Most muscle relaxers are not controlled substances under federal law. Two are: carisoprodol (sold as Soma), which the DEA placed on Schedule IV effective January 11, 2012, and diazepam (Valium), a benzodiazepine sometimes prescribed for muscle spasms that has been on Schedule IV since the original federal drug schedules took effect. Every other commonly prescribed muscle relaxer, including cyclobenzaprine, tizanidine, methocarbamol, baclofen, and metaxalone, sits outside the federal schedules. That said, “not controlled” is not the same as “no legal risk,” and a few of the risks catch people off guard.
The Two Muscle Relaxers That Are Controlled
Both carisoprodol and diazepam are Schedule IV, meaning the government recognizes an accepted medical use, a low potential for abuse relative to Schedule III drugs, and a risk of limited physical or psychological dependence.
Carisoprodol was moved onto Schedule IV on January 11, 2012. The DEA found that carisoprodol’s major metabolic pathway converts the drug into meprobamate, a barbiturate-like substance already on Schedule IV, and cited rising emergency-room visits and law enforcement encounters tied to carisoprodol misuse.1Federal Register. Schedules of Controlled Substances: Placement of Carisoprodol Into Schedule IV
Diazepam is better known as an anxiety medication, but it is FDA-approved as an adjunct therapy for skeletal muscle spasms at doses of 2 to 10 mg taken three to four times daily. As a benzodiazepine, it has carried Schedule IV status for decades.
If your prescription is for either drug, every rule that applies to controlled substances applies to you.
The Muscle Relaxers That Aren’t Controlled
The rest of the usual prescriptions are not federally scheduled. They still require a prescription, but pharmacies dispense them without the refill limits and tracking that controlled substances demand.
- Cyclobenzaprine (Flexeril, Amrix). The DEA’s own evaluation confirms cyclobenzaprine “is not controlled under the Controlled Substances Act.” It is probably the most frequently prescribed muscle relaxer in the country.2Drug Enforcement Administration. Cyclobenzaprine (Trade Name: Flexeril, Amrix)
- Tizanidine (Zanaflex). Not federally controlled. Prolonged use can produce dependence, but the DEA has not scheduled it.
- Methocarbamol (Robaxin). Not controlled. Low potential for abuse and no significant euphoric effects.
- Baclofen (Lioresal). Not federally controlled, but it carries serious withdrawal risks covered below.
- Metaxalone (Skelaxin). Not controlled. The FDA’s drug labeling lists no DEA schedule.
No muscle relaxant of any kind is sold over the counter in the United States. Even the unscheduled ones require a valid prescription.
One point worth remembering: a drug being unscheduled today does not lock in that status. Either the DEA or the Department of Health and Human Services can start the process of adding a drug to the schedules, and any interested party can petition for a change.3United States Drug Enforcement Administration. The Controlled Substances Act Carisoprodol was unscheduled for decades before 2012.
What Schedule IV Status Means at the Pharmacy
For carisoprodol and diazepam, federal law constrains how prescriptions are written and refilled. A Schedule IV prescription cannot be filled or refilled more than six months after it was written, and you cannot get more than five refills before your doctor must write a new one.4Office of the Law Revision Counsel. 21 USC 829: Prescriptions After five refills or six months, whichever comes first, you need a fresh prescription.
The prescription itself must include the date of issuance, your full name and address, and the prescribing practitioner’s name, address, and DEA registration number.5eCFR. 21 CFR Part 1306 – Controlled Substances Listed in Schedules III, IV, and V Missing elements can delay the fill.
Telehealth Prescriptions Through 2026
The Ryan Haight Act normally requires an in-person medical evaluation before a provider can prescribe a controlled substance. A pandemic-era flexibility has been extended several times. DEA-registered practitioners can currently prescribe Schedule II through V controlled substances via telehealth without an in-person visit, provided the prescription is for a legitimate medical purpose and issued through a live audio-video consultation. The authorization runs through December 31, 2026.6Federal Register. Fourth Temporary Extension of COVID-19 Telemedicine Flexibilities for Prescription of Controlled Medications If it isn’t renewed, patients receiving carisoprodol or diazepam by telehealth will need an in-person evaluation before their next prescription.
