Pharmacokinetics of coadministered guanfacine extended release and lisdexamfetamine dimesylate.

BACKGROUND: In clinical practice, α2-adrenoceptor agonists have been adjunctively administered with psychostimulants for the treatment of attention-deficit/hyperactivity disorder (ADHD). Two studies have examined the adjunctive use of guanfacine extended release (GXR, Intuniv®; Shire Development LLC, Wayne, PA, USA) with psychostimulants in children and adolescents with a suboptimal response to psychostimulant treatment. However, the potential for pharmacokinetic drug-drug interactions (DDIs) between GXR and lisdexamfetamine dimesylate (LDX, Vyvanse®; Shire US LLC, Wayne, PA, USA) has not been thoroughly evaluated. OBJECTIVE: The primary objective of this study was to examine the pharmacokinetics of GXR 4 mg and LDX 50 mg given as single doses alone and in combination. STUDY DESIGN: This was an open-label, randomized, three-period crossover, DDI study. SETTING: The study was conducted in a single clinical research center. PARTICIPANTS: Forty-two healthy adults were randomized in this study. INTERVENTIONS: Subjects were administered single oral doses of GXR 4 mg, LDX 50 mg, or GXR and LDX in combination. MAIN OUTCOME MEASURES: Blood samples collected predose and up to 72 h postdose assessed guanfacine, LDX, and d-amphetamine levels. Bioequivalence was defined as the 90% confidence intervals (CIs) of the geometric mean ratios of the area under the plasma concentration-time curve extrapolated to infinity (AUC0-∞) and maximum plasma concentration (Cmax) falling within the bioequivalence reference interval (0.80-1.25). Safety measures included adverse events, vital signs, and electrocardiograms (ECGs). RESULTS: Forty subjects completed the study. Following administration of LDX alone or in combination with GXR, the statistical comparisons of the AUC0-∞ and Cmax of d-amphetamine fell entirely within the reference interval. For guanfacine, the 90% CI of the geometric mean ratio of AUC∞ for the two treatments was within the bioequivalence criteria, but for Cmax the upper bound of the 90% CI exceeded the standard range for bioequivalence by 7%. This relatively small change is unlikely to be clinically meaningful. Treatment-emergent adverse events (TEAEs) were reported by 42.9% of subjects; the most commonly reported TEAEs included dizziness (5.0, 7.3, and 7.3%) and headache (7.5, 4.9, and 7.3%) following administration of GXR, LDX, and GXR and LDX in combination, respectively. Clinically significant ECG abnormalities occurred in one subject following administration of LDX and in one subject following coadministration of GXR and LDX. CONCLUSIONS: In healthy adults, coadministration of GXR and LDX did not result in a clinically meaningful pharmacokinetic DDI compared with either treatment alone. No unique TEAEs were observed with coadministration of GXR and LDX compared with either treatment alone.

Food insufficiency and physical and mental health in a longitudinal survey of welfare recipients.

Food insufficiency is a significant problem in the United States, and poor African American women with children are at especially high risk. An inadequate household food supply can potentially affect the well-being of household members, but it is difficult to distinguish the effects of food insufficiency from risk factors for poor health that are also common among the food insufficient, such as poverty. We examined food insufficiency and physical and mental health among African American and white women (n = 676) who were welfare recipients in 1997. Controlling for common risk factors, women who reported food insufficiency in both 1997 and 1998 were more likely to report fair or poor health at the later date. Food insufficiency in 1998 was significantly associated with meeting the diagnostic screening criteria for recent major depression. Food insufficiency at both times and in 1998 only was related to women's sense of mastery. These findings add to growing evidence that household food insufficiency is associated with poor physical and mental health.