The benzodiazepines have proven of no
value in the treatment of cancer pain (68).
Their lack of benefit seems contrary to the
belief that the analgesic effect of psychotropic
drugs may stem from their anxiolytic
or sedative actions. Other antianxiety
drugs such as the barbituates and meprobamate
have been shown to have antianalgesic
properties. They are, consequently,
to be avoided. The sedative
antihistamines—diphenhydramine and
hydroxyzine—have been found useful in
the management of cancer pain and may
have an intrinsic analgesic effect (68).