Like the other SSRIs, citalopram is very well tolerated in general. It has a side effect profile markedly different from the older TCAs in that it is generally lacking significant anticholinergic effects. The most commonly reported adverse events (in comparison with placebo) include nausea (8% versus placebo), dry mouth (7.4%), somnolence (7.6%), increased sweating (3.9%), tremor (3%), diarrhea (3.2%), and ejaculation failure (3.3%), based on Lundbeck’s accumulated database of more than 1,000 subjects (Forest Pharmaceuticals Inc. 1998). When compared with the TCAs, only nausea and ejaculation failure are more common with citalopram. Citalopram, therefore, appears to be similar to fluoxetine and sertraline and perhaps superior to fluvoxamine in terms of its side effect profile (). A recent article comparing tolerability of antidepressants based on the Physicians’ Desk Reference along with other published sources suggests that citalopram may in fact have the most favorable side effect profile of the available SSRIs (). Most adverse events have been shown to diminish in frequency during the first few weeks of therapy (). Sexual dysfunction is typically underestimated because patients may fail to spontaneously report these symptoms. In a recent clinical trial of 475 patients with panic disorder, 10% of individuals receiving 40 mg/ day or more of citalopram reported anorgasmia (). Three cases of transient clitoral priapism have been reported during the second week of treatment with citalopram (). However, there have also been reports of lack of sexual impairment in patients who experienced difficulty with other SSRIs ().
Citalopram does not seem to be associated with cardiovascular toxic-ity in the normal dose range. A small and clinically insignificant bradycardia of 5-9 beats per minute has been shown to occur early in treatment (). There is no evidence of citalopram-related QT or other interval changes, suggesting a lack of effect on cardiac conduction and repolarization (). Hematologic, hepatic, and renal functions are essentially unchanged. Moreover, no pattern of unexplained sudden deaths has been reported so far, after use in more than 600,000 patients in Europe (). Similarly, citalopram is not normally associated with any increased risk of seizures. Although discontinuation reactions have been increasingly observed after sudden discontinuation of some of the SSRIs, two studies in which 116 patients were abruptly switched from citalopram to placebo did not apparently result in this difficulty ().
Based on the small number of documented cases in which patients have overdosed on citalopram alone, it appears to be very safe. Of the almost 70 reported overdoses, only 4 involving citalopram alone were lethal, despite consumed amounts estimated up to 5,200 mg (). According to a recent review, only five fatal overdoses involving citalopram in combination with other drugs, such as moclobemide and barbiturates, have been reported (). Generalized seizures and widened QRS complexes have been observed in some overdoses (). Thus, overdoses should be managed with prompt gastric lavage, administration of activated charcoal, and symptomatic management of residual overdose effects, which should probably entail medical observation including electrocardiographic monitoring for at least 24 hours.
In individuals with renal insufficiency, the half-life of citalopram may be somewhat raised. However, this does not ordinarily translate into a need for dose adjustment (). Little is known about the impact of severe renal impairment. Hepatic impairment reduces drug clearance, potentially resulting in a doubling of steady-state concentrations. In individuals with poor liver functioning, therefore, the dose should be kept at the lower end of the range (i.e., 20 mg/day).
Selections from the book: “Current treatments of obsessive-compulsive disorder” (2001).