An Overview of Controlled Substances

controlled substance is generally a drug or chemical whose manufacture, possession, or use is regulated by a government, such as illicitly used drugs or prescription medications that are designated by law. Some treaties, notably the Single Convention on Narcotic Drugs, the Convention on Psychotropic Substances, and the United Nations Convention Against Illicit Traffic in Narcotic Drugs and Psychotropic Substances provide internationally agreed upon “schedules” of controlled substances, which have been incorporated into national laws, however national laws usually significantly expand on these international convention.

Drugs or medications that possess the potential for being misused and are considered to be substances that have a substantially high risk of resulting in substance use disorder.

The control of drugs through law exists to protect people from the harm that these drugs can do. It is based on research from many different sources into the potential harmfulness of the drug, both to individuals and to society.

Schedule I Drugs

Schedule I drugs or substances have a high potential for abuse. They currently have no federally accepted medical use in treatment in the United States, and there is a lack of accepted safety for use of the drug or other substance under medical supervision.

Examples of Schedule I substances include heroin, lysergic acid diethylamide (LSD), marijuana, gamma-hydroxybutyric acid (GHB), and methaqualone.

Schedule II Drugs

Schedule II drugs or other substance also have a high potential for abuse. They differ from Schedule I drugs in that they do have a currently accepted medical use in treatment in the United States or a currently accepted medical use with severe restrictions.

Examples of Schedule II substances include morphine, phencyclidine (PCP), cocaine, methadone, and methamphetamine.

Schedule III Drugs

Schedule III drugs or other substances have less potential for abuse than the drugs or other substances in Schedules I and II. They have a currently accepted medical use in treatment in the United States. Abuse of the drug or other substance may lead to moderate or low physical dependence or high psychological dependence.

Examples of Schedule III substances include Anabolic steroids, codeine and hydrocodone with aspirin or Tylenol, and some barbiturates.

Schedule IV Drugs

The drug or other substance has a low potential for abuse relative to the drugs or other substances in Schedule III. The drug or other substance has a currently accepted medical use in treatment in the United States. Abuse of the drug or other substance may lead to limited physical dependence or psychological dependence relative to the drugs or other substances in Schedule III.

Examples of drugs included in Schedule IV are Darvon, Talwin, Equanil, Valium, and Xanax.

Schedule V Drugs

The drug or other substance has a low potential for abuse relative to the drugs or other substances in Schedule IV. The drug or other substance has a currently accepted medical use in treatment in the United States. Abuse of the drug or other substances may lead to limited physical dependence or psychological dependence relative to the drugs or other substances in Schedule IV.

Examples of Schedule V drugs include cough medicines with codeine.

Abusive Prescribing of Controlled Substances 

Pharmacies have a role to play in the oversight of prescriptions for controlled substances, and opioid analgesics in particular. Under the Controlled Substances Act, pharmacists must evaluate patients to ensure the appropriateness of any controlled-substance prescription. In addition, state boards of pharmacy regulate the distribution of opioid analgesics and other controlled substances through the discretion of pharmacists. Yet in the majority of cases of potential abuse, pharmacists face a patient who has a legal prescription from a licensed physician, and they have access to very little other background information. That makes it difficult for individual pharmacists to use their own partially informed judgment to identify prescriptions that have come from a pill-mill doctor.

Prescription of Controlled Substances:

One of the single most difficult challenges for any prescriber is to distinguish between the legitimate prescription of controlled substances versus the prescription potentially used for illegitimate purposes. To discern the difference prescribers need to understand the signs, symptoms, and treatment of acute and chronic pain as well as the signs and symptoms of patients using controlled substances for non-legitimate purposes. The Controlled Substance Act established five drug schedules and classified them to control their manufacture and distribution. Part of regulation requires providers that prescribe scheduled drugs and pharmacists that fill them to obtain a license from the Drug Enforcement Administration. Health professionals licenses include specific license numbers allowing controlled substance prescriptions to be tracked and linked to a particular provider or distributor. Of the five schedules, each has parameters based on their medical value, the risk of addiction, and ability to cause harm. The schedules range from schedule I (most potential for addiction and use disorder) to schedule V (least potential for addiction/use disorder).

High Risk Prescribing and Opioid Overdose:

The proliferation of prescription opioids has become a critical public health issue in the United States (US), Canada, and, increasingly, Europe, Australia and New Zealand . In the US, prescriptions for opioid analgesics have quadrupled over the past two decades. Prescription opioid overdoses claimed over 14,000 lives in the US in 2014. Previous studies have found an association between opioid prescription and rates of overdose mortality The increase in opioid related mortality has prompted scrutiny of prescription drug misuse, diversion, and “doctor shopping.” PDMPs have been implemented in 49 States, most of which allow clinicians to track patient prescription histories .

Risk factors for serious prescription opioid-related toxicity

Substantial risk for serious opioid-related toxicity and overdose exists at even relatively low maximum prescribed daily MED, especially in patients already vulnerable due to underlying demographic factors, comorbid conditions, and concomitant use of CNS depressant medications or substances. Screening patients for risk, providing education, and co-prescribing naloxone for those at elevated risk may be effective at reducing serious opioid-related respiratory/CNS depression and overdose in medical users of prescription opioids. Opioids depress the central nervous system (CNS), which may result in profound and potentially fatal respiratory depression, sedation, and coma. Prescription opioid‐related deaths in the United States have almost quadrupled since 1999, to 16,917 in 2011, with approximately 80% of fatal opioid‐related overdoses classified as unintentional.