3.4.4 Neuroleptic Agents
Methotrimeprazine is a phenothiazine that has analgesic properties.
Intramuscular doses of 15 mg methotrimeprazine and 10 mg of morphine are
equianalgesic (Lasagna et al., 1961). This phenothiazine analgesic lacks
opioid-inhibitory effects on gut motility and probably produces analgesia
through a-adrenergic blockade (Beaver, Wallenstein, Hcude, et al., 1966). In
patients who are opioid tolerant or who are experiencing dose-limiting opioid
side effects, especially intractable constipation, it is an alternative
analgesic approach. It also has antiemetic and anxiolytic effects.
Methotrimeprazine can produce sedation and hypotension and should be given
cautiously. Although it is approved only for intramuscular administration,
clinicians have experience with oraz and slow intravenous infusion to manage
delirium, restlessness, and agitation in patients near death. Other
phenothiazines have not been demonstrated to have analgesic properties
(Maltbie, Cavenar, Sullivan, et al., 1979).
Drugs and routes of administration not recommended for treatment of cancer pain