Alterations of drug toxicity in neuropsychiatric disease states

Potentially adverse alterations in drug response in patients with neuropsychiatric disease can be divided into two categories: those arising from the pathological state itself (e.g., enhanced responsiveness to phenylephrine in patients with chronic autonomic failure) and those arising from interactions with the pharmacological treatment used for such disease (e.g., reversal of the antihypertensive action of guanethidine by imipramine). Sound knowledge of the pharmacological profile of individual compounds and of the pathophysiology of the disease is essential if drug therapy is to be used safely and effectively in these patients.