Amoxapine as an Atypical Antipsychotic: A Comparative Study Vs Risperidone

Abstract

Amoxapine is marketed as an antidepressant. However, its invitro profile, receptor occupancy and preclinical effects are very similar to atypical antipsychotics. Amoxapine has also shown efficacy as an atypical antipsychotic in open trials. The objective of this study was to compare the antipsychotic and side effect profile of amoxapine and risperidone in a randomised assignment, standardized dosing, doubleblind trial of acutely psychotic patients with schizophrenia. A total of 48 schizophrenic patients were enrolled and randomized in a double-blind 6-week trial to receive either risperidone (up to 5 mg/day) or amoxapine (up to 250 mg/day). Positive, negative, affective symptoms and motor side effects were measured using standardized weekly assessments. Prolactin levels were also determined at baseline and at the end of the study. A total of 39 patients (amoxapine, n ¼ 22; risperidone, n ¼ 21) completed the trial. Both pharmacological treatments, amoxapine 228.0 mg/day (SD ¼ 34.6) and risperidone 4.5 mg/day (SD ¼ 0.7), showed equivalent improvement in positive, negative, and depressive symptoms. Amoxapine was associated with less EPS and less prolactin elevation than risperidone. These data support previous reports about the efficacy of amoxapine as an atypical antipsychotic. Since amoxapine is off-patent, it may be a valuable low-cost alternative to new atypical antipsychotics, particularly in low-income countries where the majority of the patients are still treated with typical antipsychotics.

Almost All Antipsychotics Result in Weight Gain: A Meta-Analysis

“…For some AP, only 1 study was available, or data could not be used (sd or se could not be calculated) – these were therefore not included in the meta-analyses. The excluded AP and their weight change are amoxapine 1.05 kg (<6 wk, n = 22) [42], blonanserine 1.29 kg, sd = 3.48 (6–16 wk, n = 92) [43], fluphenazine −2.6 (16–38 wk, n = 9) [44], iloperidone 2.6, sd = 3.7 (<6 wk, n = 1239) [45], levomepromazine 4.1 (16–38 wk, n = 19) [46], lurasidone 0.9 kg (<6 wk, n = 90) [47], pimozide 2.9 (6–16 wk, n = 24) [48] and zuclopentixol 0.6 (6–16 wk, n = 19) [49]. The I-square of the included studies varied strongly, ranging from 10.3%–99.8% (in case 4 or more studies were included in the analysis), indicating little heterogeneity to very strong heterogeneity.…”

Hyperprolactinemia associated with psychotropics—a review

“…Amoxapine is an antidepressant with a receptor profile similar to that of neuroleptics (Anton et al ., 1983; Apiquian et al ., 2005). It increased prolactin levels significantly more than desipramine (Anton et al ., 1983).…”

“…It increased prolactin levels significantly more than desipramine (Anton et al ., 1983). In a comparison study of 39 patients with risperidone, amoxapine was found to have lower incidence of EPS and less prolactin elevation (Apiquian et al ., 2005).…”

Amoxapine Inhibits the Delayed Rectifier Outward K+ Current in Mouse Cortical Neurons via cAMP/Protein Kinase A Pathways

“…In systematic doubleblind trials, amoxapine was found to be of equal efficacy to that of an antidepressant and an antipsychotic (Anton and Burch, 1990). A recent study found that the antipsychotic activity of amoxapine was comparable with that of risperidone (Apiquian et al, 2005). Furthermore, because amoxapine is now off-patent and can be produced at generic prices, the drug could potentially rival other typical antipsychotics.…”

“…Because amoxapine is a relatively weak reuptake inhibitor, it was suggested that the molecule may have the properties of an atypical antipsychotic agent (Apiquian et al, 2005). The upper range of therapeutic plasma concentrations of amoxapine has been reported from 0.2 to 0.4 g/ml (0.637-1.912 M) in human body (Winek et al, 2001).…”