Pharmacological Management of Pain

Nonopioid analgesics can be subdivided into aspirin-like drugs - nonsteriodal anti-inflammatory drugs, NSAIDS- and acetaminophen. NSAIDs have analgesic, antipyretic, anti-inflammatory, and antithrombotic actions.

Inhibition of prostaglandin synthesis appears to explain their analgesic, antithrombotic, and antipyretic, anti-inflammatory, and antithromobotic actions. Inhibition of prostaglandin synthesis appears to explain their analgesic, antithromobotic, and antipyretic actions, while interference with neutrophil function might account for their anti-inflammatory properties.

These medications are well absorbed, but demonstrate an analgesic ceiling. Gastropathy is the most common side effect and may be neutrophil or prostaglandin - mediated. Renal complications include the nephritic syndrome and interstitial nephritis, which are reversible.

Irreversible papillary necrosis can occur, but is exceedingly rare. NSAIDs should be used cautiously or avoided in patients with a history of peptic ulcer disease or with decreased renal function.

Acetaminophen's analgesic properties are equipotent with aspirin. While it is antipyretic, it is not anti-inflammatory and does not affect platelet function.

Doses exceeding 4 to 6 g/day can be hepatotoxic, and caution should be taken when using combination medications that contain this amount of acetaminophen.

Opioid analgesics are generally not indicated for the treatment of nonmalignant chronic pain. While efficacy without dependence has been reported for Opioid treatment of somatic pain, Opioid use for sympathetic pain and other chronic naturopathic pain disorders has been shown to have poor efficacy.

For Chronic somatic pain, Opioids have improved efficacy, but dependence and tolerance remain a problem in some patients. Chronic malignant pain of somatic origin can be treated effectively with long-term Opioid management.

It should be noted that caffeine could increase the analgesic effects of aspirin-like drugs in the treatment of headaches and other pain syndromes.

Several adjuvant medications have independent analgesic effects or enhance the effects of Opioids. Tricyclic antidepressants have been shown in controlled trials to have analgesic effects independent of their antidepressant properties.

They have also been shown in laboratory animals to enhance the effects of Opioid analgesics with an efficacy 70 times that of aspirin. These effects were not reversed with naloxone. They were reversed by central serotonin depletion, implicating serotonin reuptake blockade as an analgesic mechanism.

Amitriptyline is the best studied of the tricyclics, but its anticholinergic side effects - dry mount, sedation, blurred vision, urinary retention, constipation, or delirium - can make this drug undesirable.

Benzodiazepines are useful in relieving anxiety, but they have no intrinsic analgesic properties. Long-term use can lead to dependence and withdrawal effect, including seizures, muscle cramps, and dysphoria.

If given in combination with Opioids, they can potentiate respiratory depression, even in small doses.