Olanzapine pharmacokinetics in pediatric and adolescent inpatients with childhood-onset schizophrenia.

Well-designed studies investigating how pediatric or adolescent patients with mental disorders respond to and metabolize the newer antipsychotic drugs are practically nonexistent. Without such data, clinicians have difficulty designing appropriate dosage regimens for patients in these age groups. The results from a study of olanzapine pharmacokinetics in children and adolescents are described. Eight inpatients (ages 10-18 years) with treatment-resistant childhood-onset schizophrenia received olanzapine (2.5-20 mg/day) over 8 weeks. Blood samples, collected during dose titration and at a steady state provided pharmacokinetic data. The final evaluation (week 8) included extensive sampling for 36 hours after a 20-mg dose. Olanzapine concentrations in these eight pediatric patients were of the same magnitude as those for nonsmoking adult patients with schizophrenia but may be as much as twice the typical olanzapine concentrations in patients with schizophrenia who smoke. Olanzapine pharmacokinetic evaluation gave an apparent mean oral clearance of 9.6 +/- 2.4 L/hr and a mean elimination half-life of 37.2 +/- 5.1 hours in these young patients. The determination of the initial olanzapine dose for adolescent patients should take into consideration factors such as the patient's size. In general, however, the usual dose recommendation of 5 to 10 mg once daily with a target dose of 10 mg/day is likely a good clinical guideline for most adolescent patients on the basis of our pharmacokinetics results.

The effect of sertraline on the pharmacokinetics of desipramine and imipramine.

OBJECTIVE: To examine the pharmacokinetic interaction between the selective serotonin reuptake inhibitor sertraline and the tricyclic antidepressants desipramine or imipramine in 12 healthy male subjects. METHODS: Participants received a 50 mg single dose of either desipramine or imipramine under three conditions: alone, after a single 150 mg dose of sertraline, and after the eighth daily 150 mg dose of sertraline. Plasma samples were analyzed for desipramine or imipramine concentration by HPLC with electrochemical detection, and pharmacokinetics were determined with use of noncompartmental analysis of individual data. RESULTS: Multiple-dose, but not single-dose, treatment with sertraline significantly reduced apparent plasma clearance (CL/F) and prolonged the half-life of desipramine relative to baseline. These changes resulted in higher plasma desipramine concentrations, as indicated by a significant increase in maximum plasma concentration (Cmax) and area under the plasma concentration-time curve extrapolated to infinity [AUC(0-infinity)] (22% and 54%, respectively). Both single- and multiple-dose treatment with sertraline significantly reduced the CL/F of imipramine. This effect was stronger after multiple predoses of sertraline, when imipramine Cmax and AUC(0-infinity) were increased by 39% and 68%, respectively. These treatment effects were consistent between individuals. CONCLUSIONS: This pharmacokinetic interaction is likely the result of an inhibition of CYP2D6 tricyclic metabolism by sertraline. When a tricyclic antidepressant, such as desipramine or imipramine, is coadministered with sertraline, lower dosages of the tricyclic agents may be necessary to prevent elevated tricyclic levels.

Genetic differences in tolerance and sensitization to the sedative/hypnotic effects of alcohol.

Initial sensitivity to alcohol and the development of alcohol tolerance were examined in rats of the selectively bred alcohol-preferring (P) and -nonpreferring (NP) lines. All rats received two alcohol injections (3.0 g/kg b.wt., IP) separated by either 1 or 2 days. P rats were less sensitive to the behaviorally impairing effects of alcohol than were NP rats, as evidenced by a longer latency to lose righting reflex (RR) and a shorter time to recover RR following an initial alcohol injection. When 1 day separated the two alcohol injections, P rats recovered the RR more rapidly following a second injection compared to the first, indicating that the P rats developed tolerance to the sedative/hypnotic effects of alcohol. In contrast, the NP rats recovered the RR more slowly following the second injection compared to the first, indicating that the NP rats developed sensitization to alcohol. Tolerance in the P line and sensitization in the NP line disappeared when 2 days separated the two alcohol injections. Line differences in initial sensitivity and tolerance/sensitization to the behaviorally impairing effects of alcohol may contribute to the differences in alcohol consumption observed in the P and NP lines.

The delta opioid receptor antagonist naltrindole attenuates both alcohol and saccharin intake in rats selectively bred for alcohol preference.

This study demonstrates that the selective delta receptor antagonists ICI 174864 and naltrindole (NTI) attenuate alcohol intake in a dose-dependent manner, without altering water intake, in rats selectively bred for alcohol preference. ICI 174864 had a very limited duration of action, as evidenced by the fact that suppression of alcohol intake lasted for only an hour following ICI 174864 administration. NTI, when administered in a dose of 10 mg/kg, suppressed alcohol intake by 28%. Increasing the dose of NTI to 15 mg/kg produced a 44% suppression of alcohol intake, but a further increase to 20 mg/kg did not produce greater suppression than was seen with a dose of 15 mg/kg (46% versus 44%, respectively). This suggests that NTI is maximally effective in suppressing alcohol intake at a dose of 15.0 mg/kg. NTI displayed a long duration of action, as evidenced by attenuation of alcohol drinking that lasted for at least 8 h following drug treatment. Administering the maximally effective dose of NTI (15 mg/kg) in two parts, separated by 4 h, served to prolong the duration of action of NTI and produced an attenuation of alcohol intake, but not water intake, that lasted for at least 28 h. The effect of NTI on alcohol intake was not specific for alcohol, as evidenced by the fact that NTI reduced the intake of saccharin solutions with and without alcohol.

Differences in the hypothermic response to ethanol in rats selectively bred for oral ethanol preference and nonpreference.

The duration of retention of tolerance to ethanol was tested in the alcohol-preferring (P) and alcohol-nonpreferring (NP) rats lines, using ethanol-induced hypothermia as a measure of tolerance. Rats received two injections of ethanol (3.5 g/kg) body wt, IP) and the time between the injections was 1, 2, or 3 days. When one day separated the two injections, tolerance to the hypothermic effect of a second "test" injection was found in both lines. When 2 or 3 days separated the two injections, the P line showed a loss of tolerance and the NP line showed sensitization to ethanol. Sensitization in the NP line grew stronger when the interval between injections was increased from 2 to 3 days. The duration of retention of tolerance to ethanol-induced hypothermia in the P line was shorter than has previously been reported for motor impairment in this line. It appears that the duration of tolerance retention in the P line depends on the test used to measure tolerance. Sensitization to ethanol in the NP line may be associated with low oral ethanol intake.

AIDS and the marketing of condoms.

PIP: The condom market has undergone unprecedented change in the 1980's and will continue to see its markets, advertising strategies, and sales grow and change in ways never before imagined. In the past, condoms were viewed as unmentionable products that were marketed only at men between 18 and 35 and sold only in gas station restrooms and bus stations. But today women account for and estimated 40-50% of condom sales and after a Supreme Court ruling in 1977, condoms are now sold in front of the counter, not behind it. Further, the AIDS epidemic which has afflicted 40,000 U.S. citizens between 19811 and 1988 has served as an impetus to growth and diversification of the condom market. The new legitimacy of the condom combined with new entries into the market by other manufacturers has resulted in growth and segmentation in the condom market.^ieng