SKELETALMUSCLE RELAXANTS (Systemic)
Some commonly used brand names are:
In the U.S.?
- EZE-DS 3
- Maolate 2
- Paraflex 3
- Parafon Forte DSC 3
- Relaxazone 3
- Remular 3
- Remular-S 3
- Robaxin 5
- Robaxin-750 5
- Skelaxin 4
- Soma 1
- Strifon Forte DSC 3
- Vanadom 1
In Canada?
- Robaxin 5
- Robaxin-750 5
- Soma 1
Note: | For quick reference, the following skeletal muscle relaxants arenumbered to match the corresponding brand names. |
Category
- Skeletal muscle relaxant?Carisoprodol; Chlorphenesin; Chlorzoxazone; Metaxalone; Methocarbamol
Description
Skeletalmuscle relaxants are used to relax certain muscles in your body and relievethe stiffness, pain, and discomfort caused by strains, sprains, or other injuryto your muscles. However, these medicines do not take the place of rest, exerciseor physical therapy, or other treatment that your doctor may recommend foryour medical problem. Methocarbamol also has been used to relieve some ofthe muscle problems caused by tetanus.
Skeletal muscle relaxants act in the central nervous system (CNS) to producetheir muscle relaxant effects. Their actions in the CNS may also produce someof their side effects.
In the U.S., these medicines are available only with your doctor's prescription.In Canada, some of these medicines are available without a prescription.
These medicines are available in the following dosage forms:
Oral- Carisoprodol
- Tablets (U.S. and Canada)
- Chlorphenesin
- Chlorzoxazone
- Metaxalone
- Methocarbamol
- Tablets (U.S. and Canada)
Parenteral- Methocarbamol
- Injection (U.S. and Canada)
Before Using This Medicine
In deciding to use a medicine,the risks of taking the medicine must be weighed against the good it willdo. This is a decision you and your doctor will make. For the skeletal musclerelaxants, the following should be considered:
Allergies?Tell your doctor if you have ever had any unusual orallergic reaction to any of the skeletal muscle relaxants or to carbromal,mebutamate, meprobamate (e.g., Equanil), or tybamate. Also tell your healthcare professional if you are allergic to any other substances, such as foods,preservatives, or dyes.
Pregnancy?Although skeletal muscle relaxants have not beenshown to cause birth defects or other problems, studies on birth defects havenot been done in pregnant women. Studies in animals with metaxalone have notshown that it causes birth defects.
Breast-feeding?Carisoprodol passes into the breast milk and maycause drowsiness or stomach upset in nursing babies. It is not known whetherchlorphenesin, chlorzoxazone, metaxalone, or methocarbamol passes into thebreast milk. However, these medicines have not been reported to cause problemsin nursing babies.
Children?Studies with the skeletal muscle relaxants have beendone only in adult patients, and there is no specific information comparinguse of these medicines in children with use in other age groups. However,carisoprodol and chlorzoxazone have been used in children. They have not beenreported to cause different side effects or problems in children than theydo in adults.
Older adults?Many medicines have not been tested in older people.Therefore, it may not be known whether they work exactly the same way theydo in younger adults or if they cause different side effects or problems inolder people. There is no specific information about the use of skeletal musclerelaxants in the elderly.
Other medicines?Although certain medicines should not be usedtogether at all, in other cases two different medicines may be used togethereven if an interaction might occur. In these cases, your doctor may want tochange the dose, or other precautions may be necessary. When you are takinga skeletal muscle relaxant, it is especially important that your health careprofessional know if you are taking any of the following:
- Alcohol or
- Central nervous system (CNS) depressants or
- Tricyclic antidepressants (amitriptyline [e.g., Elavil], amoxapine[e.g., Asendin], clomipramine [e.g., Anafranil], desipramine [e.g., Pertofrane],doxepin [e.g., Sinequan], imipramine [e.g., Tofranil], nortriptyline [e.g.,Aventyl], protriptyline [e.g., Vivactil], trimipramine [e.g., Surmontil])?Thechance of side effects may be increased
Other medical problems?The presence of other medicalproblems may affect the use of a skeletal muscle relaxant. Make sure you tellyour doctor if you have any other medical problems, especially:
- Allergies, history of, or
- Blood disease caused by an allergy or reaction to any other medicine,history of, or
- Drug abuse or dependence, or history of, or
- Kidney disease or
- Liver disease or
- Porphyria?Depending on which of the skeletal muscle relaxantsyou take, the chance of side effects may be increased; your doctor can choosea muscle relaxant that is less likely to cause problems
- Epilepsy?Convulsions may be more likely to occur if methocarbamolis given by injection
Proper Use of This Medicine
Chlorzoxazone,metaxalone, or methocarbamol tablets may be crushed and mixed with a littlefood or liquid if needed to make the tablets easier to swallow.
Dosing?The dose of these medicines will be differentfor different patients. Follow your doctor's orders orthe directions on the label. The following information includes onlythe average doses of these medicines. If your dose isdifferent, do not change it unless your doctor tells you to do so.
For carisoprodol- For oral dosage form (tablets):
- For relaxing stiff, sore muscles:
- Adults and teenagers?350 milligrams (mg) four times a day.
- Children up to 5 years of age?Dose must be determined by yourdoctor.
- Children 5 to 12 years of age?6.25 mg per kilogram (2.5 mgper pound) of body weight four times a day.
For chlorphenesin- For oral dosage form (tablets):
- For relaxing stiff, sore muscles:
- Adults and teenagers?800 milligrams (mg) three times a day,at first. Your doctor may decrease your dose after you begin to feel better.
