Bupropion Tricyclic antidepressants

Nortriptyline. Nortriptyhne, a tricychc antidepressant, has been shown in double-blind, placebo-controlled randomized trials to be superior to placebo for smoking cessation (Prochazka et al. 1998). Nortriptyline appears to have efficacy comparable to that of bupropion for smoking cessation (Hall et al. 2002). The efficacy of this agent may be improved with more intensive behavioral therapies (Hall et al. 1998). Nortriptyline s mechanism of action is thought to relate to its noradrenergic and serotonergic reuptake blockade, because these two neurotransmitters have been implicated in the neurobiology of nicotine dependence. Side effects of nortiptyline are typical of tricyclic antidepressants and include dry mouth, blurred vision, constipation, and orthostatic hypotension. Nortriptyline appears to have some utility for smokers with a past history of major depression, and it can be recommended as a second-... 

Guidelines agree that when antidepressants must be used, they should be combined with a mood-stabilizing drug to reduce the risk of mood switch to hypomania or mania.17,41 The question of which antidepressant drugs are less likely to cause a mood switch is not resolved. Anecdotal reports suggested bupropion may be less likely to cause this effect, but systematic reviews have not supported this conclusion. Prevailing evidence recommends that tricyclic antidepressants be avoided.41,43... 

The proposed mechanism of ADHD pharmacotherapy is to modulate neurotransmitters in order to improve academic and social functioning. Pharmacologic therapy can be divided into two categories stimulants and non-stimulants. Stimulant medications include methylphenidate, dexmethylphenidate, amphetamine salts, and dextroamphetamine, whereas non-stimulant medications include atomoxetine, tricyclic antidepressants (e.g., imipramine), clonidine, guanfacine, and bupropion. 

The tricyclic antidepressants (TCAs), such as imipramine, can alleviate symptoms of ADHD. Like bupropion, TCAs likely will improve symptoms associated with comorbid anxiety and depression. The mechanism of action of TCAs is in blocking norepinephrine transporters, thus increasing norepinephrine concentrations in the synapse the increase in norepinephrine is believed to alleviate the symptoms of ADHD. TCAs have been demonstrated to be an effective non-stimulant option for ADHD but less effective than stimulants. However, their use in ADHD has declined owing to case reports of sudden death and anticholinergic side effects6,13 (Table 39-3). Further, TCAs may lower seizure threshold and increase the risk of car-diotoxicity, (e.g., arrythmias). Patients starting on TCAs should have a baseline and routine electrocardiograms. 

Many neurotransmitters are inactivated by a combination of enzymic and non-enzymic methods. The monoamines - dopamine, noradrenaline and serotonin (5-HT) - are actively transported back from the synaptic cleft into the cytoplasm of the presynaptic neuron. This process utilises specialised proteins called transporters, or carriers. The monoamine binds to the transporter and is then carried across the plasma membrane it is thus transported back into the cellular cytoplasm. A number of psychotropic drugs selectively or non-selectively inhibit this reuptake process. They compete with the monoamines for the available binding sites on the transporter, so slowing the removal of the neurotransmitter from the synaptic cleft. The overall result is prolonged stimulation of the receptor. The tricyclic antidepressant imipramine inhibits the transport of both noradrenaline and 5-HT. While the selective noradrenaline reuptake inhibitor reboxetine and the selective serotonin reuptake inhibitor fluoxetine block the noradrenaline transporter (NAT) and serotonin transporter (SERT), respectively. Cocaine non-selectively blocks both the NAT and dopamine transporter (DAT) whereas the smoking cessation facilitator and antidepressant bupropion is a more selective DAT inhibitor. 

Drug therapies include tricyclic antidepressants and SSRIs. Treatment should be continued for at least 29 weeks. Nortriptyline, amitriptyline, clomipramine, desipramine, fluvoxamine, and bupropion have been used successfully. 

Nortriptyline (Pamelor). A recent study suggested that the tricyclic antidepressant nortriptyline, like bupropion, is effective in the treatment of smoking cessation. Nortriptyline does not have any significant effect on dopamine reuptake activity, but it does increase norepinephrine availability. Like bupropion, nortriptyline may therefore reduce the physical symptoms of nicotine withdrawal. Because nortriptyline carries the danger of lethality in overdose and has the unfavorable side effect profile of the tricyclics, we do not recommend its use for smoking cessation. However, it does raise the question as to whether other newer antidepressants that increase norepinephrine activity (e.g., venlafaxine, mirtazapine, duloxetine) may also prove to be effective treatments for nicotine withdrawal. 

