On the antinociceptive effect of fluoxetine,
a selective serotonin reuptake inhibitor

Singh VP, Jain NK, Kulkarni SK.
Pharmacology Division,
University Institute of Pharmaceutical Sciences,
Panjab University, 160 014,
Chandigarh, India.
Brain Res 2001 Oct 12;915(2):218-26


Antidepressant drugs are reported to be used as co-analgesics in clinical management of migraine and neuropathic pain. The mechanism through which they alleviate pain remains unknown. The present study explores the possible mechanism of a selective serotonin reuptake inhibitor (SSRI) fluoxetine-induced antinociception in animals. Acetic acid-induced writhing, hot plate and tail-flick test were used to assess fluoxetine-induced antinociception. Fluoxetine (5-20 mg kg(-1), i.p.) produced a significant and dose-dependent antinociceptive effect against acetic acid-induced writhing in mice. Fluoxetine (20 mg kg(-1)) also exhibited antinociceptive effect in tail flick as well as hot plate assays. Further, i.c.v. administration of fluoxetine showed significant antinociception against writhing test in rats. However, fluoxetine (1 &mgr;g/10 &mgr;l/rat, i.c.v.) did not exhibit any antinociceptive effect in serotonin-depleted animals. Further, pindolol (10 mg kg(-1), i.p.) enhanced fluoxetine-induced antinociceptive effect. The antinociceptive effect of fluoxetine was sensitive to blockade by naloxone (5 mg kg(-1), i.p.) and naltrexone (5 mg kg(-1), i.p.). These data suggest that fluoxetine-induced antinociception involves both central opioid and the serotoninergic pathways.
Analgesia and pain-relief
Opiates as antidepressants
Opioids, mood and cognition
Is morphine an antidepressant?
Depression, opioids and the HPA
Endomorphins as antidepressants?
Opiates for treatment-resistant depression
Opioids, depression and learned helplessness
Antidepressive response and depression subtypes
Use of oxycodone and oxymorphone to treat major depression
Kappa agonists, antagonists and partial agonists for mood disorders

and further reading

Future Opioids
BLTC Research
Utopian Surgery?
The Abolitionist Project
The Hedonistic Imperative
The Reproductive Revolution
Critique of Huxley's Brave New World

The Good Drug Guide
The Good Drug Guide

The Responsible Parent's Guide
To Healthy Mood Boosters For All The Family