Antipsychotic-induced priapism in an HIV patient: a cytochrome P450-mediated drug interaction.

BACKGROUND: With upwards of 48% of human immunodeficiency virus (HIV)-infected persons having a probable psychiatric disorder, the possibility of cross-class drug interactions causing adverse effects or fatalities exists. AIMS: This report discusses an emergent case of low-flow priapism caused by an interaction between a previously prescribed combination protease inhibitor (PI) and newly added antipsychotic medications. METHODS: A 50-year-old HIV-positive man on highly active antiretroviral therapy (HAART), including the combination PI, lopinavir/ritonavir (Kaletra((R))), experienced an episode of priapism hours after beginning two new antipsychotic medications. Quetiapine (Seroquel((R))) and perphenazine (Trilafon((R))) were added to treat a diagnosed schizoaffective disorder. RESULTS: The patient presented to the emergency department complaining of a constant, painful erection lasting approximately 42 h. Treatment with intracavernous ephedrine, irrigation, and aspiration helped achieve detumescence. CONCLUSION: This case displays the immediate and detrimental effects due to the addition of antipsychotic medications to previously altered cytochrome P450 (CYP450) enzyme levels. The inhibition of CYP450 enzymes 3A4 and 2D6 by the combination PI, lopinavir/ritonavir, was likely the major culprit in causing greater than expected free levels of perphenazine and quetiapine resulting in priapism.

Effects of the HEET garment in the prevention of hypothermia in a porcine model.

BACKGROUND: Hypothermia is a common battlefield trauma occurrence. This study compared the effectiveness of the hypothermia, environmental, exposure, and trauma (HEET) garment (Trident Industries, Beaufort, SC) with and without thermal inserts with a control group of two wool blankets in the prevention of hypothermia in a treated hypovolemic porcine model. MATERIALS AND METHODS: Five female swine (Sus scrofa-Yorkshire cross) were assigned to each of three groups: HEET with thermal inserts (n=5); HEET without thermal inserts (n=5); or control (n=5). After the animals were anesthetized and stabilized for 30 min, the swine were hemorrhaged to a mean arterial pressure (MAP) of 30 mm Hg, simulating a battlefield injury. Hetastarch 6% (500 mL) was rapidly administered, simulating initial field resuscitation. One hour later, the animals' shed blood was reinfused, simulating transfusion at a field medical facility. The investigators moved the animal into a cooler set at 10°C ± 0.5°C. A pulmonary artery catheter was used to monitor core body temperature over a 6-h period. RESULTS: A repeated measures ANOVA and Tukey's post hoc test were used to analyze the data. There was a significant difference between the groups. At the end of 6h, the mean core temperature for the HEET with inserts group was 32.69°C ± 1.5; the HEET without inserts, 31.02°C ± 1.8; and control, 34.78°C ± 1.2 (P<0.05). While all groups became hypothermic, the wool blanket group was most effective in maintaining body temperature closer to normothermia. CONCLUSION: The HEET garments with and without heaters are ineffective in preventing hypothermia.