Veterinary Schedule II, III & IV Controlled Substances: DEA Requirements Guide

Why Drug Schedules Matter for Compliance

The DEA's controlled substance scheduling system — established under the Controlled Substances Act (CSA) — determines both the legal authority requirements for handling a drug and the specific record-keeping obligations that apply. Schedule I is the most restrictive (no accepted medical use); Schedule V is the least restrictive.

For veterinary practices, the practical focus is almost always on Schedules II through IV, where the commonly used anesthetics, analgesics, and sedatives fall. Getting the schedule classification wrong — or applying the wrong record-keeping rules — is one of the most common sources of DEA violations at veterinary practices.

Schedule II Veterinary Controlled Substances

Schedule II drugs have a high potential for abuse, currently accepted medical use, and potential for severe psychological or physical dependence. In veterinary practice, Schedule II drugs are used primarily for pain management, anesthesia, and euthanasia.

Commonly encountered Schedule II substances in veterinary practice include:

• Fentanyl — injectable and transdermal patch forms; widely used for perioperative analgesia in dogs and cats
• Morphine — injectable; used for moderate-to-severe pain in companion animals and horses
• Oxymorphone (Numorphan) — injectable; used for preanesthetic medication and postoperative analgesia
• Hydromorphone — injectable; increasingly common in companion animal practice as a fentanyl alternative
• Meperidine (Demerol) — injectable; less common but still used in some equine and exotic species practices
• Pentobarbital (Euthasol, Beuthanasia-D) — injectable; used for euthanasia; Schedule II in most states (some states classify it as Schedule III)
• Cocaine — topical solution; occasionally used in ophthalmic procedures in exotic species

Schedule III Veterinary Controlled Substances

Schedule III substances have less potential for abuse than Schedule I or II and have currently accepted medical uses. In veterinary practice, Schedule III drugs are some of the most frequently handled — and most frequently mismanaged.

Commonly encountered Schedule III substances in veterinary practice:

• Ketamine — injectable; the most commonly used Schedule III substance in veterinary practice. Used for induction, analgesia, and restraint across species. High diversion risk — see the ketamine deep dive below.
• Tiletamine/Zolazepam (Telazol) — injectable combination product; widely used for chemical restraint in wildlife and exotic species. Tiletamine is Schedule III; zolazepam is Schedule IV, making Telazol a Schedule III product overall.
• Butorphanol (Torbugesic, Torbutrol) — injectable and oral tablet; used for analgesia and cough suppression. One of the most commonly dispensed Schedule III veterinary drugs.
• Buprenorphine (Buprenex) — injectable; used for perioperative analgesia in cats and small mammals. Schedule III federally (as of 2023 rescheduling update — verify current status).
• Testosterone and anabolic steroids — injectable and implant; used in production animals and sport horses.

Schedule IV Veterinary Controlled Substances

Schedule IV substances have lower potential for abuse relative to Schedule III and accepted medical uses. This schedule contains several high-volume veterinary drugs, including common benzodiazepines and barbiturates.

Commonly encountered Schedule IV substances in veterinary practice:

• Diazepam (Valium) — injectable and oral; widely used for sedation, seizure management, and anesthesia induction
• Midazolam (Versed) — injectable; increasingly used for sedation, induction, and procedural analgesia
• Phenobarbital — oral and injectable; the most common anticonvulsant in veterinary medicine; high-volume dispensing at neurology practices
• Alfaxalone (Alfaxan) — injectable; used for anesthesia induction and TIVA in dogs and cats
• Tramadol — oral; Schedule IV federally; classification varies by state. Some states have added state-level scheduling controls above the federal baseline.
• Zolazepam — component of Telazol (see Schedule III above)
• Dexmedetomidine / Medetomidine — injectable; commonly used sedatives in companion animal practice. Currently not scheduled federally, though some states have added scheduling. Verify current status in your state.

Schedule V Veterinary Controlled Substances

Schedule V substances have the lowest potential for abuse among controlled substances and accepted medical uses. In veterinary practice, Schedule V drugs are less commonly handled but still require DEA recordkeeping.