The so-called atypical antidepressants such as venlafaxine and bupropion can be tried, but their safety and efficacy in treating patients with dementia have not been well studied. The older tricyclic antidepressants and monoamine oxidase inhibitors are not tolerated well by demented patients and should be avoided. Two possible exceptions are nortriptyline (Pamelor) and desipramine (Norpramin), but even these should be tried only after the newer antidepressants have proved ineffective. 

Antidepressants. Depression after TBl is routinely treated with antidepressant medicines. Although all antidepressants are potentially helpful, antidepressants prone to burdensome side effects, particularly sedative and anticholinergic side effects, should generally be avoided, as they are likely to be tolerated poorly by these patients. In addition, antidepressants that may increase the risk for seizure, such as many of the older tricyclic antidepressants (TCAs) and bupropion (Well-butrin), should be avoided because post-TBl patients as a rule are already more vulnerable to seizures. 

Nomifensine and bupropion are examples of non-tricyclic antidepressants that facilitate catecholaminergic function. These drugs have the advantage over the TCAs of being non-sedative in therapeutic doses. The... 

There are four classes of antidepressants tricyclic antidepressants (imipramine, trimipramine, amitriptyline, doxepin, desipramine, protriptyline, nortriptyline, amoxapine, maprotiline) monoaminooxidase (MAO) inhibitors (phenelzine, isocarboxazid, tranylcypromine) second-generation antidepressants or atypical antidepressants, which are a chemically dissimilar group of recently proposed drugs (bupropion, trazodone, fluoxetine) and amphetamines and other stimulators of the CNS (dextroamphetamine, methylphenidate). 

Bupropion is an a-aminoketone that is structurally related to amphetamines, and it exhibits unique activity comparable to that of other antidepressants. It is believed that bupropion restores the total amount of norepinephrine in the body. This compound is a poor reuptake inhibitor of dopamine, and does not exhibit anticholinergic activity or inhibit MAO. Its efficacy as an antidepressant is comparable to that of tricyclic antidepressants, and as a serotonin uptake inhibitor it is comparable to fluoxetine. It is preferable to use amoxapine. Synonyms of bupropion are amphebutamon and wellbutrin. 

Drugs that can decrease carbamazepine serum levels include charcoal, cisplatin, doxorubicin, felbamate, hydantoins, rifampin, phenobarbital, primidone, theophylline. The serum levels of oral contraceptives, haloperidol, bupropion, anticoagulants, felbamate, valproic acid, felodipine, tricyclic antidepressants, acetaminophen, ziprasidone, voriconazole, topiramate, tiagabine, olanzapine, and lamotrigine can be lowered by carbamazepine. 

Use caution in patients with a recent history of Ml or unstable heart disease. Bupropion was well tolerated in depressed patients who had previously developed orthostatic hypotension while receiving tricyclic antidepressants and was generally well tolerated in depressed patients with stable CHF. Bupropion was associated P.784... 

Geriatric Considerations - Summary Bupropion has several advantages as an antidepressant agent for use in older adults. It has neither the anticholinergic or cardiac toxicities of the tricyclic antidepressants, and has fewer sexual side effects than selective serotonin reuptake inhibitors. Because this drug may lower seizure threshold, it should be used with caution in older adults with increased risk of seizures (e.g., previous stroke, early-onset Alzheimer s disease). 

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. 

Although the efficacy of tricyclic antidepressants in the treatment of unipolar depression is beyond reproach, the side-effect profile of these agents makes them less desirable as first-line therapeutic agents. Introduction of selective serotonin reuptake inhibitors (SSRIs) such as fluoxetine, paroxetine, sertraline, citalopram and fluvoxamine in the past decade has revolutionized the treatment of depression universally. The side-effect profile of SSRIs, such as nausea, diarrhea and sexual dysfunction, is considerably more benign than that of tricyclic drugs. Multiple controlled trials have proven the efficacy of SSRIs vs. placebo (Nemeroff, 1994). Recently, a number of SNRIs (serotonin and noradrenaline reuptake inhibitors) and so-called atypical antidepressants have been marketed that may have additional advantages over SSRIs, such as more rapid onset of action (venlafaxine. mirtazapine) and low sexual side-effect potential ( bupropion, nefazodone). Additionally, it appears that venlafaxine may be more efficacious in cases of treatment-refractory depression (Clerc et al., 1994 Fatemi et al., 1999). Finally, in a recent report (Thase et al., 2001),... 

Biotransformation The process by which a drug is converted to more polar substances (i.e., metabolites), which are then eliminated from the body either in the urine or in the stool (e.g., demethylated and hydroxylated metabolites of tricyclic antidepressants the three metabolites of bupropion). 

