Nefazodone Fluoxetine

CypP450 3A3 /4 Antidepressants tricyclics, nefazodone, fluoxetine, fluvoxamine, citalopram, mirtazepine, venlafaxine Antipsychotics chlorpromazine, clozapine, pimozide, quetiapine, risperidone... 

E. Nefazodone,fluoxetine,mirtazapine, and venlafaxine have minimal effects on seizure threshold. Bupropion in its original formulation caused seizures in 4 in 1000 patients. Although this has been reduced with the slow release form of the medication (Wellbutrin SR), it remains a contraindication to prescribe this medication to patients with a history of seizures. 

High fluvoxamine fluvoxamine fluoxetine paroxetine fluoxetine fluvoxamine nefazodone fluoxetine... 

CYP450 3A inhibitors such as nefazodone, fluoxetine, and fluvoxamine may decrease clearance of triazolam and raise triazolam levels significantly... 

Antidepressants Desipramine, imipramine, sertraline, fluoxetine, paroxetine, venlafaxine, bupropion, nefazodone, mirtazapine, gepirone, amineptine Mixed findings suggest that better designed studies may find a niche for some of these drugs. Amineptine was effective for withdrawal symptoms. 

Certain medications (e.g., cimetidine, diltiazem, erythromycin, fluoxetine, fluvoxamine, isoniazid, itraconazole, ketoconazole, nefazodone, propoxyphene, and verapamil) added to carbamazepine therapy may cause carbamazepine toxicity. 

Drugs that can increase carbamazepine serum levels include cimetidine, danazol, diltiazem, erythromycin, felbamate, clarithromycin, fluoxetine, isoniazid, niacinamide, propoxyphene, ketaconazole, itraconazole, verapamil, valproate, troleandomycin, loratadine, nicotinamide, tricyclic antidepressants, SSRIs, nefazodone, protease inhibitors. 

Drugs that may affect cyclosporine include allopurinol, amiodarone, androgens (eg, danazol, methyltestosterone), anticonvulsants (eg, carbamazepine, phenobarbital, phenytoin), azole antifungals (eg, fluconazole, ketoconazole), beta-blockers, bosentan, bromocriptine, calcium channel blockers, colchicine, oral contraceptives, corticosteroids, fluoroquinolones (eg, ciprofloxacin), foscarnet, HMG-CoA reductase inhibitors, imipenem-cilastatin, macrolide antibiotics, methotrexate, metoclopramide, nafcillin, nefazodone, orlistat, potassium-sparing diuretics, probucol, rifamycins (rifampin, rifabutin), serotonin reuptake inhibitors (SSRIs eg, fluoxetine, sertraline),... 

Rush, A.J., Armitage, R., Gillin, J.C., Yonkers, K.A., Winokur, A., Moldofsky, H., Vogel, G.W., Kaplita, S.B., Fleming, J.B., Mont-plaisir, J., Erman, M.K., Albala, B.J., and McQuade, R.D. (1998) Comparative effects of nefazodone and fluoxetine on sleep in outpatients with major depressive disorder. Biol Psychiatry 44 3-14. 

The initial reports from open studies (Artigas et al. 1994 Blier and Bergeron 1995) suggest that the combination is associated with improved efficacy with probable faster onset of action. This rapid response was reported with augmentation of fluoxetine and paroxetine, and more recently with nefazodone (Bakish et al. 1997), but interestingly not with sertraline or low doses of fluvoxamine. These results needed to be confirmed in placebo-controlled studies, and the reports from large studies do indeed find an acceleration of response measured as time to response and possible superiority of action with some antidepressants at the end of treatment (Perez et al. 1997 Tome de la Granja et al. 1997). 

Area of assessment Clinically sedative antidepressants, e.g. amitriptyline, mianserin, trimipramine Less sedative antidepressants, e.g. bupropion, fluoxetin, moclobemide, nefazodone ... 

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),... 

Treatment of GAD can be undertaken using a number of pharmacological agents. Benzodiazepines have been found to be superior to placebo in several studies and all benzodiazepines appear to be equally effective. However, side effects include sedation, psvchomotor impairment, amnesia and tolerance (Chapter 1). Recent clinical data indicate that SSRIs and SNRIs are effective in the treatment of acute GAD symptoms. Venlafaxine, paroxetine and imipramine have been shown to be effective antianxiety medications in placebo-controlled studies. Case studies also indicate the usefulness of clomipramine, nefazodone, mirtazapine, fluoxetine and fluvoxamine in GAD. Buspirone, a 5-HTla receptor partial agonist, has been shown to be effective in several placebo-controlled, double-blind trials (Roy-Byme and Cowley, 2002). Buspirone has a later onset of action than both benzodiazepines and SSRIs but with the advantage of being non-addictive and non-sedating. 

