What Is Cyclobenzaprine? Uses, Dosage, and What You Need to Know in 2026

Cyclobenzaprine Is a Prescription Muscle Relaxant Used to Treat Painful Muscle Spasms

Cyclobenzaprine is a centrally acting skeletal muscle relaxant prescribed to relieve muscle spasms associated with acute, painful musculoskeletal conditions like back injuries, neck strains, and sprains. It's one of the most commonly prescribed muscle relaxants in the United States and has been available since the late 1970s.

Whether you've just been prescribed Cyclobenzaprine or you're researching it before talking to your doctor, this guide covers everything you need to know — from how it works to how much it costs in 2026.

What Is Cyclobenzaprine?

Cyclobenzaprine is the generic name for a muscle relaxant originally sold under the brand name Flexeril (now discontinued). Other brand names include:

• Amrix — An extended-release capsule formulation
• Fexmid — A discontinued tablet formulation
• Tonmya — A sublingual formulation approved in 2024 for fibromyalgia

Cyclobenzaprine belongs to the class of centrally acting skeletal muscle relaxants. Interestingly, it is structurally very similar to the tricyclic antidepressant Amitriptyline (Elavil), which explains some of its side effects and drug interactions.

Important: Cyclobenzaprine is not a controlled substance. It is not classified under the Controlled Substances Act and does not carry the prescribing restrictions that apply to medications like opioids or benzodiazepines.

What Is Cyclobenzaprine Used For?

FDA-Approved Use

Cyclobenzaprine is FDA-approved as an adjunct to rest and physical therapy for the relief of muscle spasm associated with acute, painful musculoskeletal conditions. It's intended for short-term use only — typically 2 to 3 weeks.

Common conditions it's prescribed for include:

• Acute back pain with muscle spasms
• Neck pain and stiffness
• Muscle strains and sprains
• Musculoskeletal injuries

Off-Label Uses

Doctors sometimes prescribe Cyclobenzaprine off-label for:

• Fibromyalgia — Particularly for improving sleep quality and reducing pain
• Myofascial pain from temporomandibular disorders (TMJ)
• Chronic low back pain
• Tension headaches

How Is Cyclobenzaprine Taken?

Cyclobenzaprine comes in two main formulations:

Immediate-Release Tablets

• Available strengths: 5 mg, 7.5 mg, and 10 mg
• Typical dose: 5 mg three times daily, which may be increased to 10 mg three times daily based on your response
• Maximum dose: 30 mg per day
• How to take: With or without food, usually three times a day

Extended-Release Capsules (Amrix)

• Available strengths: 15 mg and 30 mg
• Typical dose: 15 mg once daily; some patients may need 30 mg once daily
• Maximum dose: 30 mg per day
• How to take: Once daily at the same time each day. Do not crush, chew, or open the capsule.

Duration: Cyclobenzaprine is designed for short-term use — generally no more than 2 to 3 weeks. Your doctor will let you know when it's time to stop.

Who Should Not Take Cyclobenzaprine?

Cyclobenzaprine is not safe for everyone. You should not take this medication if you have:

• Taken an MAO inhibitor within the past 14 days (including Isocarboxazid, Phenelzine, Tranylcypromine, Selegiline, or Linezolid) — this combination can cause a life-threatening reaction
• Heart problems including arrhythmias, heart block, conduction disturbances, or heart failure
• Recent heart attack — Cyclobenzaprine should not be used during the acute recovery phase
• Hyperthyroidism (overactive thyroid)
• Known allergy to Cyclobenzaprine

Use with caution if you:

• Are over 65 years old (listed on the Beers Criteria as potentially inappropriate for older adults)
• Have liver disease (start at a lower dose; avoid with moderate-to-severe impairment)
• Are pregnant or breastfeeding (Category B — discuss with your doctor)
• Are under 15 years old (not recommended)

For a detailed look at medications to avoid while taking Cyclobenzaprine, see our drug interactions guide.

What Are the Side Effects?

The most common side effects include:

• Drowsiness (up to 39% of patients)
• Dry mouth (up to 32%)
• Dizziness (up to 11%)
• Fatigue, constipation, nausea, headache, and blurred vision

Serious but rare side effects include serotonin syndrome, cardiac arrhythmias, seizures, and severe allergic reactions. For the full breakdown, including how to manage side effects and when to call your doctor, read our complete Cyclobenzaprine side effects guide.

How Much Does Cyclobenzaprine Cost?

The cost varies significantly depending on which formulation you need and whether you have insurance:

Generic Immediate-Release Tablets

• Without insurance or coupons: $10–$35 for 30 tablets (5 mg or 10 mg)
• With a coupon (GoodRx, SingleCare, etc.): As low as $4–$9 for 30 tablets
• With insurance: Typically Tier 1 (preferred generic) with copays of $0–$15

Generic Extended-Release Capsules

• Without insurance: Average retail around $1,067 for 30 capsules (15 mg)
• With a coupon: Around $54 for 30 capsules
• With insurance: May require prior authorization or step therapy (your insurer may want you to try immediate-release first)

For the best ways to save, check out our guide on Cyclobenzaprine coupons, discounts, and patient assistance programs.

How Does Cyclobenzaprine Compare to Other Muscle Relaxants?

If Cyclobenzaprine isn't right for you — or you can't find it in stock — there are several alternatives:

• Methocarbamol (Robaxin) — Less sedating; similar effectiveness for acute musculoskeletal conditions
• Tizanidine (Zanaflex) — May cause less drowsiness but more dry mouth; also used for spasticity
• Baclofen (Lioresal) — Primarily used for spasticity from conditions like MS or spinal cord injury
• Metaxalone (Skelaxin) — May cause less sedation; generally more expensive

Read our full comparison in alternatives to Cyclobenzaprine.

Final Thoughts

Cyclobenzaprine is a well-established, effective muscle relaxant that's been used for decades. The generic immediate-release version is affordable and widely available, though you may occasionally encounter stock issues. It's best used as a short-term tool alongside rest and physical therapy — not as a long-term solution.

If you're trying to fill a Cyclobenzaprine prescription, Medfinder can help you find a pharmacy near you that has it in stock. And if you want to understand how Cyclobenzaprine works in your body, we've got a plain-English explainer for that too.