Nabilone is a new orally active
cannabinoid for the treatment of severe gastrointestinal toxicity associated with
cancer chemotherapy. The pharmacological profile of
nabilone suggests that it acts primarily by preventing
emesis controlled by the medulla oblongata, although its secondary mild
anxiolytic activity may contribute to the overall efficacy.
Nabilone 2mg twice daily starting 12 hours prior to, and continued for the duration of,
chemotherapy produces significant reduction in the severity and duration of
nausea and the frequency of
vomiting in about 50 to 70% of patients with severe symptoms refractory to conventional
therapy.
Nabilone has proven to be more effective in controlling symptoms and preferred by more patients than
prochlorperazine 10mg 2 to 4 times daily in a limited number of studies, despite a higher incidence of side effects. Comparative trials against other new
antiemetic agents, such as high dose
metoclopramide, and use of
nabilone in combination with other
antiemetics remain to be undertaken. The incidence of side effects is high with
nabilone; drowsiness,
dizziness and/or
vertigo occur in 60 to 70% of patients, but rarely lead to
drug withdrawal, although more troublesome effects, such as
postural hypotension,
ataxia, vision disturbance and
toxic psychoses, may cause discontinuation of
therapy. Thus,
nabilone offers an effective alternative to the treatment options available in a difficult therapeutic area - those patients with severe gastrointestinal side effects from
cancer chemotherapy who are refractory to conventional
therapy.