Drug treatments for pain is referred to by doctors and pharmacists as the analgesic ladder. Most painkillers fall into three groups: acetylsalicyclic acid or ASA (aspirin); codeine; or morphine. Chronic pain patients are progressed up the ladder by their physicians when the pain worsen or when they can find no other relief (Wells & Nown 1998).
Most of the medications for pain fall into one of the three rungs of the analgesic ladder. Over-the-counter drugs are usually rung one, or aspirinlike; codeine and morphine, rungs two and three, are controlled substances (i.e. needs a doctors prescription) because they are addictive and, thus, can be abuse. In general, morphine-like drugs are not used to treat chronic pain; it may be utilize in particular situations only. Of the three class of drugs previously mention, nonsteroidal anti-inflammatory drugs (NSAIDs) will be discuss first. These drugs are the ASA-like group, which includes aspirin and ibuprofen.
When a person is injured, damaged tissues release a hormone called prostaglandins (PG) which irritate nerve endings and help nerve fibers carry pain messages to the brain (Wells & Nown 1998; Ebadi et al. 1998). In general, ASA-like drugs inhibit the production of (PG), thus, reduce inflammation and pain (Wells & Nown 1998).
On the second rung of the analgesic ladder are the codeine-like drugs, and on the third rung are the morphine-like drugs. Both Codeine- and morphine-like drugs are habit forming. As a result, morphine is not used to treat chronic illness but is an effective drug treatment for acute pain (e.g. postoperative pain or heart attacks; in some cases it is used in cancer pain). When morphine is used for chronic pain, problems are minimized by taking the drug regularly, rather than only in response to pain (Wells & Nown 1998). Morphine is also very addictive, hence abuse of the drug can result for non-pain reasons such as mood disorders and social problems. When given for more than six months, codeine-like drugs, such as oxyxodone and propoxyphene, can also result in the same addiction problem as morphine-like drugs. Finally, secondary analgesics are medication that generally have another prime purpose, but doctors have found that one of their spin-off effects is to reduce certain types of pain (Wells & Nown). The most important ones that affect the central nervous system in some way as to modify pain are tranquilizers, anticonvulsants, and antidepressants
Tranquilizers, which include benzodiazepine, diazepam, and lorazepam are intended to work as a muscle relaxant. These drugs are also addicting and addiction usually form after only six weeks of usage (Wells & Nown 1998). By this time patient should be taken off the medication or it will take over the function of the muscles. Once a person is dependent on these drugs, they are locked in a cycle of chronic pain because they are unable to control their muscles without the pills. In addition, when taken it long-term, the person becomes physically and mentally dependent for the temporary sense of relief and euphoria (Wells & Nown 1998). Thus, tranquilizers should only be use as short-term drugs.
Anticonvulsants on the other hand, are usually drugs used for the treatment of patients suffering from epilepsy. Chronic pain and epilepsy are not normally associated but the ability of these drugs to stabilizes nerve membranes may be the reason why they benefit some people. They work on epilepsy by stopping the hyper-irritability that produces messages going down to the muscles to make them twitch. In chronic pain, anticonvulsants work by reducing excessive electrical activity within the brain or within the spinal cord. Anticonvulsants has been shown to be most effective in providing pain relief for shooting pain or knifelike stabbing pain (Wells & Nown, 1998). These are pains that involve nerve irritation or nerve damage.
In contrast, antidepressants on the other hand are non-addictive secondary analgesics (Wells & Nown, 1998). Hence, they can be used as long-term treatments, especially for peripheral nerve damage. Antidepressants are thought to exert their effect by interfering with serotonin and noradrenaline (Wells & Nown, 1998). Although, their prime function is in treating depression, antidepressant can also be used to reduce pain. In the case of treating chronic pain, some antidepressants have a sedative effect and may be taken over night; they may help chronic-pain sufferers to sleep better. Getting a good night sleep is thought to help people cope with their pains better (Wells & Nown, 1998).