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

What Is Cyclobenzaprine?

Cyclobenzaprine is a prescription muscle relaxant that has been used in the United States since the 1970s. It's one of the most commonly prescribed medications for short-term relief of muscle spasms caused by injuries, strains, and other acute musculoskeletal conditions.

You might recognize Cyclobenzaprine by its former brand name, Flexeril, which has been discontinued but is still widely referenced. The extended-release version is sold under the brand name Amrix. Today, most prescriptions are filled with the affordable generic version.

Cyclobenzaprine belongs to the class of medications known as skeletal muscle relaxants. Interestingly, its chemical structure is closely related to tricyclic antidepressants like amitriptyline, which explains some of its effects and side effects.

What Is Cyclobenzaprine Used For?

FDA-Approved Use

Cyclobenzaprine is FDA-approved as an adjunct to rest and physical therapy for the short-term treatment (2-3 weeks) of muscle spasms associated with acute, painful musculoskeletal conditions. This includes:

• Back strains and sprains
• Neck pain from muscle tension
• Muscle spasms from injuries
• Post-surgical muscle tightness
• Acute musculoskeletal pain

It's important to understand that Cyclobenzaprine is meant to be part of a broader treatment plan that includes rest, physical therapy, and other measures — not a standalone solution.

Off-Label Uses

Some doctors prescribe Cyclobenzaprine for conditions not listed on the FDA label. Common off-label uses include:

• Fibromyalgia — Low-dose Cyclobenzaprine at bedtime may help improve sleep quality in fibromyalgia patients
• Myofascial pain from TMJ disorders — May help relax jaw muscles
• Chronic low back pain — Sometimes used beyond the typical 2-3 week window
• Tension headaches — When related to muscle tension in the neck and shoulders

How Does Cyclobenzaprine Work?

Cyclobenzaprine works in the brain and spinal cord — not directly on your muscles. It acts primarily in the brainstem to reduce signals that cause muscles to tense up and spasm. By decreasing tonic somatic motor activity, it helps your muscles relax without affecting your ability to move them voluntarily.

For a more detailed explanation, check out our guide on how Cyclobenzaprine works.

Dosage and How to Take It

Immediate-Release Tablets

The immediate-release form is the most commonly prescribed version:

• Starting dose: 5 mg three times daily
• Typical dose: 5 mg to 10 mg three times daily
• Maximum dose: 30 mg per day
• Available strengths: 5 mg, 7.5 mg, and 10 mg tablets

Extended-Release Capsules (Amrix)

The extended-release version is taken less frequently:

• Typical dose: 15 mg once daily
• Maximum dose: 30 mg once daily
• Available strengths: 15 mg and 30 mg capsules

Important Dosing Guidelines

• Take with or without food
• Do not crush, chew, or open extended-release capsules
• Treatment is usually limited to 2-3 weeks
• Your doctor may start with a lower dose and increase it based on your response
• Older adults typically start at the lowest dose (5 mg) and may not need increases

Is Cyclobenzaprine a Controlled Substance?

No. Cyclobenzaprine is not classified as a controlled substance by the DEA. This means:

• It doesn't require a special prescription pad
• Refills are easier to obtain
• It can be prescribed via telehealth in most states
• There are no DEA quantity limits

That said, Cyclobenzaprine does have some potential for misuse due to its sedating effects, so it's important to take it only as prescribed.

Common Side Effects

Most side effects are mild and temporary. The most common include:

• Drowsiness (up to 39% of users) — the most reported side effect
• Dry mouth (up to 32%) — drink plenty of water
• Dizziness (about 11%) — stand up slowly
• Fatigue
• Constipation
• Nausea
• Headache

For a complete guide to managing side effects, read our article on Cyclobenzaprine side effects.

Who Should Not Take Cyclobenzaprine?

Cyclobenzaprine is not right for everyone. You should not take it if you:

• Have taken an MAO inhibitor within the last 14 days
• Have certain heart conditions (arrhythmias, heart block, heart failure)
• Have recently had a heart attack
• Have hyperthyroidism (overactive thyroid)
• Are allergic to Cyclobenzaprine or tricyclic antidepressants

Use with caution if you:

• Are over 65 years old
• Have liver disease
• Take other medications that cause drowsiness
• Take serotonergic medications (SSRIs, SNRIs)

Always tell your doctor about all medications you take. Learn more about Cyclobenzaprine drug interactions.

How Much Does Cyclobenzaprine Cost?

One of the best things about Cyclobenzaprine is that it's very affordable as a generic:

• Generic IR tablets: $10-$35 retail for a 30-day supply; as low as $4-$9 with discount coupons
• Generic ER capsules: Much more expensive — around $50-$1,000+ depending on the pharmacy and whether you use coupons
• With insurance: Most plans cover generic Cyclobenzaprine IR at the lowest copay tier ($0-$15)

Discount cards from GoodRx, SingleCare, and other providers can bring the price down significantly. For more savings tips, check out our guide on how to save money on Cyclobenzaprine.

Alternatives to Cyclobenzaprine

If Cyclobenzaprine isn't right for you — whether because of side effects, drug interactions, or availability — there are several alternatives your doctor might consider:

• Methocarbamol (Robaxin) — May cause less drowsiness
• Tizanidine (Zanaflex) — Works differently; may be better for certain types of spasticity
• Baclofen — Often used for spasticity from neurological conditions
• Metaxalone (Skelaxin) — Generally well-tolerated with fewer sedating effects

Read our full guide on Cyclobenzaprine alternatives for more information.

The Bottom Line

Cyclobenzaprine is a safe, effective, and affordable muscle relaxant that's been helping people manage muscle spasms for over 40 years. It's available as a low-cost generic, can be prescribed through telehealth, and is covered by most insurance plans. While it comes with side effects — particularly drowsiness — most people tolerate it well for short-term use.

If you need help finding Cyclobenzaprine or a provider who can prescribe it, visit Medfinder to search pharmacies and doctors near you.