Category Archives: Antipsychotics

Second generation antipsychotics for schizophrenia: SECOND GENERATION ANTIPSYCHOTICS(6)

Preliminary work in the area of first-episode psychosis in a small (n=22) open-label trial suggested that risperidone was effective in ameliorating both positive and negative symptoms as well as possibly improving cognitive function . Included in this study were treatment-naive patients with schizophrenia with episodes of less than five years on average. A more precise estimate of the value of risperidone in first-episode psychosis is anticipated when the longitudinal, randomized, controlled trial of risperidone versus haloperi-dol in this population is completed.

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Second generation antipsychotics for schizophrenia: SECOND GENERATION ANTIPSYCHOTICS(5)

SECOND GENERATION ANTIPSYCHOTICS(5)

Risperidone is associated with fewer EPSs than the conventional agents, haloperidol in particular. Its side effect profile differs from that of the other second generation agents. It does not block muscarinic receptors and, consequently, the rates of anticholinergic side effects, including confusion, are relatively low. Its most common adverse effects include anxiety, agitation, insomnia, headache and weight gain. buy flovent inhaler

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Second generation antipsychotics for schizophrenia: SECOND GENERATION ANTIPSYCHOTICS(4)

Risperidone Not long after clozapine resurfaced, risperidone was developed following the observation that ritanserin (a serotonin 5-HT2A,2B,6,7 receptor antagonist) improved negative symptoms and reduced the incidence of EPS when added to conventional antipsychotics . Risperidone blocks both 5-HT2 and D2 receptors, with a 20-fold higher binding affinity for 5-HT2 over D2. Several short term studies in patients with chronic schizophrenia have shown equal and greater improvement in positive and negative symptoms, respectively, compared with conventional agents. However, the advantage regarding negative symptoms is not consistent among trials and was not demonstrable in a recent meta-analysis. buy ortho tri-cyclen online

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Second generation antipsychotics for schizophrenia: SECOND GENERATION ANTIPSYCHOTICS(3)

SECOND GENERATION ANTIPSYCHOTICS(3)

Results of studies to date assessing an adequate trial duration of clozapine conflict. Early recommendations were to treat patients for six months at a therapeutic dose before considering it ineffective . However, Conley et al have reported that lack of response at eight weeks predicts a similar outcome at six months. At this time, a three- to six-month trial is recommended considering that clozapine is reserved for patients failing to respond to first line treatment and the lack of other effective alternatives. birth control pills

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Second generation antipsychotics for schizophrenia: SECOND GENERATION ANTIPSYCHOTICS(2)

However, there is no consensus of the types of antipsychotics [eg, one novel and one conventional versus two novels versus two conventionals] or the dosing and duration of each trial). In this population, both positive and negative symptoms have been shown to improve more significantly with clozapine than with conventional antipsychotics. However, the advantage for negative symptoms has not always been observed and has come under scrutiny more recently. Other important effects of clozapine use are its apparent reduction in risk for suicide and beneficial effects on persistent aggression in schizophrenia. buy ampicillin

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Second generation antipsychotics for schizophrenia: SECOND GENERATION ANTIPSYCHOTICS(1)

ATYPICALITY

The term ‘atypical’ was originally applied to clozapine because it was unrelated to previous antipsychotic agents chemically and in its effects in animal models . Currently, ‘atypicals’ are defined as antipsychotics with the following characteristics: greater improvement in negative symptoms over conventional agents; minimal to no risk of EPS/TD; minimal to no effect on serum prolactin levels; and minimal to no potential for provoking catalepsy in rats . Although commonly used, this term does not strictly apply to each of the second generation antipsychotics. It is thought that the greater affinity for 5-HT2 compared with D2 receptors may account for these agents’ atypicality; however, some conventional antipsychotics also share similar serotonin and dopamine binding profiles (ie, loxapine, thioridazine and chlorpromazine) . In addition, the newer compounds are a heterogeneous group with distinguishing pharmacological and clinical features. The pharmacological profiles are illustrated in Table 2, and the relevant clinical features are described in the section entitled ‘Second generation antipsy-chotics’. Table 2 can be used by clinicians to both predict and explain benefits and adverse effects by correlating their understanding of receptor functions and pharmacological effects. buy diabetes drugs

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Second generation antipsychotics for schizophrenia: HISTORY OF PHARMACOTHERAPY AND HYPOTHESES(2)

HISTORY OF PHARMACOTHERAPY AND HYPOTHESES(2)

This led to the emergence of the dysregulation hypothesis, which suggests that dopaminergic pathways are not in homeostatic balance, leading to hyperactivity in certain regions of the brain and hypoac-tivity in others. In general, serotonin activity has an inhibitory effect on dopaminergic pathways. The dysregula-tion theory has been broadened by postulating a D2/5-hydroxytriptamine (5-HT2) imbalance, with positive symptoms resulting from an increase in the D2/5-HT2 activity ratio in the mesolimbic region of the brain and negative symptoms from a decrease in the ratio in the frontal cortex . Other neurochemicals such as glutamate and acetylcholine are being studied with respect to their role in the etiology of schizophrenia . Research is now focusing on alternate mechanisms of action than those of the conventional agents, attempting to develop antipsychotics without EPS while improving response rates and ameliorating negative symptoms and cognitive deficits. These research endeavors have given rise to a new category of agents commonly referred to as the atypical, second generation or novel antipsychotics, or serotonin-dopamine antagonists(Table 1). levitra super active plus

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Second generation antipsychotics for schizophrenia: HISTORY OF PHARMACOTHERAPY AND HYPOTHESES(1)

Recognizing that these agents, the neuroleptics, were all variably potent antagonists of dopamine receptors, the dopamine hypothesis of schizophrenia was promoted . Subsequent to the identification of dopamine receptor subtypes (now subclassified as D1 to D5), the dopamine theory was refined with the D2 receptor becoming the focus until more recently. D2 receptor blockade in the limbic system of the brain is believed to be associated with effect on positive symptoms. The major drawbacks of these conventional agents, extrapy-ramidal side effects (EPS), tardive dyskinesias (TD) and hyperprolactinemia, also result from D2 blockade, but in regions distinct from the limbic system. Such drug-induced abnormal movements can significantly limit the acceptability of these medications. In addition, approximately 30% to 50% of patients do not respond or are only partially responsive to conventional agents with negative and cognitive symptoms often persisting. buy prednisone

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Second generation antipsychotics for schizophrenia

Second generation antipsychotics for schizophrenia

Schizophrenia is a chronic nniess affecting 1% of the population and remains one of the most severe and disabling diseases in existence. Symptoms can be clustered into two major groups – positive and negative – however, cognitive deficits and mood symptoms often coexist. ventolin inhalers

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