Citalopram dosage

A small, flexible dose study of citalopram (dosage range = 10-40 mg/day) in 14 Hispanic and 6 non-Hispanic (non-White) depressed HIV-positive patients conducted in Miami also showed no differences in response rate or effective dose between ethnicities (Currier etal., 2004). In addition, Hispanic patients did not have a significantly higher attrition rate compared to non-Hispanics. 

However, in a 39-year-old man with a schizoaffective disorder, citalopram 40 mg/day appeared to increase plasma clozapine concentrations and increased adverse effects (33). The adverse effects settled within 2 weeks of a reduction in citalopram dosage to 20 mg/day, with a corresponding 25% fall in clozapine concentrations. It is possible that at higher doses, citalopram can increase clozapine concentrations, perhaps through inhibition of CYP1A2 or CYP3A4. 

The authors of the citalopram study say that while cimetidine certainly causes an increase in the serum levels of citalopram, the extent is only moderate and because the drug is well tolerated and there are very considerable pharmacokinetic variations between individual subjects, they consider that there is no need to reduce the citalopram dosage. This advice is most likely applicahle to escitalopram, the S-isomer of citalopram. However, the manufacturer of escitalopram suggests caution, and advises that a reduction in the dose of escitalopram may he necessary (based on monitoring of adverse effects) during concurrent treatment. ... 

The FDA warning on citalopram remains controversial. A retrospective cohort study [34 ], using Veterans Health Administration data collected between 2004 and 2009 from depressed patients who either received a prescription for citalopram (n=6,18,450) or a comparison medication, sertraline (n=3,65,898), found citalopram daily doses of above 40 mg were not associated with a higher risk of ventricular arrhythmia, or cardiac or noncardiac death. In fact, the authors found that citalopram dosages above 40 mg per day were associated with a statistically significantly reduced risk of ventricular arrhythmia, all-cause mortality and noncardiac mortality compared to doses of 20 mg or less. 

Gastpar M et al Comparative efficacy and safety of a once-daily dosage of hypericum extract STW3-VI and citalopram in patients with moderate depression A double-blind, randomized, multicenter, placebo-controlled study. 

A 29-year-old woman took citalopram (40 mg/day) while breast feeding her 5-week-old daughter. The maternal citalopram concentrations were 99 ng/ml in the serum and 205 ng/ml in the breast milk. The serum concentration in the infant was 13 ng/ml, and the child s sleep was fitful and disturbed. The dosage of citalopram was reduced to 20 mg/day and the two feeds after each daily dose were replaced by artificial nutrition. One week later the infant was sleeping normally, and the serum citalopram concentrations in mother and infant had fallen to 35 ng/ml and 2 ng/ml, respectively. 

Both theophyUine and citalopram are metabolized by CYP1A2. In an open, multiple-dose study in 13 healthy nonsmoking volunteers, steady-state citalopram therapy had no significant effect on theophylhne metabolism. The authors suggested that dosage adjustment of theophyUine may not be necessary in patients taking concurrent citalopram (52). The most frequent treatment-related adverse effects were fatigue and nausea. 

Recommended initial doses and dosage ranges are shown in Table 67-3. The usual initial adult dose of most TCAs is 50 mg at bedtime, and the dose may be increased by 25 to 50 mg every third day. The recommended initial dose for the SSRIs is fluoxetine, 10 to 20 mg paroxetine, 20 mg sertraline, 50 mg citalopram, 20 mg and esci-talopram 10 mg. 

The starting dose for fluvoxamine is 50 mg/day, which is then increased as tolerated and needed up to 300 mg/day divided into twice-daily doses. If citalopram is used, the initial dose is 20 mg/day, and it may be increased to 40 mg/day after 2 weeks. The starting dose for escitalopram is 10 mg/day, and it can be increased to a maximum of 20 mg/day. The dosage should be tapered slowly (i.e., decreasing sertraline by 50 mg/month or paroxetine by 10 mg/month) to decrease... 

Clomipramine, fluoxetine, sertraline, paroxetine, fluvoxamine, and citalopram are extensively metabolized in the Liver, and patients with significant liver disease should be prescribed these drugs cautiously and in lower doses than those used in healthy subjects. The pharmacokinetics of fluoxetine and fluvoxamine were similar in patients with renal faUme and in healthy subjects however, the manufacturer recommends starting with a lower dose in patients with renal impairment. The pharmacokinetics of sertraline are not altered in patients with significant renal dysfunction, and dosage adjustment is not necessary in these patients. Increased plasma concentrations of paroxetine occur in subjects with renal impairment. The initial dose of paroxetine should be reduced in patients with severe renal impairment, and upward titration should occm more slowly. No dosage adjustment is necessary for patients with mild to moderate renal impairment receiving citalopram. 

For perimenopausal depression, antidepressants usually are dosed daily at standard dosages for major depression, although some women may respond to lower doses. Estradiol deficiency may decrease the activity of 5-HT and decrease the efficacy of antidepressants. Two open-label studies have reported that citalopram in doses of 20-60 mg/day was effective in treating depression in peri- and postmenopausal women and had augmenting effects in depressed subjects who were still symptomatic after treatment with transdermal estradiol (i.e., improved symptoms of anxiety and somatic complaints). " ... 

The manufacturers say that fluoxetine 60 mg daily for 8 days caused an increase of 16% in olanzapine maximum serum levels and a 16% decrease in clearance. These differences were considered to be too small to necessitate dosage adjustments. Similar results were found in a published study. A case report describes a patient who had been taking fluoxetine 80 mg daily for several weeks with no adverse effects who developed the serotonin syndrome within 3 weeks of starting to take olanzapine 5 mg daily. His symptoms resolved after discontinuing the fluoxetine, and he was later able to tolerate a 20 mg daily dose of fluoxetine and olanzapine with no further adverse effects. The serotonin syndrome has also been reported in a patient taking olanzapine, citalopram and lithium, see Olanzapine + Lithium , p.756. 

Theophylline serum levels can be markedly and rapidly increased by fluvoxamine. Toxicity will develop if the theophylline dosage is not suitably reduced. Some preliminary clinical evidence su ests that fluoxetine and citalopram may not interact, and in vitro evidence su ests that paroxetine and sertraline are also unlikely to interact... 

Another example of chiral switching is that of the selective serotonin reuptake inhibitor (SSRI) antidepressant Celexa, which was introduced to the market in 1998 by Forest Laboratories. Celexa is a racemic mixture of (i )-citalopram oxalate and (5)-citalopram oxalate. While orrly the (S) enantiomer has therapeutic antidepressant properties, both enantiomers contribute to the side effects of the drug and therefore limit effectiveness and patient tolerance. In 2002, the FDA approved Lexapro, a new antidepressant derived from Celexa but from which the therapeutically ineffective (R) enantiomer has been removed. The benefits of isolating the active isomer include smaller required dosages, reduced side effects, and a faster and better patient response to the drag. 

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