In contrast to anticonvulsants and alcohol, drugs such as bupropion, fluoxetine, fluvoxamine, nefazodone, quinidine, paroxetine, and some antipsychotics can inhibit specific CYP enzymes (7, 11, 36, 37, 41, 42, 43 and 44). Thus, TCAs, certain BZDs, bupropion, some steroids, and antipsychotics can all have their metabolism inhibited by drugs such as fluoxetine. For example, fluoxetine at 20 mg/day produces on average a 500% increase in the levels of coprescribed drugs which are principally dependent on CYP 2D6 for their clearance. That can lead to serious or even life-threatening toxicity if the drug has a narrow therapeutic index and the dose is not adjusted for the change in clearance caused by the coadministration of fluoxetine. 

Two open label studies have been done with nefazodone (. 367, 368). As discussed earlier, the value of such open label studies is dubious. Moreover, this strategy is limited by the divided dose schedule recommended for the immediate release formulation of nefazodone, the need for dose adjustment, and the potential for complicated drug-drug interactions, particularly when switching from fluoxetine to nefazodone. 

TABLE 7-25. Comparison of the placebo-adjusted incidence rate (%) of frequent adverse effects for fluoxetine, sertraline, paroxetine, venlafaxine, and nefazodone... 

There is a great disparity of current knowledge regarding the effects of antidepressants on GYP enzymes. There have been almost no studies to test the potential effects of TCAs, MAOIs, and trazodone on GYP enzymes. There has only been one study with bupropion but it demonstrated that bupropion produces substantial inhibition of GYP 2D6 comparable with the effect of fluoxetine and paroxetine. In contrast to studies in these antidepressants, there have been extensive in vitro and in vivo studies of SSRIs, nefazodone, and venlafaxine. 

Salazar D, Chaikin P, Swanson B, et al. The effects of nefazodone and fluoxetine on platelet serotonin uptake and whole blood serotonin. Clin Pharmacol Ther 1994 55 137. 

The majority of positive studies have found that later generation antidepressants, especially those with strong serotonergic effects, are effective and may have a more rapid onset of action when used for PMDD (27). Thus, studies with SSRIs (e.g., fluoxetine, sertraline), nefazodone, venlafaxine, and clomipramine have all shown promise. In several studies, luteal phase dosing has been as effective or more effective than continuous dosing in women with PMDD. 

BZD hypnotics such as midazolam and triazolam are primarily metabolized via the P450 3A3/4 microenzyme system. Other BZDs often used as hypnotics, such as diazepam, can also be metabolized by CYP 33/4 and CYP 2C19. Any drugs that act as inhibitors or inducers of these isoenzymes could increase or decrease BZD levels, respectively (350). Thus, ketoconazole, macrolide antibiotics (e.g., erythromycin), SSRIs (e.g., fluoxetine-norfluoxetine and fluvoxamine), and other antidepressants (especially nefazodone) may decrease clearance and increase BZD levels to potentially toxic ranges. Conversely, rifampacin, CBZ, and dexamethasone may increase clearance and decrease BZD levels to potentially subtherapeutic ranges. 

A4 Citalopram, escitalopram, TCAs, glucocorticoids, androgens/estrogens, carbamazepine, erythromycin, Ca2+ Fluvoxamine, nefazodone, sertraline, fluoxetine. Barbiturates, glucocorticoids. 

Drugs that may inhibit cytochrome P450 metabolism of other drugs include amiodarone, androgens, atazanavir, chloramphenicol, cimetidine, ciprofloxacin, clarithromycin, cyclosporine, delavirdine, diltiazem, diphenhydramine, disulfiram, enoxacin, erythromycin, fluconazole, fluoxetine, fluvoxamine, furanocoumarins (substances in grapefruit juice), indinavir, isoniazid, itraconazole, ketoconazole, metronidazole, mexile-tine, miconazole, nefazodone, omeprazole, paroxetine, propoxyphene, quinidine, ritonavir, sulfamethizole, verapamil, voriconazole, zafirlukast, and zileuton. 

Lam, Y.W., Alfaro, C.L., Ereshefsky, L., and Miller, M., Pharmacokinetic and pharmacodynamic interactions of oral midazolam with ketoconazole, fluoxetine, fluvoxamine, and nefazodone, J. Clin. Pharmacol, 43(11), 1274-1282, 2003. 

A third important CYP450 enzyme for antidepressants and mood stabilizers is 3A4. Some benzodiazepines (e.g., alprazolam and triazolam) are substrates for 3A4 (Fig. 6—17). Some antidepressants are 3A4 inhibitors, including the SSRIs fluoxetine and fluvoxamine and the antidepressant nefazodone (Fig. 6—18). Administration of a 3A4 substrate with a 3A4 inhibitor will raise the level of the substrate. For example, fluoxetine, fluvoxamine, or nefazodone will raise the levels of alprazolam or triazolam, requiring dose reduction of the benzodiazepine (Fig. 6—18). 

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