First-pass metabolism (first-pass effect) The passage of the drug from the portal circulation into hepatocytes and conversion there into metabolites. These metabolites may have a pharmacological profile different from that of the parent drug. They are typically then excreted by the hepatocytes into the biliary system and pass back into the small bowel where enterohepatic recirculation may occur (e.g., benzodiazepines, bupropion, nefazodone, neuroleptics, tricyclic antidepressants). 

The depressive phase of manic-depressive disorder often requires concurrent use of an antidepressant drug (see Chapter 30). Tricyclic antidepressant agents have been linked to precipitation of mania, with more rapid cycling of mood swings, although most patients do not show this effect. Selective serotonin reuptake inhibitors are less likely to induce mania but may have limited efficacy. Bupropion has shown some promise but—like tricyclic antidepressants—may induce mania at higher doses. As shown in recent controlled trials, the anticonvulsant lamotrigine is effective for many patients with bipolar depression. For some patients, however, one of the older monoamine oxidase inhibitors may be the antidepressant of choice. Quetiapine and the combination of olanzapine and fluoxetine has been approved for use in bipolar depression. 

D6 Tricyclic antidepressants (TCAs), benztropine, perphenazine, clozapine, haloperidol, codeine/oxycodone, risperidone, class Ic antiarrhythmics, 3 blockers, trazodone, paroxetine, maprotiline, amoxapine, duloxetine, mirtazapine (partly), venlafaxine, bupropion Fluoxetine, paroxetine, duloxetine, hydroxybupropion, methadone, cimetidine, haloperidol, quinidine, ritonavir Phenobarbital, rifampin... 

Newer antidepressants (eg, fluoxetine, paroxetine, citalopram, venlafaxine) are mostly SSRIs and are generally safer than the tricyclic antidepressants and monoamine oxidase inhibitors, although they can cause seizures. Bupropion (not an SSRI) has caused seizures even in therapeutic doses. Some antidepressants have been associated with QT prolongation and torsade de pointes arrhythmia. SSRIs may interact with each other or especially with monoamine oxidase inhibitors to cause the serotonin syndrome, characterized by agitation, muscle hyperactivity, and hyperthermia (see Chapter 16). 

Atypical antidepressants represent a heterogeneous group comprising agents that interfere only weakly or not at all with monoamine reuptake (trazodone, nefazo-done, bupropion, mirtazapine), preferentially block reuptake of norepinephrine (re-boxetine), or act as dual inhibitors of 5-HT and norepinephrine reuptake (venlafaxine, milnacipran, duloxetine). Venlafaxine appears to be as effective as tricyclic antidepressants in severe depression. 

Peck AW, Stern WC, Watkinson C. Incidence of seizures during treatment with tricyclic antidepressant drugs and bupropion. J Clin Psychiatry 1983 44(5 Part 2) 197-201. 

Bupropion has about the same seizure potential as tricyclic antidepressants (SEDA-8, 30), but the manufacturers noted an increased risk of seizures in patients taking over 600 mg/day in combination with lithium or neuroleptic drugs (SEDA-10, 20). 

Medications play an important part in the treatment of ADD. Stimulants are the mainstay of the treatment of ADD methylphenidate (Ritalin), dextroamphetamine (Dexedrine), and pemoline (Cylert). These differ in their half-lives, with Ritalin having the shortest and Cylert the longest. A warning has recently been issued about Cylert because of reports of sometimes fatal liver toxicity. Thus, it is recommended that it be used only if methylphenidate and dextroamphetamine are ineffective. There is individual variability in resporise, so that a person who does not respond to one may respond well to another. Other medications can also be effective in the treatment of ADD and may be useful, especially in residual ADD, where substance abuse may be an issue. These include tricyclic antidepressants (especially desipramine and imi-pramine) SSRIs, bupropion, venlafaxine, and clonidine. There are reports of antipsy-chotics and lithium being helpful in selected cases, as well. 

Clinically important, potentially hazardous interactions with amitriptyline, amoxapine, amphetamines, bupropion, citalopram, clomipramine, cyproheptadine, desipramine, dextroamphetamine, dextromethorphan, diethylpropion, dopamine, doxepin, entacapone, ephedra, ephedrine, epinephrine, fluoxetine, fluvoxamine, ginseng, imipramine, levodopa, mazindol, meperidine, methamphetamine, nefazodone, nortriptyline, paroxetine, phendimetrazine, phentermine, phenylephrine, pizotifen, propoxyphene, protriptyline, pseudoephedrine, rizatriptan, sertraline, sibutramine, sumatriptan, sympathomimetics, tramadol, tricyclic antidepressants, trimipramine, tryptophan, venlafaxine, zolmitriptan... 

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