Review of Quetiapine Side Effects

Quetiapine Side Effects Review of Quetiapine Side Effects David L. Garver, M.D. The newest atypical antipsychotic medication to be approved by the U.S. Food and Drug Adminis- tration, quetiapine is a drug that awaits a wide range of clinical and head-to-head comparisons. Never- © Copyrighttheless, clinical trials 2000currently available Physicians suggest that quetiapine Postgraduate has a beneficial side Press, effect profile, Inc. particularly with regard to extrapyramidal symptoms. To date, quetiapine has also proved effective in the treatment of schizophrenia, but its efficacy, while clearly superior to that of placebo, seems no greater than that of haloperidol or chlorpromazine. Clinical trials have supported the use of quetiapine in treating elderly patients. Further research is necessary to establish the clinical profile of quetiapine. (J Clin Psychiatry 2000;61[suppl 8]:31–33) uetiapine is the newest atypical antipsychotic to be were no significant statistical differences between any Q approved by the U.S. Food and Drug Administra- dose of quetiapine and haloperidol. Peuskens and Link3 tion. As a result, there is less information available to date found no statistical differences between quetiapine (mean about quetiapine than there is about theOne other personal atypical anti-copy maydaily be dose printed = 407 mg) and chlorpromazine (mean daily psychotics. Nonetheless, the limited number of clinical dose = 384 mg) in a 6-week double-blind study in 201 trials to date confirms preclinical assessments of quetia- hospitalized patients. The efficacy of the 2 treatments was pine as an atypical antipsychotic1 and suggests that quetia- similar for both positive and negative symptoms. pine, although not clearly superior to haloperidol2 or A meta-analysis4 of the randomized controlled trials of chlorpromazine3 in efficacy, has a benign side effect pro- quetiapine, olanzapine, risperidone, and sertindole (not file—particularly with regard to extrapyramidal symp- marketed in the United States) also revealed that while ris- toms (EPS). This side effect profile makes the drug par- peridone and olanzapine are slightly more effective than ticularly attractive in treating the elderly. haloperidol in the treatment of global symptomatology and negative symptoms of schizophrenia, quetiapine is EFFICACY OF QUETIAPINE equal to haloperidol for the treatment of overall symptomatology and slightly less effective than haloperidol in the In clinical trials, the efficacy of quetiapine was superior treatment of negative symptoms. to that of placebo and similar to that of conventional antipsychotics.2,3 Arvanitis et al.2 evaluated 5 fixed doses of QUETIAPINE EFFECTS quetiapine (75–750 mg/day) in 361 patients diagnosed AT THE RECEPTOR SITES with an acute exacerbation of schizophrenia to compare efficacy of quetiapine versus placebo and haloperidol as An examination of the receptor site activity induced by measured by the Brief Psychiatric Rating Scale. At week quetiapine will shed light on the side effect profile of the 6, the differences from baseline were statistically signifi- drug. One or more receptors can have actions that cause cant (p ≤ .05) versus placebo for the 4 highest doses of similar side effects, but the side effects of quetiapine re- quetiapine (150, 300, 600, and 750 mg/day), while there main mild nonetheless. Histaminic Quetiapine blockade of the histaminic (H1) receptor (IC50 = 30 nM) is very high. This blockade causes sedation From the VA North Texas Medical Center, Dallas, Texas. Dr. in 18% and dizziness in 10% of patients.5 The sedation is Garver is now with the Department of Psychiatry and Behavioral Sciences, University of Louisville, Louisville, Ky. an effect not only of the H1 blockade but also of α Presented at the planning roundtable “Side Effects of 1-adrenergic blockade. Quetiapine produces substantially Antipsychotic Medications: Physician’s Choice of Medication fewer EPS than placebo. In a fixed-dose trial of quetia- and Patient Compliance,” held January 22, 1999, in Dallas, 2 Texas, and sponsored by an unrestricted educational grant pine, patients’ improvements on the Simpson-Angus from Janssen Pharmaceutica, L.P. Neurologic Rating Scale increased as the dosage of quetia- Reprint requests to: David L. Garver, M.D., Department of 6 Psychiatry and Behavioral Sciences, University of Louisville pine increased (Figure 1). Goldstein and Arvanitis have School of Medicine, Louisville, KY 40292. indicated that blockade of H1 receptors inhibits response J Clin Psychiatry 2000;61 (suppl 8) 31 David L. Garver 8 Figure 1. A Fixed-Dose Trial of Quetiapine, Haloperidol, and McManus et al., reporting after 12 weeks of an ongoing Placebo: Simpson-Angus Neurologic Rating Scale Total open-label study of quetiapine in 151 elderly patients with Scoresa DSM-IV diagnoses of psychotic disorders, found that adverse events due to EPS occurred in 6% of the study popu- Worsened 2 lation. Doses ranged from 25 to 800 mg/day. In the Placebo 2 