title: Venlafaxine in neuropathic pain following treatment of breast cancer.
abstract: Amitriptyline effectively relieves neuropathic pain following treatment of breast cancer. However, adverse effects are a major problem. Venlafaxine has no anticholinergic effects and could have a better compliance. The aim of the study was to evaluate the effectiveness of venlafaxine in neuropathic pain. The study was a randomized, double-blind, crossover comparison of venlafaxine and inactive placebo. The study lasted 10 weeks. The number of tablets (18.75 mg) taken daily was increased by one at a 1 week interval. Pain intensity and pain relief were registered daily by a diary and by a questionnaire and a computer program (Painscreen) on each visit. Adverse effects were evaluated with the diaries and a 10-item list on each visit. Also, anxiety and depression were measured on each visit. Venous blood samples were collected before the treatment and at 4 weeks for the determination of the serum levels of venlafaxine and its three metabolites. Thirteen patients were analysed. The average daily pain intensity as reported in the diary (primary outcome) was not significantly reduced by venlafaxine compared with placebo. However, the average pain relief (diary) and the maximum pain intensity (retrospective assessment by the computer program) were significantly lower with venlafaxine compared with placebo. Anxiety and depression were not affected. Adverse effects did not show significant differences between treatments. The two poor responders had low venlafaxine concentrations whereas the two slow hydroxylizers had high venlafaxine concentrations and excellent pain relief. Thus, higher doses could be used in order to improve pain relief.
authors.affiliation: Pain Clinic, Department of Anaesthesia and Intensive Care Medicine, Helsinki University Central Hospital, FIN-00029 HUS, Helsinki, Finland.
authors.forename: Tiina
authors.initials: T
authors.lastname: Tasmuth
authors.forename: Brita
authors.initials: B
authors.lastname: Härtel
authors.forename: Eija
authors.initials: E
authors.lastname: Kalso
mesh_terms: D000700:Analgesics / Q000097:blood / Q000627:therapeutic use*; D001943:Breast Neoplasms / Q000150:complications* / Q000628:therapy; D018592:Cross-Over Studies; D003511:Cyclohexanols / Q000097:blood / Q000627:therapeutic use*; D000069468:Desvenlafaxine Succinate; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D008408:Mastectomy / Q000009:adverse effects; D009437:Neuralgia / Q000188:drug therapy* / Q000523:psychology; D010147:Pain Measurement / Q000187:drug effects; D010523:Peripheral Nervous System Diseases / Q000188:drug therapy* / Q000523:psychology; D011183:Postoperative Complications / Q000188:drug therapy* / Q000209:etiology / Q000503:physiopathology; D016896:Treatment Outcome; D000069470:Venlafaxine Hydrochloride
chemical_list: D000700:Analgesics; D003511:Cyclohexanols; D000069470:Venlafaxine Hydrochloride; D000069468:Desvenlafaxine Succinate