Basic Concepts of Dependence, Addiction, Tolerance, and Withdrawal
The antidepressants comprise a wide variety of drugs prescribed most frequently to alleviate anxiety associated with depression or to treat primary depression. Antidepressants are increasingly being used as a primary drug to treat a variety of painful states, often providing considerable relief. The newer antidepressants, which selectively inhibit serotonin uptake, are currently used most frequently for depression, while the tricyclics are often used as analgesic agents-especially for neuropathic pain. Interference of metabolism of phenothiazines and tricyclic antidepressants, when both agents are used concomitantly, has also been reported as has the ability of phenothiazines to 'competitively' diminish binding of tricyclics to plasma proteins, resulting in a greater likelihood of cardiac toxicity. The potential interactions that may occur between antidepressants and a considerable number of other drugs often used in chronic pain states necessitates a careful individual evaluation prior to their use, especially in the elderly or in persons with cardiovascular disease.