Antidepressant agents desipramine

Maprotiline (Ludiomil) and amoxapine (Asendin) are heterocyclic antidepressant agents that are not members of the tricyclic family. However, their pharmacology is so similar to that of the tricyclic amines that they are included for discussion purposes with this class of agents. Desipramine and nortriptyline are major metabolites of imipramine and amitriptyline, respectively. 

Tricyclic antidepressants (eg, amitriptyline, desipramine, doxepin, many others see Chapter 30 Antidepressant Agents) are among the most common prescription drugs involved in life-threatening drug overdose. Ingestion of more than 1 g of a tricyclic (or about 15-20 mg/kg) is considered potentially lethal. 

Chronic pain patients tend to have concurrent depression however, the antidepressants chosen may not have any pain-relieving properties. Antidepressants that affect one neurotransmitter in the brain, such as selective serotonin reuptake inhibitors have not appeared to be effective in the management of pain in clinical trials. Antidepressants that affect multiple neurotransmitters— namely, serotonin and norepinephrine—have been shown to be effective pain relievers.Two published metaanalyses have shown that tricyclic antidepressants amitriptyline, desipramine, imipramine, and nortriptyline are the most effective treatment for the management of neuropathic pain. ° These publications review the published clinical trial data for all agents available for the management of neuropathic pain. 

OTHER THERAPEUTIC USES OE THESE DRUGS The various antidepressant agents have found broad utility in other disorders that may not be related psychobiologicaUy to the mood disorders. Current applications include rapid but temporary suppression of enuresis with low (e.g., 25 mg) pre-bedtime doses of tricyclic antidepressants, including imipramine and nortriptyline, by uncertain mechanisms in children and in geriatric patients, as well as a beneficial effect of duloxetine on urinary stress incontinence. Antidepressants have a growing role in attention-deficit/hyperactivity disorder in children and adults, for which imipramine, desipramine, and nortriptyline appear to be effective, even in patients responding poorly to or who are intolerant of the stimulants (e.g., methylphenidate). Newer NE selective reuptake inhibitors also may be useful in this disorder atomoxetine is approved for this application. Utility of SSRIs in this syndrome is not established, and bupropion, despite its similarity to stimulants, appears to have limited efficacy. 

Tricyclic antidepressants (TCAs) such as amitriptyline and doxepin have been used with some success in the treatment of IBS-related pain (Table 18-5). They modulate pain principally through their effect on neurotransmitter reuptake, especially norepinephrine and serotonin. Their helpfulness in functional gastrointestinal disorders seems independent of mood-altering effects normally associated with these agents. Low-dose TCAs (e.g., amitriptyline, desipramine, or doxepin 10 to 25 mg daily) may help patients with IBS who predominantly experience diarrhea or pain. 

Antidepressant medications appear to be useful for certain children and adolescents, particularly those who have severe or psychotic depression, fail psychotherapeutic measures, or experience chronic or recurrent depression. SSRIs generally are considered the initial antidepressants of choice, although comorbid conditions may favor alternative agents. Clinicians should be aware of the possibility of behavioral activation with the SSRIs, including such symptoms as impulsivity, silliness, daring conduct, and agitation.44 Desipramine should be used with caution in this population because of several reports of sudden death, and a baseline and follow-up electrocardiogram (ECG) may be warranted when this medication is used to treat pediatric patients.9... 

Other alternatives to the stimulants that have been studied for treatment of ADHD in children and adults include the tricyclic antidepressants desipramine and nortriptyline the newer antidepressants bupropion, venlafaxine, and atomoxetine the beta-blocker pindolol and the selective monoamine oxidase inhibitor, deprenyl. Across these agents, the number of controlled studies varies from none (nortriptyline) to four (bupropion). Only deprenyl and desipramine have been studied in children with ADHD and tic disorders. 

HCA is the term is used to refer to both TCAs and analogues of these agents, such as maprotiline and amoxapine. TCAs are by far the most commonly used HCAs and include tertiary amines such as amitriptyline, doxepin, and imipramine and secondary amines such as desipramine and nortriptyline. Most secondary amines could also be viewed as NE-selective antidepressants, while the hallmark of tertiary amine TCAs is their effects on multiple neurotransmitters over their clinically relevant dosing range. 

For chronic abdominal pain, low doses of tricyclic antidepressants (eg, amitriptyline or desipramine, 10-50 mg/d) appear to be helpful (see Chapter 30). At these doses, these agents have no effect on mood but may alter central processing of visceral afferent information. The anticholinergic properties of these agents also may have effects on gastrointestinal motility and secretion, reducing stool frequency and liquidity. Finally, tricyclic antidepressants may alter receptors for enteric neurotransmitters such as serotonin, affecting visceral afferent sensation. 

It has been known since the mid-1980s that clomipramine, a potent but nonse-lective serotonin reuptake inhibitor, is effective in reducing OCD symptoms. Since then, numerous studies have confirmed the superiority of clomipramine over placebo in OCD patients, whereas other antidepressant medications with less potent inhibitory effects on serotonin reuptake (e.g., nortripytline, desipramine) seem to be ineffective in OCD. Demonstration of the anti-OCD actions of all five SSRIs, namely, fluoxetine, sertraline, paroxetine, fluvoxamine, and citalopram, also supports the hypothesis that the antiobsessional effects of these various pharmacologic agents is due to their potent serotonergic reuptake blocking activity. 

CNS and cardiovascular actions of d,l-methylphenidate could theoretically be enhanced by combination with agents that block norepinephrine reuptake, such as the tricyclic antidepressants desipramine or protriptyline, venlafaxine, duloxetine, atomoxetine, milnacipran, and reboxetine... 

Cocaine inhibits the transporters for norepinephrine, serotonin, and dopamine. Binding of cocaine to the dopamine transporter Inhibits reuptake of dopamine, thus prolonging signaling at key brain synapses indeed, the dopamine transporter Is the principal brain cocaine receptor. Therapeutic agents such as the antidepressant drugs fluoxetine (Prozac) and imipramlne block serotonin uptake, and the tricyclic antidepressant desipramine blocks norepinephrine uptake. I... 

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