BACKGROUND:

Olfactory loss impairs the patient’s quality of life. In individualized therapies, olfactory drug effects gain clinical importance. Molecular evidence suggests that among drugs with potential olfactory effects is tetrahydrocannabinol (THC), which is approved for several indications including neuropathic pain or analgesia in cancer patients. The present study aimed at assessing olfactory effects of THC to be expected under analgesic treatment.

METHODS:

The effects of 20 mg oral THC on olfaction were assessed in a placebo-controlled randomized cross-over study in healthy volunteers. Using an established olfactory test (Sniffin’ Sticks), olfactory thresholds, odor discrimination and odor identification were assessed in 15 subjects at baseline and 2 h after THC administration.

RESULTS:

THC impaired the subjects’ (n = 15) performance in the olfactory test. Specifically, olfactory thresholds were increased and odor discrimination performance was reduced. This resulted in a significant drop in composite TDI olfactory score by 5.5 points (from 37.7 ± 4.2 to 32.2 ± 5.6, 95% CI for differences THC versus placebo: -7.8 – -2.0, p = 0.003), which is known to be a subjectively perceptible impairment of olfactory function.

CONCLUSIONS:

Considering the comeback of THC in medical use for several pathologic conditions, present results indicate that THC based analgesics may be accompanied by subjectively noticeable reductions on olfactory acuity. In particular for patients relying on their sense of smell, this might be relevant information for personalized therapy strategies.
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PMID:

 

24802974

 

[PubMed – as supplied by publisher]