Analgesia is one of the pharmacological actions of cannabinoids, which are often used to treat chronic pain.
Dronabinol is a safe long-term treatment approch for the
treatment of neuropathic pain.
Analgesia is one of the pharmacological actions of
cannabinoids, which are often used to treat chronic pain. Cannabinoids are the
central nervous system (CNS) acting drugs which mainly works on CB1 and CB2
receptors located in the CNS and other tissues like lungs, liver and immune
cells. Several studies have investigated the long-term effects of the
cannabis-based medicine and these studies lasting from 38 weeks to 3.5 years
showed no significant safety concerns and reported good tolerability.
Nevertheless, the medical use of cannabis was controversially discussed.
Dronabinol, a synthetic form of
tetrahydrocannabinol (THC) is approved by the Food and Drug Association (FDA).
Svendsen et al showed that dronabinol has a clinically relevant
analgesic effect with good tolerability. Another study by Rog et al
showed significant results and provided evidence for the safe and efficient
reduction of pain and sleep disturbance after four weeks treatment with
cannabis-based medicine containing dronabinol and CBD. On the other hand,
Langford et al failed to show the efficacy of an oromucosal
dronabinol/CBD spray in patients treated for 33 weeks, whereas the occurrence
of adverse events (AEs) was similar for verum and placebo. Therefore, to
address these safety issues, Sebastian Schimrigk et al performed this
clinical trial to demonstrate the efficacy and safety of dronabinol in the
treatment of patients with multiple sclerosis (MS) and chronic neuropathic pain
(CNP).
Rationale behind the research:
The number of clinical trials with cannabis-based therapeutics have been performed, but the medical use of cannabis was still controversially discussed. Therefore, the present study addresses these open safety issues, and aimed to show efficacy and long-term safety of dronabinol in the treatment of patients with MS and CNP.
Objective:
To
demonstrate the positive benefit-risk ratio of dronabinol against the
neuropathic pain.
Study
outcome measures:
Time period: Baseline, 16 weeks, 32 weeks and 96 weeks.
Study Outcomes
There was not statistically significant (p= 0.6760) difference between the mean change of pain intensity from baseline to mean of weeks 1–16 compared between dronabinol (1.92 ± 2.01; 30%) and placebo (1.81 ± 1.94; 27%). (Figure 1).
The QoL assessment (SF-36) showed a definite improvement during the double-blind period from baseline until end of treatment in both groups (physical component summary: verum: –3.50, placebo: –3.18; mental component summary: verum: –2.69, placebo: –0.60) without significant difference.
Approx. 92.9% of patients experienced at least one AE. Patients experiencing AEs were higher in the dronabinol group than in the placebo group. The proportion of patients experiencing SAEs was low.
After all the three time periods the global tolerability mostly was very good (double-blind period: verum: 84.5%; placebo: 95.6%; open-label period: 85.2%; follow-up period: 93%).
No clinically relevant changes in the vital signs such as blood pressure, heart rate, and weight were observed. Both blood hematology and biochemistry analysis did not reveal any clinically relevant differences or trends. The presence of severe cardiac diseases could be ruled out clinically and by ECG for 90% of patients at the end of treatment.
For most patients, no withdrawal reactions were reported after cessation of the study medication.
Mild signs of drug dependency were documented only for 1 patient. No patient showed any sign of drug abuse.
This clinical trial demonstrated a
significant decrease of mean pain intensities during 16-weeks dronabinol and
placebo treatment. These results revealed that dronabinol is a safe long-term
treatment option for neuropathic pain. The similar number of side effects have
occurred in patients with MS and CNP in comparison to standard treatment. A
previous clinical trial performed by Svendsen et al with dronabinol showed its efficacy superiority over placebo.
Besides the analgesic effect of dronabinol, the other therapeutic effects such
as sedative, spasmolytic, anti-inflammatory and anxiolytic may contribute to
improving QoL of NP patients, which is the overall therapeutic goal. Patients’
QoL may also be affected by side effects, which are in general quite common for
centrally acting substances. In this study, the proportion of patients with ARs
was highest in the beginning and declined during the dronabinol treatment. Most
AEs and ARs were non-serious and of mild to moderate. In this trial, the most
frequent ARs belonged to “nervous system disorders” followed by “general
disorders and administration site conditions”. The assessment of dronabinol’s
potential to induce withdrawal symptoms, dependency, abuse and tolerance during
long-term follow-up of our trial revealed no negative hints. Despite the long
duration of dronabinol intake, only 10 patients showed transient withdrawal
symptoms.
In conclusion, the dronabinol has
long-lasting therapeutic potential, the good tolerability and favorable safety
profile of dronabinol especially regarding drug abuse and dependency makes it a
preffered choice in the treatment of neuropatihc pain.
This trial determined the long-lasting therapeutic effect, the good
tolerability and favorable safety profile of dronabinol especially concerning
drug abuse and dependency.
Eur Neurol 2017;78:320-329.
Dronabinol Is a Safe Long-Term Treatment Option for Neuropathic Pain Patients
Schimrigk S et al.
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