Muscle relaxants relax certain muscles in the body and are prescribed for sprains, strains and other muscle injuries that cause pain, stiffness or muscle spasms. Muscle relaxants are available by prescription only in the United States, although some kinds can be purchased in Canada without a prescription. Most muscle relaxants come in tablet form, but some come in the form of injections as well. Muscle relaxants are extremely effective for alleviating pain due to injuries, but they are not effective for any other type of pain relief. Therefore, they should only be taken for specific injuries as prescribed by a doctor.

Muscle relaxants work directly on the central nervous system. As a result they may increase the effects of alcohol and other drugs that slow down the central nervous system such as antihistamines, cold medicine, allergy medicine, sleep aids, medicine for seizures, tranquilizers, some pain relievers, and other muscle relaxants. Therefore, when taking this kind of medicine patients should ask their doctor about any other medications they may take, even over the counter ones.

It is important that patients realize that muscle relaxants should be taken in conjunction with rest, exercise, physical therapy or other treatments. Patients should not consider muscle relaxants a substitution for these other treatments. Because muscle relaxants work so well, they often make patients feel as if they are better even if they are not. Therefore, even if patients feel better, they should wait to resume their regular activities.

Before taking muscle relaxants, patients should make physicians aware of pre-existing conditions such as kidney disease, heart or blood vessel disease, recent heart attacks, irregular heartbeat, overactive thyroid gland, hepatitis, liver disease, current or past alcohol or drug abuse, glaucoma or problems with urination. Muscle relaxants may increase the likelihood of seizures for those with epilepsy.

Side effects cause by muscle relaxants include blurred or double vision, dizziness, drowsiness, dry mouth and lightheadedness. Most of these side effects disappear as patients become more accustomed to the drugs. Muscle relaxants may also cause color changes in urine. Depending on the specific relaxant, it can appear orange, reddish-purple, purple, brown or green. This is harmless and the urine will return to its normal color when the patient stops the medication.