Quetiapine Arvanitis et al. clinical trial, the incidence of EPS was no Haloperidol 1 more common in patients taking any dose of quetiapine than it was in patients taking a placebo. While no patients treated with quetiapine withdrew from the study because 0 12 of EPS, 4 patients taking haloperidol and 1 patient taking a © Copyright 2000 Physiciansmg/d placebo Postgraduate withdrew due to EPS. Press, The Barnes Inc. Rating Scale –1 for Drug-Induced Akathisia revealed substantial superior- 75 3 mg/d 150 ity for quetiapine at day 42 in the Peuskens and Link trial. Mean Change From Baseline Mean Change From mg/d 300 Quetiapine users had a low incidence of treatment- –2 mg/d600 750 9 Improved mg/d mg/d emergent EPS. Small et al. investigated the effects of low doses (≤ 250 mg/day) and high doses (≤ 750 mg/day) of aData from reference 2. quetiapine and placebo in 286 patients with a DSM-III-R diagnosis of chronic or subchronic schizophrenia. The re- searchers found that quetiapine did not induce EPS. to acetylcholine through muscarinic receptors, and so, as Borison et al.10 conducted a 6-week, double-blind, with diphenhydramine, quetiapine functionally decreases placebo-controlled trial of 75 to 750 mg/day of quetiapine the amount of activation or acetylcholineOne personal predominance copy mayin 109be printedpatients with a DSM-III-R diagnosis of acute associated with EPS—potentially a major advantage for chronic or subchronic schizophrenia. They found that pa- quetiapine over currently available antipsychotics. tients treated with quetiapine in the dose range studied Histaminic blockade is also linked to weight gain, failed to experience EPS. The serotonergic activity of que- which can be a serious adverse effect of quetiapine. In the tiapine may also be responsible, in large part, for the 3- to 6-week placebo-controlled clinical trials, 23% of drug’s antipsychotic properties, although this connection quetiapine-treated patients met a weight gain criterion of remains controversial.6 7% or more of body weight compared with 6% of the patients taking a placebo.5 Dopaminergic Quetiapine blockade of the dopaminergic (D2) receptor α 1-Adrenergic (IC50 = 329 nM)—combined with the histaminic and Like histaminic blockade, quetiapine blockade of the serotonergic effects of the drug—results in no reported α 4,6 1-adrenergic (A1) receptor (IC50 = 94 nM) also causes cases of dystonias, parkinsonian symptoms, or akathisia. somnolence at a rate of 7% and dizziness at a rate of 6%. This low affinity for the D2 receptor—2% when methyl- In addition, this blockade causes some orthostatic hypo- spiperone11 is used as a ligand in positron emission tomog- tension. In adults, orthostatic hypotension is reported as raphy (PET) studies and 20% to 50% when raclopride is dizziness in 6% of patients; in the elderly, the rate can be used12—is considerably less with therapeutic doses of que- 20% or greater. Dizziness is not always caused by ortho- tiapine than with the traditional antipsychotic drugs, a static hypotension. It is found in many patients taking property shared with clozapine. atypical antipsychotics in the absence of orthostatic hypo- The low affinity of quetiapine for the D2 receptor may tension. More than 20% of elderly patients receiving que- have some very important implications that have not yet tiapine—usually in doses of 100 to 200 mg/day—show an been suggested by the clinical data. Quetiapine has less af- increase in heart rate of 20 beats per minute or greater or a finity for the D2 receptor than does dopamine itself. With decrease in systolic blood pressure of 30 mm Hg or pulsatile release of dopamine into the synapse, Seeman et 13 greater. Orthostatic hypotension needs to be watched very al. have suggested that the blockade of D2 receptors by carefully in older persons because falls attributable to or- quetiapine is intermittent, at best, when it occurs and that thostatic hypotension, combined with age-related bone quetiapine is displaced from the receptor with each volley loss, can lead to bone fractures.7 of dopamine released into the synapse. If so, that fact is important in terms of EPS. Ultimately, this intermittent Serotonergic blockade may also be very important with respect to tar- Quetiapine blockade of the serotonergic (5-HT2A) re- dive dyskinesia. Currently, we lack data on quetiapine in ceptor (IC50 = 148 nM), along with the histaminic activity, tardive dyskinesia. 6 contributes to the EPS-inhibiting effects of the drug. The Quetiapine, with its very low or very temporary D2 oc- rate of EPS in patients taking quetiapine is very low. cupancy, produces no prolactin elevation. Arvanitis et al.2 32 J Clin Psychiatry 2000;61 (suppl 8) Quetiapine Side Effects found, in their fixed-dose study, that no dose of quetiapine reported substantial weight gain in up to 23% of patients. produced greater levels of prolactin elevation than placebo More clinical trials are needed to explore the properties of or haloperidol.

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