What is a controlled substance?

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Medically reviewed by Neil Chatterjee, MD

Controlled substances are a group of prescription medications or illicit drugs that the government regulates due to their high potential for abuse and addiction. Prescription pharmaceutical controlled substances include opioids, depressants, stimulants, hallucinogens, and anabolic steroids.  

Controlled Substances Act

In 1971, Congress enacted the Controlled Substances Act, also known as the Federal Comprehensive Drug Abuse Prevention and Control Act of 1970, to improve the distribution and dispense of controlled substances. As a result, manufacturers, distributors, and dispensers must be registered with the Drug Enforcement Administration (DEA). Controlled substances are traceable from the initial manufacturing process to the final dispensing process.   

Classification of Controlled Substances

Controlled substances are categorized into five schedules based on their abuse potential, dependency potential, and how dangerous they are. The five classifications are rated based on several factors and years of research.  

Schedule I Controlled Substances

These are the most dangerous of all drugs. All the substances are illicit drugs not indicated for medicinal use except Marijuana, which is legal for recreational and medicinal use in some states. These drugs have a high potential for physical and psychological dependence and are easy to abuse. 

  • Some examples of Schedule I drugs are LSD, heroin, marijuana, Ecstasy, peyote, methaqualone. 

Schedule II Controlled Substances 

These are a group of drugs that have a high addiction and abuse potential. Unlike Scheduled I drugs, these are all accepted and approved for medicinal use in the United States with several restrictions and limitations.  

  • Examples of narcotics in this category include methadone, deperidine (Demerol), oxycodone (Percocet, Oxycontin), fentanyl, morphine, codeine. Examples of Schedule II stimulants include amphetamine (Adderall), methamphetamine, and methylphenidate (Ritalin).  
  • Examples of Schedule II barbiturates include: amobarbital and pentobarbital.
  • Examples of Schedule II sedatives include: glutethimide, a drug that has very little clinical use and has been replaced with benzodiazepines. 

Schedule III Controlled Substances 

This group includes drugs with abuse and addiction potential, but less than Schedule I and II medications. These may lead to moderate to low physical and psychological dependence.  

  • Examples of Schedule III narcotics include buprenorphine (Suboxone) and Tylenol with Codeine. The substances in this category are products containing no more than 90 milligrams of codeine per dose unit.  
  • Examples of non-narcotics in this group include phendimetrazine, ketamine, and anabolic steroids such as Depo-Testosterone. 

Schedule IV Controlled Substances 

These medications have a lower abuse potential compared to those in Schedule III. Most of the benzodiazepines or sedatives are in this category. These medications are indicated in several diagnoses and are typically recommended for short-term use in most cases. 

  • Examples of Schedule IVS substances include clonazepam (Klonopin), diazepam (Valium), midazolam (Versed), alprazolam (Xanax), and temazepam (Restoril).  

Schedule V Controlled Substances

These are medications for low abuse and addiction risk compared to the drug categories mentioned above. Many of the cough suppressants with codeine are included in this group. These cough preparations in this group of medications contain no more than 200 milligrams of codeine per 100 milliliters or per 100 grams. 

  • Examples include: Robitussin and Phenergan with Codeine. Ezogabine is a drug in this category used for certain patients with epilepsy.

Important Safety Tips When Prescribed a Controlled Substance

If your physician prescribes you a controlled substance, there are many precautions that you need to take for your and your family’s safety. These are dangerous drugs that either have a high potential for abuse and addiction or come with significant physical and psychological consequences. 

  1. Keep the medications in a locked safe or away from anybody, especially children.  
  2. When traveling, only pack the exact amount of drugs you need rather than taking entire bottles of pills with you.
  3. Prevent unauthorized access to your medications.
  4. Pay attention to specific signs and symptoms that may allude to potential addiction.
  5. Always keep a count of your medications and let your doctor know if you require more than prescribed.
  6. Report any stolen medicines to your doctor and immediately file a police report for documentation.
  7. Never mix any other medications without consulting your healthcare provider.

This post is intended for general informational purposes only and does not address any individual circumstances. It is not a substitute for professional medical advice, diagnosis or treatment. When in doubt, speak to your doctor.

If you think you may be experiencing overdose or have any other medical emergency, immediately call your doctor or dial 911.

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