Single Dose Pharmacokinetic and Pharmacodynamic Evaluation of Three Different Doses of Zolpidem in Children

Inclusion Criteria: 1. Male or female between the ages of 2 years and 18 years. 2. Written consent must be obtained form the parent/legal guardian for all minors. Written assent must be obtained from all minors \> 6 years of age. 3. Female subjects of child-bearing potential must not be pregnant and if females are fertile and sexually active, must have documented a negative urine HCG and assure use of effective contraception acceptable to the investigator (abstinence accepted) during the study period. 4. Subjects must meet the following criteria for a diagnosis of insomnia as determined by the subject's private physician or study investigator and subject's history: * the complaint is significant difficulty (defined by frequency, severity, and/or chronicity) initiating or maintaining sleep;. The problem is viewed problematic by the child and/or caregiver; * the sleep disturbance causes clinically significant impairment in school performance, behavior, learning, or development for the child as reported by the child and/or caregiver; * the sleep disturbance does not occur exclusively in the context of an intrinsic dyssomnia such as narcolepsy, restless legs syndrome, or sleep-related breathing disorders; a circadian rhythm disorder; or a parasomnia; * the sleep disturbance is not attributable to either the direct physiologic effect of a drug of abuse or misuse of a prescribed medication. Exclusion Criteria: 1. Pregnancy and/or breastfeeding; 2. The presence of any untreated (where treatment is available), or unstable, progressive, or evolving clinically significant renal, endocrine, hepatic, respiratory, cardiovascular, neurologic, hematologic, immunologic, cerebrovascular disease or malignancy; 3. Elevations in screening blood tests of renal (SCr) and liver (ALT, AST and/or bilirubin) \> 2 times the upper limit of normal for age. 4. Receiving any medications that may modulate Zolpidem metabolism, primarily drugs that will enhance or reduce the activity of CYP450 3A, 2C9, or 2D6 activity. Note: If patient is receiving a medication that might be considered an inducer or an inhibitor, please discuss with the PI prior to excluding them. 5. Receiving any medications with sleep-impairing properties at a dose/dose interval that would be judged by the study investigator as to interfere with the assessment of Zolpidem sleep response. 6. Currently using any systemic contraceptive steroids including: oral contraceptives, transdermal patch, vaginal insert, levonorgestrel implant and medroxyprogesterone acetate contraceptive injection.