Cyclobenzaprine vs. Norco (hydrocodone acetaminophen)

• Cyclobenzaprine and Norco (hydrocodone acetaminophen) are used to treat pain.
• Cyclobenzaprine is mainly used with rest and physical therapy for short-term relief of muscle spasms associated with acute painful muscle and skeletal conditions.
• Norco is prescribed for moderate to moderately severe pain of various causes.
• Brand names for cyclobenzaprine include Flexeril, Amrix, and Fexmid.
• Cyclobenzaprine and Norco belong to different drug classes. Cyclobenzaprine is a muscle relaxant and Norco is a combination of a narcotic pain reliever and a cough suppressant, and a non-narcotic analgesic (pain reliever) and antipyretic (fever reducer).
• Side effects of cyclobenzaprine and Norco that are similar include dizziness, drowsiness, nausea, and constipation.
• Side effects of cyclobenzaprine that are different from Norco include dry mouth, fatigue, headaches, blurred vision, unpleasant taste, nervousness, confusion, acid reflux, and abdominal pain or discomfort.
• Side effects of Norco that are different from cyclobenzaprine include lightheadedness, sedation, vomiting, and difficulty urinating.
• Withdrawal symptoms may occur if you suddenly stop using Norco.

Cyclobenzaprine is a muscle relaxant used with rest and physical therapy for short-term relief up to two or three weeks only of muscle spasms associated with acute painful muscle and skeletal conditions. Cyclobenzaprine relieves muscle spasm when the spasm is due to problems in the muscle itself and not problems in the nerves controlling the muscles. Cyclobenzaprine seems to achieve its helpful effect through a complex mechanism within the nervous system, probably in the brainstem.

Norco (hydrocodone acetaminophen) is a combination of a narcotic pain-reliever and a cough suppressant, similar to codeine, and a non-narcotic analgesic (pain reliever) and antipyretic (fever reducer) prescribed for moderate to moderately severe pain. The hydrocodone in Norco blocks the receptors on nerve cells in the brain that give rise to the sensation of pain. The acetaminophen in Norco works by elevating the threshold to pain, that is, in order for pain to be felt, greater stimulation of the nerves responsible for the sensation of pain is necessary. It reduces fever through its action on the temperature-regulating center of the brain.

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.

Norco

Common side effects of hydrocodone/acetaminophen are:

• lightheadedness,
• dizziness,
• sedation,
• nausea, and
• vomiting.

Other important side effects include:

• drowsiness,
• constipation, and
• spasm of the ureter, which can lead to difficulty in urinating.

Hydrocodone can impair thinking and the physical abilities required for driving or operating machinery. Hydrocodone can depress breathing, and should be used with caution in elderly, debilitated patients and in patients with serious lung disease.

Hydrocodone may be habit-forming. Mental and physical dependence can occur but are unlikely when used for short-term pain relief.

Acetaminophen can cause severe liver failure if excessive amounts are used and when combined with chronic alcohol use or other drugs that also impair liver function.

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.

Norco

The usual dose for adults is 1 to 2 tablets or capsules (hydrocodone 2.5 to 10 mg; acetaminophen 300 to 750 mg) every 4 to 6 hours or 15 mL of liquid every 4 to 6 hours as needed.

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.

Norco

Patients receiving other narcotics, antihistamines, antipsychotics, antianxiety agents, or other CNS depressants (including alcohol) concomitantly with NORCO may exhibit an additive CNS depression. When combined therapy is contemplated, the dose of one or both agents should be reduced.

The use of MAO inhibitors or tricyclic antidepressants with hydrocodone preparations may increase the effect of either the antidepressant or hydrocodone.

Drug/Laboratory Test Interactions

Acetaminophen may produce false-positive test results for urinary 5-hydroxyindoleacetic acid.

Cyclobenzaprine

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.

Norco

There are no adequate studies of hydrocodone and acetaminophen in pregnant women.

Hydrocodone/acetaminophen is excreted in breast milk, and, therefore should be used cautiously by nursing mothers.