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Query: UMLS:C0030193 (pain)
 261,466 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Venlafaxine hydrochloride (Effexor) is a structurally novel antidepressant that inhibits reuptake of 5-hydroxytryptamine and noradrenaline, but unlike the older antidepressants, has few side-effects. The objective of this study was to determine whether venlafaxine relieves thermal hyperalgesia in rats with neuropathic pain due to chronic constriction injury (CCI) of the sciatic nerve. Paw withdrawal latency (PWL) to heat was tested for each hind paw. A painful neuropathy was induced in 24 male Sprague-Dawley rats (Group 1) as described by Bennett and Xie. Rats randomly received either oral venlafaxine (22 mg/kg) or placebo via gavage feeding beginning the day after surgery. Postoperative PWL testing began 3 days after CCI (Time 0). A second group of 12 rats (Group 2) was used to confirm that venlafaxine reverses hyperalgesia in rats with a fully developed neuropathic lesion. These animals began to receive oral venlafaxine (22 mg/kg) starting on the third postoperative day, after the presence of thermal hyperalgesia was verified through PWL testing. Testing was continued for 5 days, during venlafaxine administration. A third group of 12 rats (Group 3) had activity measured before and after treatment with venlafaxine (22 mg/kg). Rats in the placebo group developed thermal hyperalgesia while those that received venlafaxine did not. Venlafaxine also appeared to have a mild non-specific analgesic effect that increased PWL in the sham limb. In Group 2, thermal hyperalgesia was present on day 3, but following treatment with venlafaxine, thermal hyperalgesia resolved. Activity measurements confirmed that venlafaxine was not sedating in this rat model.
Pain 1996 Nov
PMID:Venlafaxine hydrochloride (Effexor) relieves thermal hyperalgesia in rats with an experimental mononeuropathy. 925 10

Venlafaxine blocks the specific monoamine transporters and is devoid of significant action on muscarinic cholinergic receptors. To our knowledge, no cases of glaucoma have been reported so far. Because pain perception involves both serotonergic and noradrenergic mechanisms, venlafaxine also may be useful in neuropathic pain therapy. We report on two patients with narrow angle glaucoma affected by chronic pain. When venlafaxine treatment was begun, their ocular pressure was steadily around 17-18 mmHg. Venlafaxine was chosen (daily dose 75 mg) because this drug is claimed not to bind on muscarinic cholinergic receptors. However, 4 days later the ocular pressure of the first patient increased to 22 mmHg, which led to suspension of the drug. The ocular pressure of the second patient was 18.5 mmHg after a week, 21 mmHg after 2 weeks, and 23 mmHg after 16 days. One week after suspension, ocular pressure of the patients was 17 and 18 mmHg, respectively. Possible explanations of this ocular effect are offered: pharmacokinetic interference on the drugs used in glaucoma treatment, in vivo action on the muscarinic receptor, indirect effect via dopaminergic receptors, or direct effect on the ocular sympathetic postganglionic neurones. In any case, from a clinical viewpoint, caution should be used when giving venlafaxine to patients with narrow-angle glaucoma, and ocular pressure must be monitored.
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PMID:Increased ocular pressure in two patients with narrow angle glaucoma treated with venlafaxine. 957 1

Venlafaxine and tramadol are relatively new compounds indicated for the treatment of depression and pain, respectively. These agents share a number of molecular and pharmacological features that may allow for broader and overlapping therapeutic indications for both drugs. Additionally, certain patient populations with coexisting depression and pain syndromes could potentially be treated with a single agent.
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PMID:Venlafaxine-tramadol similarities. 988 25