Penalties for Possessing Someone Else’s Pills
Possessing a controlled muscle relaxer without a valid prescription is a federal crime. A first offense of simple possession carries up to one year in prison and a minimum fine of $1,000.7Office of the Law Revision Counsel. 21 USC 844: Penalties for Simple Possession Second and later convictions carry steeper penalties. State charges can stack on top.
The practical risk most people run into is not a federal prosecution but a state charge after a traffic stop or an unrelated arrest. A few leftover Soma pills from a friend in your bag meets the legal definition of unauthorized possession.
Where States Go Further Than Federal Law
Federal scheduling sets the floor, not the ceiling. States can place a drug on a stricter schedule than the federal government does, or schedule a drug the federal government leaves alone entirely.8NCBI Bookshelf. State Laws and Regulations – Development of Medications for the Treatment of Opiate and Cocaine Addictions A handful of states have classified cyclobenzaprine as a controlled substance despite its unscheduled federal status, so possessing it without a prescription in those states carries criminal penalties it wouldn’t carry elsewhere.
Many states also require pharmacies to report dispensing data to a Prescription Drug Monitoring Program (PDMP), even for drugs that aren’t controlled. Gabapentin is a common example, and some PDMP rules flag combinations of gabapentin with muscle relaxers or opioids. If your state’s PDMP tracks a medication you take, your prescriber and pharmacist can see your fill history across participating pharmacies.
You Can Still Get a DUI on a Non-Controlled Muscle Relaxer
This one catches people. Most state impaired-driving laws aren’t limited to alcohol or illegal drugs. They target impairment from any substance, including lawfully prescribed ones. If an officer observes drowsiness, slowed reactions, or poor coordination and a field sobriety test confirms impairment, the fact that you have a valid prescription is not a defense to the DUI itself.
The FDA lists muscle relaxants among the medication categories that can make driving dangerous, pointing to side effects like drowsiness, blurred vision, dizziness, and slowed movement.9U.S. Food and Drug Administration. Some Medicines and Driving Don’t Mix Cyclobenzaprine in particular is known for dulling coordination. A DUI conviction involving a prescription muscle relaxer carries the same license suspensions, fines, and potential jail time as an alcohol-related DUI. If your label warns against driving, take the warning seriously.
Muscle Relaxers and Drug Tests
Standard 5-panel and 10-panel employment drug screens look for opioids, amphetamines, benzodiazepines, cocaine, and marijuana. Most muscle relaxers do not show up because the tests aren’t looking for them.
Carisoprodol is the exception. Because the body metabolizes it into meprobamate, a carisoprodol user can test positive if the panel includes meprobamate or if a broader toxicology screen is ordered. Diazepam will show up on any panel that tests for benzodiazepines. Cyclobenzaprine, methocarbamol, tizanidine, and baclofen are not typically detected on standard panels; an employer or probation officer would need to request a specialized test. If you’re subject to workplace testing, keep your prescription documentation accessible for a medical review officer.
Stopping a Non-Controlled Muscle Relaxer Can Still Be Dangerous
“Not scheduled” and “safe to quit cold turkey” are two different things. Baclofen is the starkest example. Abrupt cessation, whether of the oral form or an intrathecal pump, can trigger a withdrawal syndrome with agitation, hallucinations, seizures, confusion, psychosis, hyperthermia, and increased spasticity. Severe cases are life-threatening.10NCBI (National Center for Biotechnology Information). Oral Baclofen Withdrawal Resulting in Progressive Weakness and Sedation
Tizanidine can produce rebound hypertension and increased spasticity if discontinued suddenly after prolonged use. Taper off any muscle relaxer under your doctor’s guidance, controlled or not.
Traveling With Controlled Muscle Relaxers
If you travel with carisoprodol, diazepam, or any other controlled medication, U.S. Customs and Border Protection requires travelers to declare controlled medications to a CBP officer, carry them in the original pharmacy-labeled container, bring only the quantity a person with your condition would normally need, and carry a prescription or written statement from the doctor confirming medical necessity.11U.S. Customs and Border Protection. Traveling with Medication
For domestic flights, TSA does not prohibit prescription medications, but keeping controlled substances in their original labeled bottles avoids delays. For international travel, check the destination country’s rules. Some countries ban substances that are legal in the United States, and arriving with them can result in arrest regardless of your American prescription.