Fluoxetine dosage

The effects of buspirone are decreased when the drug is administered with fluoxetine Increased serum levels of buspirone occur if the drug is taken with erythromycin or itraconazole Should any of these combinations be required, the dosage of buspirone is decreased to 2.5 mg BID, and the patient is monitored closely. Venlafaxine blood levels increase with a risk of toxicity when administered witii MAOIs or cimetidine There is an increased risk of toxicity when trazodone is administered with the phenothiazines and decreased effectiveness of trazodone when it is administered with carbamazepine Increased serum digoxin levels have occurred when digoxin is administered with trazodone There is a risk for increased phenytoin levels when phenytoin is administered witii trazodone... 

Switching patients to a TCA - Dosage of TCA may need to be reduced, and plasma TCA concentrations may need to be monitored temporarily when fluoxetine is coadministered or has been recently discontinued. 

Administer once daily in the evening, generally beginning with the 6 mg/25 mg capsule. While food has no appreciable effect on the absorption of olanzapine and fluoxetine given individually, the effect of food on the absorption of olanzapine/fluoxetine has not been studied. Dosage adjustments, if indicated, can be made according to efficacy and tolerability. Antidepressant efficacy was demonstrated with olanzapine/fluoxetine in a dose range of olanzapine 6 to 12 mg and fluoxetine 25 to 50 mg. The safety of doses above 18 mg/75 mg has not been... 

In general, the SSRIs have a more tolerable side effect profile than the tricyclic antidepressants with their anticholinergic effects. Review of the rate that subjects in the controlled studies discontinued a SSRI because of adverse effects provides some perspective on how well tolerated the medications are, although the specifics may vary according to dosage and design (e.g., forced titration) and are not directly comparable. The rate of discontinuation was reported to be 12% (4/48) for fluoxetine (Emslie et ah, 1997), 9.7% for paroxetine (Keller et ah, 2001), 13% (12/92) for sertraline (March et ah, 1998), and 33% (19/57) (Riddle et ah, 2001) and 7.9% (5/63) for fluvoxamine (Walkup et ah, 2001). 

For most child psychiatrists, the drug interactions most frequently encountered are interactions with other psychotropics. Fluoxetine inhibits the CYP3A isozymes and thus increase the plasma concentration of the tria-zolobenzodiazepines (alprazolam, midazolam, and triazolam), causing increased psychomotor effects (Shader and Greenblatt, 1995). To avoid unwanted psychomotor effects, the dosage of alprazolam should be decreased when it is coadministered with fluoxetine (Chouinard et ah, 1999). Nefazadone has also been shown to increase the pharmacodynamic effects of triazolam and, to a lesser extent, alprazolam (Chouinard et ah, 1999). 

Like fluoxetine, erythromycin and other macrolides inhibit the CYP-3A isoenzyme and increase the levels and effects of the triazolobenzodiazepines (Shader and Greenblatt, 1995 Chouinard et ah, 1999). Midazolam should be avoided or the dosage dropped by 50% in patients receiving erythromycin (Olkkola et ah, 1993). Ketoconazole and itraconazole may also interact with triazolam and midazolam, and combinations of these drugs should be avoided (Varhe et ah, 1994 Chouinard et ah, 1999). 

Aripiprazole is hepatically metabolized, mainly by two cytochrome P450 enzymes CYP 2D6 and CYP 3A4. Therefore, dosage adjustments are necessary when this medication is given with other medications that either inhibit or induce these enzymes. For example, the dose of aripiprazole should be halved when this medication is given with ketoconazole, a CYP 3A4 inhibitor, or at least decreased when given with fluoxetine, a CYP 2D6 inhibitor. When aripiprazole is given with CYP 3A4 inducers such as carbamazepine, the dose should be doubled. 

In a recent review, Shan and Zaworotko have discussed cocrystals having pharmaceutical interest, and presented several case studies that they used to demonstrate how one could enhance the solubility, bioavailability, and/or stability of drug substances [23]. The systems considered were the cocrystals of fluoxetine hydrochloride with carboxylic acids, itraconazole with dicarboxylic acids, sidenafil with acetylsalicylic acid, and melamine with cyanuric acid. One main conclusion advanced by the authors was that the use of cocrystal systems in pharmaceutical dosage forms was inevitable, and that the main questions were who would benefit and how drastic the influence on development would ultimately turn out to be. 

Wirshing et al. (1992) reported on five cases of a fluoxetine-induced syndrome consisting of akathisia and suicidality. In all five cases, the akathisia and the suicidality remitted when the drug was stopped or reduced in dosage. In one case, a rechallenge with an increased dose of fluoxetine again produced the syndrome. They concluded, Our cases appear to confirm that certain subjects experience akathisia while taking fluoxetine and... 

Catastrophic deterioration, with the severity of obsessive-compulsive symptoms returning to pretreatment levels, was observed in a 21-year-old man when risperidone was added to fluoxetine in a dosage that was stepped up to 3 mg/day (53). 

CYP450 2D6 inhibitors (e.g., paroxetine, fluoxetine, duloxetine) can raise clozapine levels, but dosage adjustment usually not necessary... 

Inhibitors of CYP450 2D6, such as paroxetine, fluoxetine, and quinidine, may increase plasma levels of duloxetine and require a dosage reduction of duloxetine... 

Theoretically, concomitant use with CYP450 2D6 Inhibitors (such as paroxetine and fluoxetine) could raise zuclopenthixol plasma levels and require dosage reduction... 

Fluoxetine Potentiation (174) Unknown Adjust dosage or avoid concurrent use... 

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