Controlled Substance Schedules

The Drug Enforcement Administration (DEA) classifies controlled substances into five schedules based on their potential for abuse, medical use, and safety profile. Understanding these schedules is critical for the ExCPT exam and daily pharmacy practice.

The Controlled Substances Act (CSA)

The Controlled Substances Act of 1970 is the federal law that regulates the manufacture, importation, possession, use, and distribution of certain substances. It established the five-schedule classification system still used today.

Key Regulatory Body: The Drug Enforcement Administration (DEA) enforces the CSA and maintains the list of controlled substances.

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DEA Schedule Classification System

*Note: Marijuana remains Schedule I federally, though some states have legalized medical or recreational use.

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Schedule I (C-I) Controlled Substances

Schedule I drugs have the highest potential for abuse and no currently accepted medical use in the United States.

Characteristics

• No prescriptions are permitted
• Available only for research with special DEA authorization
• Manufacturing and distribution severely restricted
• Highest penalties for illegal possession

Common Schedule I Examples

• Heroin - Illicit opioid
• LSD (lysergic acid diethylamide) - Hallucinogen
• Marijuana/Cannabis - Federally illegal (state laws vary)
• MDMA (Ecstasy/Molly) - Stimulant/hallucinogen
• Peyote - Hallucinogen (mescaline)

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Schedule II (C-II) Controlled Substances

Schedule II drugs have high potential for abuse but have accepted medical uses. These require the strictest prescription controls.

Characteristics

• Written prescription required (electronic prescriptions permitted in most states)
• No refills permitted - new prescription required each time
• Pharmacist cannot modify quantity or duration
• Emergency dispensing allowed with specific follow-up requirements
• 90-day supply limit in most states

Common Schedule II Examples

Exam Tip

Schedule II prescriptions cannot be refilled. If a question asks about refilling oxycodone or Adderall, the answer is a new prescription is required.

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Schedule III (C-III) Controlled Substances

Schedule III drugs have moderate to low potential for abuse and accepted medical uses.

Characteristics

• Written, oral, or electronic prescriptions accepted
• Refills permitted: up to 5 refills within 6 months
• May be called in by pharmacist or prescriber
• Less stringent storage requirements than C-II

Common Schedule III Examples

• Buprenorphine (Subutex, Suboxone) - Opioid use disorder treatment
• Ketamine - Anesthetic
• Anabolic steroids - Testosterone, nandrolone
• Codeine combinations - Tylenol #3 (acetaminophen with codeine)

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Schedule IV (C-IV) Controlled Substances

Schedule IV drugs have low potential for abuse relative to Schedule III substances.

Characteristics

• Same prescription requirements as Schedule III
• Refills permitted: up to 5 refills within 6 months
• Lower security requirements

Common Schedule IV Examples

• Benzodiazepines - Alprazolam (Xanax), diazepam (Valium), lorazepam (Ativan), clonazepam (Klonopin)
• Sleep aids - Zolpidem (Ambien), eszopiclone (Lunesta), zaleplon (Sonata)
• Tramadol - Pain reliever (reclassified to C-IV in 2014)
• Phenobarbital - Anticonvulsant

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Schedule V (C-V) Controlled Substances

Schedule V drugs have the lowest potential for abuse among controlled substances.

Characteristics

• Least restrictive among controlled substances
• Some may be dispensed without a prescription in certain states (pharmacist oversight required)
• Refills permitted: up to 5 refills within 6 months

Common Schedule V Examples

• Cough preparations with codeine - Robitussin AC, Cheratussin AC
• Pregabalin (Lyrica) - Nerve pain, seizures
• Lacosamide (Vimpat) - Seizures
• Ezogabine - Seizures

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DEA Registration Requirements

All entities handling controlled substances must register with the DEA.

Who Must Register

• Pharmacies
• Hospitals
• Prescribers (physicians, dentists, nurse practitioners, etc.)
• Manufacturers
• Distributors

Registration Details

• DEA registration number assigned to each registrant
• Registration renewed every 3 years
• Separate registration required for each location
• DEA number has specific format for verification

DEA Number Format

The DEA number consists of:

1. First letter: Registrant type (A/B for dispensers, M for mid-level practitioners, F for manufacturers)
2. Second letter: First letter of registrant's last name
3. Seven digits: The sum of 1st + 3rd + 5th digits plus twice (2nd + 4th + 6th digits) must equal a number ending in the 7th digit

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Controlled Substance Record Keeping

Pharmacies must maintain detailed records of all controlled substance transactions.

Record Requirements

• Invoices - Must be kept for 2 years minimum (some states require longer)
• DEA Form 222 - Required for Schedule II ordering (or electronic CSOS)
• Biennial inventory - Physical count required every 2 years
• Loss/theft reports - DEA Form 106 for theft or significant loss

Inventory Requirements

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Key Takeaways

• The Controlled Substances Act (CSA) established five schedules based on abuse potential and medical use.
• Schedule I drugs have no accepted medical use and high abuse potential (e.g., heroin, LSD).
• Schedule II drugs have high abuse potential but accepted medical uses (e.g., oxycodone, morphine).
• Schedules III-V have progressively lower abuse potential and fewer restrictions.
• DEA registration is required for all facilities and practitioners handling controlled substances.