Medications for chronic back pain
Medications are frequently prescribed for back pain. Again, it is important to remember that there is no one best medicine for back pain, despite what your friends and relatives tell you. Rational use of medication depends on a diagnosis of the cause of the pain. Medications for nerve irritation will not work for joint pain, and vice versa. The most common medications used for back pain include anti-infammatory medications, muscle relaxants, medications for pain coming from injured nerves (anticonvulsants, antidepressants, and others), and analgesics (non-specific pain medications). The choice of a medication is based on which group is most appropriate for a given diagnosis, and which member of the group is most appropriate for the individual. Often the process involves trials of different medications to judge the patient's therapeutic response and tolerance.

Anti-inflammatory medications
Nonsteroidal anti-inflammatory drugs (NSAIDS) are probably the most commonly prescribed medications for back pain. They reduce inflammation in the body by interfering with the production of a group of chemicals called prostaglandins. The rationale is based upon the concept that much of the pain experienced is due to inflammatory processes which have run amok and are no longer serving any useful purpose. In addition to the anti-inflammatory action of these drugs, they all have a non-specific analgesic effect similar to acetaminophen, (Tylenol). They all have similar side effects related to the fact that some of the prostaglandins in the body serve a useful function, like protecting the stomach from acid and regulating blood flow in the kidney. Thus, common side effects include stomach irritation (including gastritis and ulcers), impaired kidney function and high blood pressure. Common NSAIDS in clinical use include Motrin, Relafen, Naprosyn, Clinoril, and others. Newer NSAIDS are more COX2 selective, reducing side effects due to inhibition of the "good" prostaglandins. These include Mobic, Celebrex, and Bextra.  There is recent evidence, however, that these COX2 selective agents may increase the risk of heart disease and stroke.

Muscle relaxants
Back pain frequently has at least a component of muscle tension or spasm contributing to the symptoms. A cycle develops with muscle tension causing pain which causes more muscle tension. The various medications used for increased muscle tension work at different points in the cycle. Most have drowsiness as the limiting side-effect. Common muscle relaxants include Flexeril, Norflex, Robaxin, Soma, and Baclofen.

Medications for pain coming from injured nerves
Pain can be caused by injury to the nerve fibers in the spinal nerve roots. The mechanism of pain production is complicated, with secondary changes taking place in the spinal cord and brain. Much of the pain seems to be due to spontaneous firing of the injured nerves, with the brain interpreting this firing as pain. There are two main classes of medications used to reduce this firing: the antidepressants and the anticonvulsants. The antidepressants used are the older tricyclic antidepressants such as Elavil and Pamelor. These have an effect on the nerve fibers themselves. When they are effective, they are effective at doses well below the antidepressant level. The anticonvulsants probably work on the nerves themselves as well as having central actions. The most common ones used are Neurontin and Tegretol. In both categories there are numerous other medications with slightly different side effect profiles which can be used if the primary ones are not tolerated or are not fully effective. In addition to these two major groups there are some others which can be effective for some people. Mexital (an oral form of the anesthetic lidocaine) is one member of this miscellaneous group, as are topical preparations like capsaicin creams and topical Lidoderm patches.

Analgesics
These are medications which reduce pain in a non-specific fashion. All of the NSAIDS can be used for this purpose, as well as Tylenol. If these are not strong enough then the next level usually involves medications like Ultram. This is a non-narcotic pain medication, but some people find it hard to stop after regular use without experiencing a withdrawal syndrome. Other medications at this same level include Tylenol with codeine, and Vicodin (Tylenol with hydrocodone). More severe pain may require the use of opioid analgesics. Usually a long-acting agent is taken on a regular basis, and a short-acting agent is used for breakthrough pain. These are narcotics and require careful supervision. They can be very effective and safe if used properly. People using opioids on a regular basis develop habituation (they must taper slowly or experience withdrawal), but rarely develop addiction (drug-seeking behavior).