One average square inch (6.5 cm2) of skin holds 650 sweat glands, 20 blood vessels, 60,000 melanocytes, and more than 1,000 nerve endings. The average human skin cell is about 30 micrometres (μm) in diameter, but there are variants. A skin cell usually ranges from 25 to 40 μm2, depending on a variety of factors. Skin is composed of three primary layers: the epidermis, the dermis and the hypodermis. Epidermis
Epidermis, "epi" coming from the Greek meaning "over" or "upon", is the outermost layer of the skin. It forms the waterproof, protective wrap over the bodys surface which also serves as a barrier to infection and is made up of stratified squamous epithelium with an underlying basal lamina. The epidermis contains no blood vessels, and cells in the deepest layers are nourished almost exclusively by diffused oxygen from the surrounding air and to a far lesser degree by blood capillaries extending to the outer layers of the dermis. The main type of cells that make up the epidermis are Merkel cells, keratinocytes, with melanocytes and Langerhans cells also present. The epidermis can be further subdivided into the following strata (beginning with the outermost layer): corneum, lucidum (only in palms of hands and bottoms of feet), granulosum, spinosum, and basale. Cells are formed through mitosis at the basale layer. The daughter cells (see cell division) move up the strata changing shape and composition as they die due to isolation from their blood source. The cytoplasm is released and the protein keratin is inserted.
The drug reaches peak concentration in about 2 hours and has a half life in healthly adults of about 2-3 hours. Zolpidems half life is decreased in children and increased in the elderly and people with liver issues. While some studies show men metabolize zolipdem faster than women (possibly due to testosterone), others do not. A review found only a 33% lower clearance in women compared to men, suggesting the FDAs dosage reduction of 50% for women may have been too large. Interactions
People should not consume alcohol while taking zolpidem, and should not be prescribed opioid drugs nor take such illicit drugs recreationally. Opioids can also increase the risk of becoming psychologically dependent on zolpidem. Use of opioids with zolpidem increases the risk of respiratory depression and death. The US Food and Drug Administration (FDA) is advising that the opioid addiction medications buprenorphine and methadone should not be withheld from patients taking benzodiazepines or other drugs that depress the central nervous system (CNS).Next day sedation can be worsened if people take zolpidem while they are also taking antipsychotics, other sedatives, anxiolytics, antidepressant agents, antiepileptic drugs, and antihistamines. Some people taking antidepressants have had visual hallucinations when they also took zolpidem.Cytochrome P450 inhibitors, particularly CYP3A4 and CYP1A2 inhibitors such as fluvoxamine, ciprofloxacin, and clarithromycin will increase the effects of a given dose of zolpidem. Cytochrome P450 activators like St. Johns Wort may decrease the activity of zolpidem.