DEA drug schedules for the PTCE: I to V

Controlled substances sit inside the PTCE's Federal Requirements domain (18.75% of the 2026 outline), and questions on them mix drug recall with rules on prescriptions and refills. This guide covers the schedules and the refill rules that go with them. The source is the DEA Pharmacist's Manual and 21 CFR, as verified in Encodr's PTCB fact files.

The five schedules

The Controlled Substances Act sorts drugs into Schedules I through V. The DEA enforces it, and its Diversion Control Division regulates pharmacies.

• Schedule I: high abuse potential and no currently accepted medical use. Examples: heroin, LSD, peyote, methaqualone and MDMA.
• Schedule II: high abuse potential, accepted medical use, and abuse may lead to severe dependence. Examples: morphine, oxycodone, fentanyl, hydromorphone, methadone, meperidine, and stimulants like amphetamine (Adderall), methylphenidate (Ritalin) and lisdexamfetamine (Vyvanse). All hydrocodone combination products are Schedule II.
• Schedule III: lower abuse potential than I and II. Examples: products with not more than 90 mg of codeine per dosage unit combined with a non-narcotic (Tylenol with codeine), buprenorphine for opioid addiction, testosterone and other anabolic steroids, and ketamine.
• Schedule IV: low abuse potential relative to III. Examples: tramadol, benzodiazepines such as alprazolam, clonazepam, diazepam and lorazepam, and zolpidem, carisoprodol, modafinil and phentermine.
• Schedule V: the lowest. Examples: cough preparations with not more than 200 mg of codeine per 100 mL, diphenoxylate with atropine, and pregabalin. Gabapentin is not listed in any federal schedule, though some states control it.

Only Schedule I has no accepted medical use. Marijuana's status changed in 2026: as of the date these facts were checked, marijuana in FDA-approved products and under state medical licenses moved to Schedule III, while other marijuana stayed in Schedule I. Check the current rule before you rely on that.

Refill rules by schedule

• Schedule II may never be refilled. No transfer for refill either.
• Schedules III and IV: not filled or refilled more than 6 months after the issue date, and not refilled more than 5 times. Whichever limit comes first, the patient needs a new prescription.
• Schedule V: federal rules set no refill limit, but many states do.
• CIII to CV prescription information may be transferred between pharmacies for refill purposes one time only, if state law allows.

Two Schedule II situations worth knowing

• Emergency oral prescriptions: a pharmacist may dispense on oral authorization, limited to the emergency amount, and must reduce it to writing. The prescriber must deliver a written or electronic prescription within 7 days.
• Partial fills: if the pharmacist cannot supply the full quantity, the remainder must be supplied within 72 hours of the first partial fill.

Study it with retrieval, not lists

Schedule tables are a classic case for spaced retrieval: cover the schedule and produce the drugs, then flip it. How to memorize the top 200 drugs applies the same approach to drug names, and PTCE passing score: what 1,400 really means shows where this domain fits. Days supply questions often involve controlled substances, so the days supply calculator is a useful companion, and days supply calculation: formula and traps covers the math.

Encodr's free PTCB exam course gives controlled substances their own unit. See every course on the exam prep hub.