Interaction of triazolam with desipramine. Effects of single and repeated treatment on certain pharmacologic responses and brain catecholamine levels.

The present study was undertaken to evaluate the effects of single and repeated doses of triazolam (1 mg/kg IP) and desipramine (DMI) (10 mg/kg IP) alone and in combination on certain pharmacologic responses and brain catecholamine levels in rats. The significant findings were: (1) triazolam and DMI given alone and in combination were synergistic with pentobarbital (PB) hypnosis; (2) repeated treatment with DMI alone repressed body weight gain; triazolam potentiated this anorectic effect; (3) triazolam induced muscle relaxation acutely, but was not affected by concomitant DMI treatment; and (4) triazolam and DMI given in combination produced hypothermia although the drugs given separately did not. Development of tolerance to hypothermia and to anorectic effects produced by triazolam and DMI significantly decreased norepinephrine (NE) levels in the hypothalamus as compared to the repeated treatment with triazolam, and significantly increased NE and dopamine (DA) levels in the striatum and DA levels in the cortex, as compared to the single treatments.