title: Safety and efficacy of once-daily gastroretentive gabapentin in patients with postherpetic neuralgia aged 75 years and over.
abstract: BACKGROUND
  Treatment of postherpetic neuralgia (PHN) is more complicated in elderly patients, and multiple daily dosing, complex titration, and high incidences of adverse events can be limiting for many pharmacological treatment options.
  
  
  OBJECTIVE
  The aim of this study was to determine whether the efficacy and tolerability of once-daily gastroretentive gabapentin (G-GR) is similar between elderly patients (≥75 years) and younger patients (<75 years).
  
  
  METHODS
  Data from two phase III, placebo-controlled studies of 1,800 mg G-GR once daily with dinner in patients with PHN were integrated and analyzed by age subgroups (<75 years, n = 527; ≥75 years, n = 192). Efficacy assessments at endpoint (week 10) included baseline-adjusted change in average daily pain (ADP) and average daily sleep interference (SIS) scores, the proportion of responders (≥30 % pain reduction), and the proportion of patients feeling "Much" or "Very Much" improved on the Patient Global Impression of Change (PGIC).
  
  
  RESULTS
  Compared with placebo, patients in both age subgroups treated with G-GR (placebo/G-GR) had greater reductions in mean ADP (≥75: -21.9/-34.2 %, p = 0.0348; <75: -29.9/-38.3 %, p = 0.0079) and SIS (≥75: -1.3/-2.4, p = 0.0017; <75: -1.8/-2.7, p < 0.0001), more patients were responders (≥75: 30.4/52.0 %, p = 0.0025; <75: 45.0/54.7 %, p = 0.0265), and more felt "Much" or "Very Much" improved on the PGIC (≥75: 20.7/35.0 %, p = 0.0272; <75: 33.6/44.9 %, p = 0.0077). The most common (placebo/G-GR) adverse events (AEs) were dizziness (≥75: 3.3/12.0 %; <75: 1.8/10.4 %), nausea (≥75: 1.0/5.4 %; <75: 2.9/4.2 %), and somnolence (≥75: 0/5.0 %; <75: 3.7/4.2 %). For all patients, AEs rapidly decreased to low steady levels after 4-5 weeks of treatment. The incidence of serious AEs was low and they were reported more frequently in the placebo than in the G-GR group.
  
  
  CONCLUSIONS
  Therapy with once-daily G-GR was as effective for treating pain associated with PHN in elderly patients as it was in younger patients. G-GR was well tolerated, and the incidence of the most common AEs did not appear to be age related.
authors.affiliation: University Pain Institute, Division of Pain Medicine & Regional Anesthesiology, Department of Anesthesiology and Perioperative Medicine, Drexel University College of Medicine, 245 North 15th Street, New College Building, MS 310, Philadelphia, PA, 19102, USA, anita.gupta@drexelmed.edu.
authors.forename: Anita
authors.initials: A
authors.lastname: Gupta
authors.forename: Sean
authors.initials: S
authors.lastname: Li
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000588:Amines / Q000008:administration & dosage / Q000009:adverse effects* / Q000493:pharmacokinetics / Q000627:therapeutic use*; D000700:Analgesics / Q000008:administration & dosage / Q000009:adverse effects* / Q000493:pharmacokinetics / Q000627:therapeutic use*; D003509:Cyclohexanecarboxylic Acids / Q000008:administration & dosage / Q000009:adverse effects* / Q000493:pharmacokinetics / Q000627:therapeutic use*; D003692:Delayed-Action Preparations; D004334:Drug Administration Schedule; D005260:Female; D000077206:Gabapentin; D005753:Gastric Mucosa / Q000378:metabolism*; D006801:Humans; D008297:Male; D008875:Middle Aged; D051474:Neuralgia, Postherpetic / Q000188:drug therapy*; D014018:Tissue Distribution; D016896:Treatment Outcome; D055815:Young Adult; D005680:gamma-Aminobutyric Acid / Q000008:administration & dosage / Q000009:adverse effects* / Q000493:pharmacokinetics / Q000627:therapeutic use*
chemical_list: D000588:Amines; D000700:Analgesics; D003509:Cyclohexanecarboxylic Acids; D003692:Delayed-Action Preparations; D005680:gamma-Aminobutyric Acid; D000077206:Gabapentin