- Children?Use and dose must be determined by your doctor.
For chlorzoxazone- For oral dosage form (tablets):
- For relaxing stiff, sore muscles:
- Adults and teenagers?500 milligrams (mg) three or four timesa day.
- Children?125 to 500 mg three or four times a day, dependingon the child's size and weight.
For metaxalone- For oral dosage form (tablets):
- For relaxing stiff, sore muscles:
- Adults and teenagers?800 milligrams (mg) three or four timesa day.
- Children?Use and dose must be determined by your doctor.
For methocarbamol- For oral dosage form (tablets):
- For relaxing stiff, sore muscles:
- Adults and teenagers?1500 milligrams (mg) four times a day,at first. Your doctor may decrease your dose after you begin to feel better.
- Children?Use and dose must be determined by your doctor.
- For injection dosage form:
- For relaxing stiff, sore muscles:
- Adults and teenagers?1 to 3 grams a day, injected into a muscleor a vein. This total daily dose may be divided into smaller amounts thatare given several times a day, especially when the medicine is injected intoa muscle.
- Children?Use and dose must be determined by your doctor.
Missed dose?If you miss a dose of this medicine and rememberwithin an hour or so of the missed dose, take it right away. But if you donot remember until later, skip the missed dose and go back to your regulardosing schedule. Do not double doses.
Storage?To store this medicine:
- Keep out of the reach of children.
- Store away from heat and direct light.
- Do not store this medicine in the bathroom, near the kitchen sink,or in other damp places. Heat or moisture may cause the medicine to breakdown.
- Do not keep outdated medicine or medicine no longer needed. Be surethat any discarded medicine is out of the reach of children.
Precautions While Using This Medicine
If youwill be taking this medicine for a long time (for example, more than a fewweeks), your doctor should check your progress at regular visits.
This medicine will add to the effects of alcohol and other CNS depressants(medicines that slow down the nervous system, possibly causing drowsiness).Some examples of CNS depressants are antihistamines or medicine for hay fever,other allergies, or colds; sedatives, tranquilizers, or sleeping medicine;prescription pain medicine or narcotics; barbiturates; medicine for seizures;other muscle relaxants; or anesthetics, including some dental anesthetics. Do not drink alcoholic beverages, and check with yourdoctor before taking any of the medicines listed above, while you are usingthis medicine.
Skeletal muscle relaxants may cause blurred vision or clumsiness or unsteadinessin some people. They may also cause some people to feel drowsy, dizzy, lightheaded,faint, or less alert than they are normally. Make sureyou know how you react to this medicine before you drive, use machines, ordo anything else that could be dangerous if you are dizzy or are not alert,well-coordinated, and able to see well.
For diabetic patients:
- Metaxalone (e.g., Skelaxin) may cause false test results with onetype of test for sugar in your urine. If your urine sugar test shows an unusuallylarge amount of sugar, or if you have any questions about this, check withyour health care professional. This is especially important if your diabetesis not well controlled.
Side Effects of This Medicine
Along with its needed effects, a medicine may cause some unwanted effects.Although not all of these side effects may occur, if they do occur they mayneed medical attention.
Check with your doctor as soon as possible if any of the following sideeffects occur:
Less common
Fainting; fast heartbeat; fever; hive-like swellings (large) onface, eyelids, mouth, lips, and/or tongue; mentaldepression; shortness of breath, troubled breathing,tightness in chest, and/or wheezing; skin rash, hives,itching, or redness; slow heartbeat (methocarbamolinjection only); stinging or burning of eyes; stuffy nose and red or bloodshot eyes
Rare
Blood in urine; bloody or black, tarrystools; convulsions (seizures) (methocarbamol injectiononly); cough or hoarseness; fast or irregular breathing; lower back or side pain; muscle cramps or pain (not present before treatmentor more painful than before treatment); painful ordifficult urination; pain, tenderness, heat, redness,or swelling over a blood vessel (vein) in arm or leg (methocarbamol injectiononly); pinpoint red spots on skin; puffiness or swelling of the eyelids or around the eyes; sores, ulcers, or white spots on lips or in mouth; sore throat and fever with or without chills; swollenand/or painful glands; unusual bruising or bleeding; unusual tiredness or weakness; vomiting of blood or material that looks like coffee grounds; yellow eyes or skin
Other side effects may occur that usually donot need medical attention. These side effects may go away during treatmentas your body adjusts to the medicine. However, check with your doctor if anyof the following side effects continue or are bothersome:
Less common or rare
Abdominal or stomach cramps or pain; clumsiness or unsteadiness; confusion; constipation; diarrhea; excitement, nervousness, restlessness, or irritability; flushing or redness of face; headache; heartburn; hiccups; muscle weakness; nausea or vomiting; pain or peeling of skin at place of injection (methocarbamolonly); trembling; troublein sleeping; uncontrolled movements of eyes (methocarbamolinjection only)
Although not all of theside effects listed above have been reported for all of these medicines, theyhave been reported for at least one of them. However, since all of these skeletalmuscle relaxants have similar effects, it is possible that any of the aboveside effects may occur with any of these medicines.
In addition to the other side effects listed above, chlorzoxazone may causeyour urine to turn orange or reddish purple. Methocarbamol may cause yoururine to turn black, brown, or green. This effect is harmless and will goaway when you stop taking the medicine. However, if you have any questionsabout this, check with your doctor.
Other side effects not listed above may also occur insome patients. If you notice any other effects, check with your doctor.
Revised: 11/02/2004
