Repeated tender point injections of granisetron alleviate chronic myofascial pain - a randomized, controlled, double-blinded trial

Abstract

BackgroundSerotonin (5-HT) mediates pain by peripheral 5-HT3-receptors. Results from a few studies indicate that intramuscular injections of 5-HT3-antagonists may reduce musculoskeletal pain. The aim of this study was to investigate if repeated intramuscular tender-point injections of the 5-HT3-antagonist granisetron alleviate pain in patients with myofascial temporomandibular disorders (M-TMD).MethodsThis prospective, randomized, controlled, double blind, parallel-arm trial (RCT) was carried out during at two centers in Stockholm, Sweden. The randomization was performed by a researcher who did not participate in data collection with an internet-based application (www.randomization.com). 40 patients with a diagnose of M-TMD according to the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) were randomized to receive repeated injections, one week apart, with either granisetron (GRA; 3 mg) or isotonic saline as control (CTR).ResultsThe median weekly pain intensities decreased significantly at all follow-ups (1-, 2-, 6-months) in the GRA-group (Friedman test; P < 0.05), but not in the CTR-group (Friedman-test; P > 0.075). The numbers needed to treat (NNT) were 4 at the 1- and 6-month follow-ups, and 3.3 at the 2-month follow-up in favor of granisetron.ConclusionsRepeated intramuscular tender-point injections with granisetron provide a new pharmacological treatment possibility for myofascial pain patients with repeated intramuscular tender-point injections with the serotonin type 3 antagonist granisetron. It showed a clinically relevant pain reducing effect in the temporomandibular region, both in a short- and long-term aspect.Trial registrationEuropean Clinical Trials Database 2005-006042-41 as well as at Clinical Trials NCT02230371.

Influence of Polymorphisms in the HTR3A and HTR3B Genes on Experimental Pain and the Effect of the 5-HT3 Antagonist Granisetron

“…Granisetron has a long half-life since it is metabolized in the liver. A total of 0.5 mL of granisetron (Gra; Kytril ® , 1 mg/mL, Roche, Stockholm, Sweden) and placebo (isotonic saline, 9 mg/mL) was used as in previous studies from this group [24, 41, 42]. The same infusion rate as for the HS injections (0.02 mL/s) was used, i.e.…”

“…Clinical studies have also shown that 5-HT 3 antagonists are effective analgesics for various pain conditions, such as TMD myalgia, localized trapezius myalgia and fibromyalgia [21–24]. However, in most clinical trials a great proportion of the patients, regardless of diagnosis, do not respond to 5-HT 3 antagonists.…”

Placebo and nocebo response magnitude on temporomandibular disorder‐related pain: A systematic review and meta‐analysis

“…Risk of bias was very heterogeneous among studies. Using Cochrane Collaboration's tool, nine studies were classified as low risk of bias, 13 as unclear and 20 as high risk of bias . The higher risk of bias was reporting bias.…”

Blockade of 5‐HT3 receptors with granisetron does not affect trigeminothalamic nociceptive transmission in rats: Implication for migraine

“…For example, there are clinical data demonstrating that setrons exert analgesic effect on both extracranial pain syndromes and various orofacial pain . Setrons have been reported to display analgesic, anti‐allodynic and anti‐hyperalgesic activities in animal models not only of non‐trigeminal, but also of trigeminal nociception .…”

“…For example, there are clinical data demonstrating that setrons exert analgesic effect on both extracranial pain syndromes 5,6 and various orofacial pain. 7,8 Setrons have been reported to display analgesic, anti-allodynic and anti-hyperalgesic activities in animal models not only of non-trigeminal, 9,10 but also of trigeminal nociception. [11][12][13] The latter is of particular interest since the trigeminal Summary One way to expand the existing range of anti-migraine drugs seems to be the search for pharmacological agents with anti-cephalalgic properties among medicines approved for clinical indications other than migraine.…”