Direct cost saving of SSRI overdose

Antidepressants, old and new. A review of their adverse effects and toxicity in overdose

The newer antidepressants are as efficacious as the older agents in the treatment of depression. They have a side effect profile that is different from the older drugs and are generally better tolerated. Drug-drug interactions do exist with some of these agents and can usually be predicted from knowledge of their metabolism. When taken in overdose as the sole agents they are rarely fatal; seizures, nausea, vomiting, decreased level of consciousness, and tachycardia are common. In combination with other drugs, toxicity can be more severe. The serotonin syndrome can occur with many of these drugs, and the emergency physician must be vigilant in the evaluation of the overdose patient. CAs and older MAOIs are still in use and remain dangerous when taken in overdose. Patients asymptomatic after a period of observation in the ED usually can be discharged after psychiatric evaluation, when it is required.

Systematic review and guide to selection of selective serotonin reuptake inhibitors

A meta-analysis of 20 short term comparative studies of 5 selective serotonin reuptake inhibitors (SSRIs; citalopram, fluoxetine, fluvoxamine, paroxetine and sertraline) has shown no difference in efficacy between individual compounds but a slower onset of action of fluoxetine. There were suggestions that fluoxetine caused more agitation, weight loss and dermatological reactions than the other SSRIs. More patients discontinued fluvoxamine and fewer patients stopped sertraline because of adverse effects than their comparator SSRIs. The most common adverse reactions to the SSRIs were gastrointestinal (especially nausea) and neuropsychiatric (particularly headache and tremor). Data from the Committee on Safety of Medicines showed more reports of suspected reactions (including discontinuation reactions) to paroxetine, and of gastrointestinal reactions to fluvoxamine and paroxetine, than the other SSRIs during their first 2 years of marketing. Prescription-event monitoring revealed a higher incidence of adverse events related to fluvoxamine than its comparators. There were higher incidences of gastrointestinal symptoms, malaise, sedation and tremor during treatment with fluvoxamine and of sedation, tremor, sweating, sexual dysfunction and discontinuation reactions with paroxetine. Fluoxetine was not associated with a higher incidence of suicidal, aggressive and related events than the other SSRIs. Patients have survived large overdoses of each of the compounds, but concern has been expressed over 6 fatalities following overdoses of citalopram. Drug interactions mediated by cytochrome P450 enzymes are theoretically less likely to occur during treatment with citalopram and sertraline, but there is a sparsity of clinical data to support this. Methodological difficulties and price changes do not allow choice for recommendations on the choice of SSRI based on pharmacoeconomic data. Taking into account the strengths and weaknesses of the methods used to compare drugs, guidelines to the selection of individual SSRIs in clinical practice are proposed. Citalopram should be avoided in patients likely to take overdoses. Fluoxetine may not be the drug of first choice for patients in whom a rapid antidepressant effect is important or for those who are agitated, but it may have advantages over other SSRIs in patients who are poorly compliant with treatment and those who have previously had troublesome discontinuation symptoms. Fluvoxamine, and possibly paroxetine, should not be used as first choice in patients especially prone to SSRI-related adverse reactions, while paroxetine should be avoided if previous discontinuation of treatment was troublesome. When in doubt about the risks of drug interactions, citalopram or sertraline should be considered given the lower theoretical risk of interactions.

Liability in prescribing choice: the example of the antidepressants

OBJECTIVE

The aim of this study is to review issues of legal liability in prescribing choice. Prescribing not only occurs in a medical setting, but also in a social and legal context in this era of evidence-based medicine and greater consumer awareness. Prescribers may be unaware of the legal consequences of medical decision-making and prescribing choice. This issue affects all areas of medicine and can be illustrated by antidepressant choice for major depression.

METHOD

A review was undertaken of liability issues that may arise in the context of prescribing, with particular reference to prescribing antidepressants.

RESULTS

There are legal precedents which illustrate prescribers' potential liability. These impose duties on the prescriber including those of care, to inform, and to respond to patients' wishes. In particular, the duty of care requires that if medicines are of equal efficacy, one should prescribe the best tolerated and least toxic medicine that is most likely to be taken at an effective dose for an adequate duration. While older and newer antidepressants are generally of equal efficacy, the newer agents have higher tolerability, lower toxicity and are less likely to be associated with treatment failure (due to sub-therapeutic dose regimens, or the patient discontinuing medication), disabling psychomotor impairment, dietary interaction or fatal overdose.

CONCLUSIONS

There needs to be compelling reasons for prescribing medicines with a greater likelihood of adverse outcomes such as the older antidepressants (e.g. tricyclics) rather than the newer antidepressants such as RIMAs, SSRIs, SNRIs and 5HT2 receptor antagonists. The higher likelihood of an adverse outcome of treatment where an older antidepressant has been prescribed raises the potential for professional negligence claims to be brought against medical practitioners who prescribe such medicines for reasons other than established medical need.