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

Cyclobenzaprine Is a Prescription Muscle Relaxant Used to Treat Muscle Spasms

Cyclobenzaprine is a centrally acting skeletal muscle relaxant prescribed to relieve muscle spasms associated with acute, painful musculoskeletal conditions — typically alongside rest and physical therapy. It's one of the most commonly prescribed muscle relaxants in the United States and has been in use for decades. Here's everything you need to know about it in 2026.

What Is Cyclobenzaprine?

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

• Amrix — the extended-release capsule formulation
• Fexmid (discontinued)
• Tonmya — a sublingual formulation approved in 2024 for fibromyalgia

It belongs to the class of centrally acting skeletal muscle relaxants and is structurally related to tricyclic antidepressants like Amitriptyline. However, Cyclobenzaprine is used for muscle relaxation, not depression.

Key Facts at a Glance

• Drug class: Centrally acting skeletal muscle relaxant
• FDA-approved: Yes, for short-term relief of muscle spasm
• Controlled substance: No — Cyclobenzaprine is not scheduled under the DEA's Controlled Substances Act
• Available as generic: Yes, widely available
• Prescription required: Yes

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 2-3 weeks. It is not approved for treating spasticity from neurological conditions like cerebral palsy or multiple sclerosis.

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

Off-label use means a doctor has determined the medication may benefit you even though it's not specifically FDA-approved for that condition.

How Is Cyclobenzaprine Taken?

Cyclobenzaprine comes in two main formulations:

Immediate-Release Tablets

• Available strengths: 5 mg, 7.5 mg, 10 mg
• Typical dose: 5 mg three times daily, may be increased to 10 mg three times daily
• Maximum dose: 30 mg per day
• Can be taken with or without food

Extended-Release Capsules (Amrix)

• Available strengths: 15 mg, 30 mg
• Typical dose: 15 mg once daily; some patients may need 30 mg once daily
• Maximum dose: 30 mg per day
• Do not crush, chew, or open the capsules

Most doctors start patients on the lower dose and increase only if needed. The medication is typically prescribed for no more than 2-3 weeks. To understand how the drug works in your body, read our guide on how Cyclobenzaprine works.

Who Should Not Take Cyclobenzaprine?

Cyclobenzaprine is not appropriate for everyone. You should not take Cyclobenzaprine if you have:

• Hypersensitivity to Cyclobenzaprine or any of its ingredients
• Used an MAO inhibitor within the past 14 days (such as Phenelzine, Tranylcypromine, or Selegiline) — this combination can cause a life-threatening reaction
• Heart conditions including arrhythmias, heart block, conduction disturbances, or heart failure
• Recent heart attack (acute recovery phase of myocardial infarction)
• Hyperthyroidism (overactive thyroid)

Additionally, Cyclobenzaprine requires caution in these populations:

• Adults over 65: Higher risk of side effects; listed on the Beers Criteria as potentially inappropriate
• Children under 15: Not recommended
• People with liver problems: Reduced ability to process the medication; not recommended in moderate-to-severe hepatic impairment
• Pregnant or breastfeeding women: Category B — use only if clearly needed; unknown if excreted in breast milk

Always provide your doctor with a complete medical history and a full list of your medications before starting Cyclobenzaprine. For a detailed look at interactions, see our guide on Cyclobenzaprine drug interactions.

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, blurred vision

Serious but rare side effects include serotonin syndrome, cardiac arrhythmias, seizures, and severe allergic reactions. For a complete breakdown, read our article on Cyclobenzaprine side effects.

How Much Does Cyclobenzaprine Cost?

Cost varies significantly depending on the formulation and whether you use insurance or a discount card:

Generic Immediate-Release Tablets

• Retail price (without insurance): $10-$35 for 30 tablets
• With coupon (GoodRx, SingleCare, etc.): As low as $4-$9 for 30 tablets
• With insurance: Typically Tier 1 (preferred generic) with $0-$15 copay

Generic Extended-Release Capsules

• Retail price: Approximately $1,067 for 30 capsules (15 mg)
• With coupon: Around $54 for 30 capsules
• Insurance: May require prior authorization or step therapy (trying IR first)

For most patients, the generic immediate-release tablets are both effective and affordable. If cost is a concern, check our guide on how to save money on Cyclobenzaprine and use Medfinder to compare prices at pharmacies near you.

Final Thoughts

Cyclobenzaprine is a well-established, affordable muscle relaxant that works well for short-term relief of muscle spasms when combined with rest and physical therapy. It's not a controlled substance, making it easier to prescribe and access — including through telehealth visits. While most people tolerate it well, it's important to understand the side effects, drug interactions, and who should avoid it.

If you have a prescription for Cyclobenzaprine and need to find it at a pharmacy, search Medfinder to check availability and pricing near you.