centric Database was used to identify patients with PHN who were newly prescribed gabapentin or pregabalin between September 1, 2005, and March 31, 2006. The out-comes of interest were the prevalence of comorbidities, exposure to neuropathic pain-related medications (ie, the proportions of patients receiving >or=1 prescription for these medications in the 6-month periods before and after the date of the first gabapentin or pregabalin prescription), and attainment of therapeutic dose levels (gabapentin, >or=1800 mg/d; pregabalin, >or=150 mg/d).


RESULTS
The database search identified 151 patients with PHN who were newly prescribed gabapentin (57.0% female; mean [SD] age, 55.8 [11.3] years) and 100 patients who were newly prescribed pregabalin (62.0% female; mean age, 52.8 [9.4] years). The prevalence of comorbidities did not differ significantly between recipients of prescriptions for gabapentin or pregabalin, with the exception of hyperlipidemia, which was more prevalent in those prescribed gabapentin (33.8% vs 22.0%, respectively; P = 0.044), and depression, which was more prevalent in those prescribed pregabalin (12.0% vs 4.6%, respectively; P = 0.031). In the pretreatment period, those who were prescribed pregabalin had significantly greater use of long-acting opioids (P = 0.005), anticonvulsants (P < 0.001), selective norepinephrine reuptake inhibitors (P < 0.001), and the lidocaine 5% patch (P = 0.005) compared with those prescribed gabapentin. Use of any opioid increased from pretreatment to follow-up in those prescribed gabapentin, significantly so in those who received >or=2 opioid prescriptions (P = 0.016). Use of any opioid decreased significantly from pre-treatment to follow-up in those prescribed pregabalin (P = 0.005), particularly in those who received >or=2 opioid prescriptions (P = 0.004). Tramadol use decreased significantly in those prescribed gabapentin (P = 0.045), and anticonvulsant use decreased significantly in those prescribed pregabalin (P = 0.004). Among patients prescribed gabapentin or pregabalin who received 1 prescription, 2 consecutive prescriptions, and >or=3 consecutive prescriptions, a greater proportion of those prescribed pregabalin attained therapeutic dose levels by their first, second, and third consecutive prescriptions compared with those prescribed gabapentin (69.0% vs 3.5%, respectively [P < 0.001]; 71.4% vs 21.7% [P < 0.001]; and 89.3% vs 46.2% [P < 0.001], respectively).


CONCLUSIONS
In these patients with PHN in the usual-care setting, opioid use increased after the initiation of gabapentin and decreased after the initiation of pregabalin. Few of those prescribed gabapentin received a prescription for a therapeutic dose, whereas a greater proportion of patients who were prescribed pregabalin received a prescription for a therapeutic dose.
Gore
Mugdha
M
Avalon Health Solutions, inc., Philadelphia, Pennsylvania 19102, USA. mgore@avalonhealthsolutions.com
Sadosky
Alesia
A
Tai
Kei-Sing
KS
Stacey
Brett
B
D018759:Adrenergic Uptake Inhibitors / Q000627:therapeutic use; D000328:Adult; D000368:Aged; D000588:Amines / Q000008:administration & dosage / Q000627:therapeutic use*; D000700:Analgesics / Q000008:administration & dosage / Q000627:therapeutic use*; D000701:Analgesics, Opioid / Q000627:therapeutic use; D000927:Anticonvulsants / Q000627:therapeutic use; D003509:Cyclohexanecarboxylic Acids / Q000008:administration & dosage / Q000627:therapeutic use*; D019992:Databases as Topic / Q000706:statistics & numerical data; D004359:Drug Therapy, Combination; D005260:Female; D000077206:Gabapentin; D006801:Humans; D008012:Lidocaine / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D051474:Neuralgia, Postherpetic / Q000188:drug therapy* / Q000453:epidemiology; D010147:Pain Measurement; D010818:Practice Patterns, Physicians' / Q000706:statistics & numerical data*; D000069583:Pregabalin; D012189:Retrospective Studies; D014147:Tramadol / Q000627:therapeutic use; D016896:Treatment Outcome; D014481:United States / Q000453:epidemiology; D005680:gamma-Aminobutyric Acid / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000627:therapeutic use
D018759:Adrenergic Uptake Inhibitors; D000588:Amines; D000700:Analgesics; D000701:Analgesics, Opioid; D000927:Anticonvulsants; D003509:Cyclohexanecarboxylic Acids; D014147:Tramadol; D000069583:Pregabalin; D005680:gamma-Aminobutyric Acid; D000077206:Gabapentin; D008012:Lidocaine