Transdermal patches (adhesive patches placed on the skin) may also be used to deliver a steady dose through the skin and into the bloodstream. Testosterone-containing creams and gels that are applied daily to the skin are also available, but absorption is inefficient (roughly 10%, varying between individuals) and these treatments tend to be more expensive. Individuals who are especially physically active and/or bathe often may not be good candidates, since the medication can be washed off and may take up to six hours to be fully absorbed. There is also the risk that an intimate partner or child may come in contact with the application site and inadvertently dose himself or herself; children and women are highly sensitive to testosterone and can suffer unintended masculinization and health effects, even from small doses. Injection is the most common method used by individuals administering AAS for non-medical purposes. 
Prescribing data from Medicare’s prescription drug benefit, known as Part D, was compiled and released by the Centers for Medicare and Medicaid Services, the federal agency that oversees the program. The data for 2015 includes more than billion prescriptions written by nearly million doctors, nurses and other providers. This database lists about 447,000 of those providers who wrote 50 or more prescriptions for at least one drug that year. More than three-fourths of these prescriptions went to patients 65 and older; the rest were for disabled patients. Methodology »
Most drugs of abuse are addictive. Addiction is a chronic, relapsing disease characterized by compulsive drug seeking and use despite negative consequences and by long-lasting changes in the brain. People who are addicted have strong cravings for the drug, making it difficult to stop using. Most drugs alter a person’s thinking and judgment, which can increase the risk of injury or death from drugged driving or infectious diseases (., HIV/AIDS, hepatitis) from unsafe sexual practices or needle sharing. Drug use during pregnancy can lead to neonatal abstinence syndrome, a condition in which a baby can suffer from dependence and withdrawal symptoms after birth. Pregnancy-related issues are listed in the chart below for drugs where there is enough scientific evidence to connect the drug use to negative effects. However, most drugs could potentially harm an unborn baby.