Flexeril is a muscle relaxant. It works by blocking nerve impulses (or pain sensations) that are sent to your brain.
Take Flexeril exactly as directed by your doctor. If you do not understand these instructions, ask your pharmacist, nurse, or doctor to explain them to you. Take each dose with a full glass of water. Flexeril is usually taken several times a day. Follow your doctor's instructions. You should begin to notice relief from your symptoms after 1 to 2 days of treatment. Do not stop taking Flexeril suddenly if you have been taking it regularly for more than 1 week. Stopping suddenly may cause nausea, headache, and general discomfort.
If you experience any of the following serious side effects, stop taking Flexeril and seek emergency medical attention: an allergic reaction (difficulty breathing; closing of your throat; swelling of your lips, tongue, or face; or hives); seizures, hallucinations, or confusion; blurred vision; increased heart rate; or depression. Other, less serious side effects may be more likely to occur.
Continue to take Flexeril and talk to your doctor if you experience drowsiness or dizziness; dry mouth or a bad taste in your mouth; insomnia; difficulty urinating; or sweating.
If you stop taking this medication suddenly, you may experience some withdrawal effects. Side effects other than those listed here may also occur. Talk to your doctor about any side effect that seems unusual or that is especially bothersome.
Use caution when driving, operating machinery, or performing other hazardous activities. Flexeril may cause dizziness or drowsiness. If you experience dizziness or drowsiness, avoid these activities.
Use alcohol cautiously. Alcohol may increase drowsiness and dizziness while you are taking Flexeril.
Do not take Flexeril if you have taken a monoamine oxidase inhibitor (MAOI) such as isocarboxazid (Marplan), phenelzine (Nardil), or tranylcypromine (Parnate) in the last 14 days. Dangerous side effects could result.
Many drugs can increase drowsiness associated with Flexeril: antihistamines such as brompheniramine, chlorpheniramine, azatadine, clemastine;
narcotics (pain killers) such as meperidine, morphine, propoxyphene, hydrocodone, oxycodone, fentanyl, and codeine;
sedatives such as phenobarbital, amobarbital, and secobarbital;
phenothiazines such as chlorpromazine, fluphenazine, mesoridazine, perphenazine, prochlorperazine, thioridazine, and trifluoperazine;
antidepressants such as doxepin, imipramine, nortriptyline, fluoxetine, paroxetine, sertraline, phenelzine, and tranylcypromine.
Do not take any of the drugs listed above without the approval of your doctor.
The stomach medicine cimetidine (Tagamet, Tagamet HB) and pain relievers such as aspirin, ibuprofen (Motrin, Advil), indomethacin (Indocin), ketoprofen (Orudis, Orudis KT, Oruvail), fenoprofen (Nalfon), flurbiprofen (Ansaid), naproxen (Aleve, Anaprox, Naprosyn), and nabumetone (Relafen) may all increase the pain-relieving effects of Flexeril. Use these drugs under the supervision of your doctor.
Drugs other than those listed here may also interact with Flexeril. Talk to your doctor and pharmacist before taking any prescription or over-the-counter medicines.
If you take too much:
Seek emergency medical attention. Symptoms of a Flexeril overdose include drowsiness, seizures, irregular heartbeats, hallucinations, and difficulty breathing.
Take the missed dose as soon as you remember. However, if it is almost time for your next dose, skip the dose you missed and take your next regularly scheduled dose. Do not take a double dose of this medication.
Store Flexeril at room temperature in a tightly-closed container, away from heat and light.