Treatments for back pain: Pharmacological therapy

Treatments Basis, indications and risk Patient information Postural hygiene Exercise Maintaining level of Activity Bed rest Pharmacological therapy Analgesics Non steroideal antiinflammatory drugs Muscle relaxants Other Neuroreflexotherapy (NRT) Spinal column surgery Surgery for Pain and Pain Clinics Vertebral manipulation Behavioral treatment Epidural injections Facet joint infections Trigger point and ligament infections Rhizotomy Corsets and lumbar belts Traction Physical therapy/physiotherapy Electromyografic Feedback TENS: Transcutaneous electrical Nerve Stimulation Shoe insoles and shoe lifts Acupunture Recommended treatments

Muscle relaxants

Objective

To decrease muscle contracture.

Theoretical base

Muscle contracture appears through the activation of one of the different types of nerves that control muscles. When activated, it releases some substances that attach to muscle receptors, which provoke and maintain contracture.

Muscle relaxants inhibit this effect through diverse mechanisms. The main mechanism is that muscle relaxant molecules occupy muscle receptors without provoking a contracture. Through this mechanism, muscle relaxants impede that the substances released by the nerve affix onto the receptor, avoiding their effect.

Evidence of efficacy

Some studies show the efficacy of muscle relaxants for improvement of acute back pain symptoms.

The existing recommendations based on scientific evidence establish that, although frequently prescribed along with anti-inflammatory drugs, their combination has not proven to produce a better effect than each agent taken alone.

Risks

When taking a muscular relaxant orally, by suppository, or by intramuscular injection, it is introduced into the blood and is distributed throughout the body. The portion reaching the structures involved in back pain may cause improvement but the remaining portion is useless and may have side effects.

Side effects are specific to a determined pharmaceutical compound and are detailed in package inserts of pharmaceutical drugs. The most frequent muscle relaxant adverse effects are drowsiness and decreased reaction time. Some of the existing recommendations based on scientific evidence have established that these symptoms appear in about 30% of patients. While taking these pharmaceuticals it is best to avoid risk activities -including vehicle driving- and to abstain from drinking alcoholic beverages, since the association may increase their effects and be very harmful. Abuse of muscle relaxants may cause liver toxicity.

The longer a pharmaceutical drug is used the lesser its efficacy and the greater the risk of onset of adverse effects. Therefore, it is important to avoid self-medicating and the drug should be taken strictly under a physician's prescription. Muscle relaxants have the potential for physical dependence, which may make withdrawal difficult. The risk is greater in prolonged intake periods; some of the existing recommendations based on scientific evidence establish that even after a relatively short period of 1 week dependence can occur.

Drugs that have previously caused allergies must not be used. They can cause harmful effects and even death.

Indications

The use of muscle relaxants should be recommended during episodes of acute pain, or in crises or chronic pain exacerbation.

In general, with exceptions, to decrease the risk of side effects use is recommended for no longer than 14 consecutive days. Some of the existing recommendations based on scientific evidence specifically contraindicate use for a longer period in light of the risk of dependence and habit-forming effects.