732 P. R o b s o n
a highly characteristic pain syndrome that is particularly difficult to treat. The au-
thors note that opioids, anticonvulsants and tricyclic antidepressants are routinely
used in the treatment of this pain, but are partially effective at best. Eligible patients
continued on previously stabilised medicines, and received each test medicine for
2 weeks. During the first week of each treatment period, they were instructed cau-
tiously to self-titrate to an optimal individualised dose within a daily maximum
of 48 sprays. Both CBMEs produced moderate but highly statistically significant
improvements (Sativex:p<0.002; THC CBME:p<0.005) in BS-11 pain scores in
comparison with placebo. Sleep quality was also significantly improved by both
CBMEs. Average number of sprays/24 h was 9.2 (placebo), 7.3 (THC CBME) and 6.9
(Sativex). The authors speculated that these relatively low doses might have been
a result of the relatively short treatment periods limiting scope for self-titration, the
fact that patients remained on their pre-existing analgesics, and patients’ need to
avoid dosing if they intended to drive. Taking into account the low doses achieved
and the refractory nature of this type of neuropathic pain, the authors concluded
that CBME “may represent a significant advance in treatment.”
A small controlled study (Svendsen et al. 2003) suggests that dronabinol (syn-
thetic THC) may also be useful in MS-related pain. THC (maximum dose of
10 mg/day) was compared with placebo in a randomised, double-blind, crossover
trial with 3-week treatment periods in 24 patients with central neuropathic pain.
Spontaneous pain intensity and pain relief were both significantly improved by
THC. There was no comment on unwanted effects in this conference abstract.
Abrams et al. (2003) reported the effects of smoked cannabis in painful pe-
ripheral neuropathy secondary to human immunodeficiency virus (HIV) and/or
antiretroviral treatment. In a preliminary uncontrolled pilot study (in prepara-
tion for a planned placebo-controlled trial) “excellent” correlation was reported
between cannabis dosing and pain improvement, with 10 of 16 participants expe-
riencing a greater than 30% reduction in pain. These results provide the ethical
justification to proceed with the controlled trial.
Finally, the synthetic cannabinoid CT-3 was compared (Karst et al. 2003) with
placebo in a randomised, double-blind, crossover trial in 21 patients with chronic
neuropathic pain (cause unspecified). In 1-week treatment periods, patients re-
ceived 4 capsules (10 mg CT-3 or placebo) daily in divided doses for the first
4 days and 8 daily for the following 3 days. Pain VAS scores were significantly
improved by CT-3 in comparison with placebo (p= 0.02), although there was no
dose–response relationship. Unwanted effects (most commonly dry mouth and
tiredness) occurred more frequently following CT-3. The authors concluded that
this preliminary evaluation suggested that CT-3 was effective in reducing chronic
neuropathic pain.
2.4
Effects on Nausea and Vomiting
Many cytotoxic drugs used in the treatment of malignant disease are powerful
emetics, and the distress caused by drug-induced nausea and vomiting is the