The effects of pentazocine, a kappa agonist, in patients with mania.

Past evidence suggests that activation of kappa opiate receptors may lower mood. However, kappa agonists may also induce psychotomimetic symptoms. We tested the effects of the kappa agonist pentazocine in patients in the manic phase of bipolar disorder to determine if pentazocine might reduce symptoms of mania without worsening psychosis. In an open-label, add-on, single-day acute-dose study, ten in-patients with bipolar disorder, type 1, hospitalized for mania received two 50 mg doses of pentazocine 2 h apart. Symptoms of mania were reduced 1 h after each dose, 44% after the first dose and 41% 1 h after the second dose (F=3.69, p=0.01). No adverse effects, including psychotomimetic effects were observed or reported. Sedation was minimal. Further study of pentazocine and other kappa agonists in mania seems warranted.