Cyclobenzaprine (Flexeril) Side Effects, Alcohol Interactions & Dosage

What is cyclobenzaprine (Amrix, Fexmid, Flexeril)?

Cyclobenzaprine is a muscle relaxant. Cyclobenzaprine relieves muscle spasm when the spasm is due to local problems, that is, in the muscle itself and not in the nerves controlling the muscles. Cyclobenzaprine has no effect on muscle function. Cyclobenzaprine seems to accomplish its beneficial effect through a complex mechanism within the nervous system, probably in the brainstem.

What are the uses for cyclobenzaprine?

Cyclobenzaprine is used with rest and physical therapy for short-term relief of muscle spasms associated with acute painful muscle and skeletal conditions. It is only for short-term use, up to two or three weeks.

What are the side effects of cyclobenzaprine?

The most common side effects of cyclobenzaprine include:

• Drowsiness
• Dry mouth
• Fatigue
• Headaches
• Dizziness

Other reported side effects include:

• Nausea
• Constipation
• Blurred vision,
• Unpleasant taste
• Nervousness
• Confusion
• Acid reflux
• Abdominal pain or discomfort

Possible serious side effects include:

• Seizures
• Abnormal heart beats
• Stroke
• Heart attacks
• Heat stroke

Abrupt cessation after prolonged therapy may cause withdrawal symptoms such as headaches, nausea, and weakness.

What is the dosage for cyclobenzaprine?

• The recommended dose of cyclobenzaprine dose is 5 or 10 mg three times daily using immediate release tablets or 15 or 30 mg once daily using extended release tablets.

Which drugs or supplements interact with cyclobenzaprine?

• Cyclobenzaprine is chemically related to the tricyclic class of antidepressants, for example, amitriptyline (Elavil, Endep), nortriptyline Pamelor). As such, it should not be taken with or within two weeks of any monoamine oxidase (MAO) inhibitor, for example, isocarboxazid (Marplan), phenelzine (Nardil), tranylcypromine (Parnate), and procarbazine (Matulane). High fever, convulsions, and even death can occur when these drugs are used together.
• Cyclobenzaprine interacts with other medications and drugs that slow the brain's processes, such as
  • alcohol,
  • barbiturates,
  • benzodiazepines, for example, diazepam (Valium), lorazepam (Ativan), and
  • narcotics.

Medically speaking, the term “myalgia” refers to what type of pain?
See Answer

Is cyclobenzaprine safe to use during pregnancy or while breastfeeding?

• There are no adequate studies of cyclobenzaprine in pregnant women. However, studies in animals suggest no important effects on the fetus. Cyclobenzaprine therefore can be used in pregnancy if the physician feels that it is necessary.
• It is not known whether cyclobenzaprine is secreted in milk. However, since it is related to the tricyclic antidepressants, some of which are excreted in breast milk, caution is advised in using this medication in women who are breastfeeding.

What else should I know about cyclobenzaprine?

Cyclobenzaprine:

• Is available in generic form. You need a prescription for this drug.
• Is available as Tablets: 5 and 10 mg. and Capsules (Extended Release): 15 and 30 mg.
• Tablets should be stored between 15 C and 30 C (59 F and 86 F).
• Was approved by the FDA in August 1977