• Pregabalin (Lyrica) — oral; used for neuropathic pain and seizures. Schedule V federally; some states have higher state-level controls.
• Cough preparations containing codeine (≤200 mg/100mL) — rarely used in veterinary practice but technically Schedule V

DEA Compliance Requirements by Schedule

The record-keeping obligations under 21 CFR Part 1304 vary by schedule. Here is a summary of the key differences:

Ketamine Deep Dive: Why It's the #1 Compliance Focus

Ketamine deserves special attention because it is the most commonly mismanaged controlled substance in veterinary practice — and the substance most frequently involved in diversion cases.

Despite being Schedule III (a lower compliance burden than Schedule II in theory), ketamine is:

• High-volume: Used daily in most veterinary hospitals for induction, analgesia, and restraint — creating many opportunities for record-keeping gaps
• High diversion risk: Ketamine (Special K) has significant street value and recreational abuse potential, making it a priority target for DEA diversion investigations
• Inconsistently documented:Because it is "only" Schedule III, some practices apply lighter oversight than they would to fentanyl — leading to running balance discrepancies that flag immediately in an audit
• Multi-vial tracking complexity: Ketamine is often drawn from partially used vials across multiple procedures, creating lot-level tracking challenges that paper logs handle poorly

The practical guidance: treat ketamine with Schedule II-level rigor in your internal protocols, even though the legal minimum for Schedule III is lower. DEA investigators know ketamine is the highest-diversion Schedule III substance in veterinary practice — and will scrutinize those records carefully.

Read our full guide on detecting and preventing controlled substance diversion for the specific patterns that flag ketamine diversion before month-end reconciliation.

State Law: When Schedules Differ

Federal DEA scheduling is a floor, not a ceiling. Individual states may schedule substances at a higher level than the federal CSA — or add substances to state schedules that are not federally scheduled at all.

Examples of state-level variations that affect veterinary practices:

• Pentobarbital:Schedule II federally; several states classify it as Schedule III for veterinary use. Verify your state's classification — it determines whether you need DEA-222 order forms.
• Tramadol: Schedule IV federally; some states classify it at higher levels or impose additional dispensing requirements.
• Gabapentin: Not federally scheduled; but Kentucky, Tennessee, Michigan, Tennessee, Minnesota, and several other states have added state-level Schedule V or similar controls. Verify your state.
• Butorphanol: Schedule IV in some states; Schedule III federally. State-specific rules apply.

5 Common Schedule Misconceptions

1. "Ketamine is just Schedule III, so we don't need dual-witness waste."

Federal law does not explicitly require dual-witness waste for Schedule III–V substances — but many state regulations do, and DEA investigators expect it as a best practice. Failing to have a second witness sign ketamine waste events is a red flag that gets noted in inspection reports even when it's not a formal violation.

2. "We don't use fentanyl anymore, so our Schedule II compliance burden is lower."

Euthanasia solutions (pentobarbital) are Schedule II in most jurisdictions. If your practice conducts euthanasias — which nearly every practice does — you have a Schedule II compliance obligation regardless of your anesthesia formulary.

3. "Phenobarbital is just a pill, so the rules are lighter."

Physical form (tablet vs. injectable) has no bearing on schedule classification. Oral phenobarbital is Schedule IV and requires the same dispensing log entries and biennial inventory documentation as injectable Schedule IV substances.

4. "We order ketamine from our distributor — we don't need special order forms."

Correct for Schedule III. DEA Form 222 (order forms) are only required for Schedule II purchases. Schedule III–V purchases can be made using standard distributor ordering processes, though a receiving record is still required.

5. "Our EMR tracks our drugs, so we're covered."

Most EMR drug modules track what was administered to a patient — not what was drawn, wasted, reversed, or counted blind. The DEA requires a controlled substance log that captures all of these events, not just administration records. For a detailed breakdown of why EMR modules fall short, see our comparison of VetRx Ledger vs. paper, Excel, and EMR modules.