The antinociceptive effects of the novel phentylethylamine antidepressant drug venlafaxine and its interaction with various opioid, noradrenaline and serotonin receptor subtypes were evaluated. When mice were tested with a hotplate analgesia meter, venlafaxine induced a dose-dependent antinociceptive effect following i.p. administration with an ED50 of 46.7 mg/kg (20.5; 146.5; 95% CL). Opioid, adrenergic and serotoninergic receptor antagonists were tested for their ability to block venlafaxine antinociception. Venlafaxine-induced antinociception was significantly inhibited by naloxone, nor-BNI and naltrindole but not by beta-FNA or naloxonazine, implying involvement of kappa1- and delta-opioid mechanisms. When adrenergic and serotoninergic antagonists were used, yohimbine (P < 0.005) but not phentolamine or metergoline, decreased antinociception elicited by venlafaxine, implying a clear alpha2- and a minor alpha1-adrenergic mechanism of antinociception. When venlafaxine was administered together with various agonists of the opioid and alpha2- receptor subtypes, it significantly potentiated antinociception mediated by kappa1- kappa3- and delta-opioid receptor subtypes. The alpha2-adrenergic agonist clonidine significantly potentiated venlafaxine-mediated antinociception. Summing up these results, we conclude that the antinociceptive effect of venlafaxine is mainly influenced by the kappa- and delta-opioid receptor subtypes combined with the alpha2-adrenergic receptor. These results suggest a potential use of venlafaxine in the management of some pain syndromes. However, further research is needed in order to establish both the exact clinical indications and the effective doses of venlafaxine when prescribed for pain.
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PMID:The antinociceptive effect of venlafaxine in mice is mediated through opioid and adrenergic mechanisms. 1050 22

Chronic pain is both difficult for patients to tolerate and for clinicians to treat effectively. It differs from other types of pain in etiology and impact, which in turn affects the duration and modalities of treatment options. Forty years of research have confirmed the efficacy of antidepressant agents in the management of chronic pain, yet these agents are used inadequately. A significant amount of evidence supports the use of the traditional tricyclic antidepressants (TCAs) in the management of chronic pain, but because of their acute synaptic effects on multiple, nontherapeutic receptor systems, they are associated with numerous undesirable side effects. The newer selective serotonin reuptake inhibitors (SSRIs) have, comparatively, only serotonin-receptor-mediated side effects. These agents have not been thoroughly studied in the treatment of chronic pain. Moreover, because SSRIs impact reuptake of only one monoamine system, it is plausible that they may be less efficacious than the TCAs in treating chronic pain. Venlafaxine, the first agent in the new class of serotonin (5-HT)-norepinephrine (NE) reuptake inhibitors, is unique because it inhibits reuptake of both 5-HT and NE (and to a lesser extent dopamine), as do some of the TCAs; however, it accomplishes this without affecting other nontherapeutic receptors. Venlafaxine is at least as effective as the TCAs, but is more tolerable, because it lacks the receptor-mediated side effects common to the TCAs. The unique characteristics of venlafaxine, including minimal cytochrome P-450 drug interaction, may make it a particularly useful antidepressant in the adjunctive treatment of chronic pain.
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PMID:The management challenges of chronic pain: the role of antidepressants. 1131 71

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.
Eur J Pain 2002
PMID:Venlafaxine in neuropathic pain following treatment of breast cancer. 1188 24

Before 1980s, tricyclics (TCAs) were considered, between antidepressants, the standard in the treatment of different kinds of neuropathic pain, for their action on noradrenergic and serotoninergic pathways, thought the high incidence of side effects. In 1980s a new class of antidepressants has been introduced, the selective serotonin reuptake inhibitors (SSRI). We reviewed some publications, including trials comparing SSRIs with TCAs in pain management. The available literature did not show an effective superiority of the former on the latter, though improved side-effect profile. Recently new antidepressants were introduced in the clinical use, with a significant reduction in side effects and equivalent efficacy on mood disorders. These new drugs may be classified in three categories: Serotonin and Noradrenergic Reuptake Inhibitors (SNaRI), like venlafaxine and nefazodone; Noradrenergic and Specific Serotoninergic Antidepressants (NaSSA), like mirtazapine, and Noradrenaline Reuptake Inhibitors (NaRI), like reboxetine. In this review we present the available publications of their application in the treatment of neuropathic pain. Venlafaxine (SNaRI), the most investigated of these new drugs, was shown to be effective in the treatment of different kinds of pain, with side-effects profile significantly better than TCAs. The other new antidepressants have been less extensively studied, thus only anecdotal therapeutic results and experimental works have been found and reported. Existing data are surely insufficient to conclude which of these new classes of drugs has the best clinical profile and can be more effective in the treatment of neuropathic pain, but the lower incidence of side effects should be considered. Further evidence-based research in the safety and efficacy of these promising agents in pain relief, is warranted.
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PMID:New antidepressants in the treatment of neuropathic pain. A review. 1198 19

Venlafaxine, a new antidepressant with fewer side effects, could be of interest to reduce neuropathic pain following antineoplasic drug treatment. In the present study, we demonstrated that venlafaxine inhibits hyperalgesia in a new rat model of neuropathy induced by the antineoplasic drug vincristine, and exerts its effect preferentially via supraspinal and spinal mechanisms.
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PMID:Evidence for an antihyperalgesic effect of venlafaxine in vincristine-induced neuropathy in rat. 1286 65

Major depressive disorder is frequently undiagnosed and untreated in older patients. Grief, pain, sleep issues, concurrent medications, altered physiology, and the presence of comorbid medical and psychiatric conditions can complicate the management of depression in older patients. Remission should be the goal of therapy in treating depression in the elderly, just as it is in younger patients, to maximize the impact of treatment on quality of life. Managing depression in older patients can be done effectively with the antidepressant therapies currently available, including selective serotonin reuptake inhibitors (SSRIs), venlafaxine, and mirtazapine. Comorbid medical conditions, which are common among older patients, can have a significant impact on depression and vice versa. Antidepressant therapy with SSRIs has demonstrated efficacy and tolerability in patients at high risk for cardiovascular events and stroke and in those with vascular dementia or Alzheimer's disease. Care should be taken to choose antidepressants with no or minimal effects on glucose levels in patients with diabetes. In addition, venlafaxine has demonstrated beneficial effects on the relief of the pain of diabetic neuropathy. Venlafaxine, mirtrazapine, and the SSRIs have demonstrated efficacy and tolerability in older patients, while tricyclic antidepressants have also demonstrated efficacy; however, tolerability can be a problem. Depression is not a natural part of the aging process, as some still believe. The review of current data indicates that the goal of management can and should be full remission. Further, the use of newer agents is safe and effective in this population, as long as one considers the pharmacokinetics and pharmacodynamic properties and inherent biological differences in the elderly population when selecting appropriate therapy.
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PMID:Special issues in the management of depression in older patients. 1514 35

Postmastectomy pain syndrome (PMPS) is a neuropathic pain syndrome that may develop following breast surgery. Venlafaxine has been shown to be efficacious in the management of PMPS. The preemptive administration of venlafaxine has been shown to be efficacious in reducing the incidence of neuropathic pain in the rat model. We examined the efficacy of administering either venlafaxine or placebo for two weeks starting the night before surgery to 100 patients scheduled for either partial or radical mastectomy with axillary dissection. Patients were administered PCA morphine for the first 24 hours following surgery and then acetaminophen/oxycodone tablets. Pain scores were recorded at rest and movement on day 1, at 1 month, and at 6 months after surgery. At 6 months postoperatively, the presence of pain in the chest, arm, and axilla; edema; decreased sensation in the operative area; and phantom breast pain were recorded. There was no difference in postoperative opioid use. Pain scores with movement were lower in the venlafaxine group at 6 months. Pain scores at all other time intervals were similar. There was a significant decrease in the incidence of chest wall pain (55% vs. 19%, P = 0.0002), arm pain (45% vs. 17%, P = 0.003), and axilla pain (51% vs. 19%, P = 0.0009) between the control group and the venlafaxine group, respectively. No significant differences were noted between the two groups with regard to edema, phantom pain, or sensory changes. We conclude that the perioperative administration of venlafaxine beginning the night prior to surgery significantly reduces the incidence of PMPS following breast cancer surgery.
J Pain Symptom Manage 2004 Feb
PMID:Evaluation of efficacy of the perioperative administration of venlafaxine XR in the prevention of postmastectomy pain syndrome. 1942 87


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