Quetiapine Case Studies

that this drug's antipsychotic activity is mediated through a combination of dopamine type 2 (D2) and serotonin type 2 (5-HT2) antagonism. It is an antagonist at multiple neurotransmitter receptors in the brain: Serotonin 5-HT1A and 5-HT2, dopamine D1 and D2, histamine H1, and adrenergic alpha1- and alpha2-receptors; but appears to have no appreciable affinity at cholinergic muscarinic and benzodiazepine receptors. Norquetiapine, an active metabolite, differs from its parent molecule by exhibiting high affinity for muscarinic M1 receptors. Antagonism at receptors other than dopamine and 5-HT2 with similar receptor affinities may explain some of the other effects of quetiapine. The drug's antagonism of histamine H1-receptors may explain the

Another 5-HT2A and 5-HT2C antagonist with high affinity for dopamine receptors is the therapeutically used atypical antipsychotic clozapine. Its significant clinical advantage is its reduced incidence of extrapyramidal symptoms relative to first generation typical antipsychotics (Sansone, 2014).

The major support and refutation of the dopamine hypothesis has come from the examination of dopamine receptors in these regions of the brain. There are two main types of dopamine receptors, D1 and D2. However, within the category of D2 receptors, there are three subtypes, D2, D3, and D4. (5) Through PET scan analysis of dopamine usage in the brain and post-mordum molecular analysis of brain tissue, researcher were able to determine relative levels of dopamine receptors in patients with schizophrenia compared to non-schizophrenics. Overall analysis of dopamine

The main criticism of an imbalance of neurotransmitters being the cause of schizophrenia is the finding that antipsychotics block receptors within a day or two, although it takes several weeks for them to take full affect (Wickens, 2005). This suggests that the key factor in improvement is not the

The vast majority of medications currently in the marketplace or under development to treat schizophrenia/psychosis focus on dopamine in one way or another. Most of the medications that are currently used to treat this condition affect dopamine in a direct way. These drugs specifically target this substance because historically, psychosis has been linked to unusually high levels of dopamine in the part of the brain that is known as the stratum (Nauert, 2010). Moreover, there is a fair amount of research that indicates there is a direct correlation between levels of glutamate, which is another substance the brain produces and is found in the hippocampus, and dopamine in individuals who eventually develop schizophrenia.

The adverse effects of drug-drug interactions in patients with schizophrenia and bipolar disorder can be severe and depends mainly on the pharmacokinetic properties of the drug. Both the distances between drug targets and the comparison of target neighbors are important when when administering olanzapine in combination with other drugs due to its effects on the CNS. To avoid severe adverse effects such as sedation, orthostatic hypotension, tachycardia or transaminase the prescribing drugs in combination such as olanzapine with fluvoxamine or diazepam should be therapeutically monitored while drugs such as sertraline will not cause adverse effects. (Spina, E., de Leon, J., (2007)).

Antipsychotics are medications that physicians use to treat psychotic disorders such as Schizophrenia, Delusional disorder, Paraphrenia, and Substance-induced psychotic disorders. These disorders are characterised by the patient’s inability to make good judgments, think with a clear head, communicate effectively, relate to society, and understand reality. Antipsychotic drugs are also useful in the treatment of bipolar conditions that involve extreme cases of manic behaviour. Examples of these drugs include Thorazine and Trilafon. These drugs belong to a drug class called phenothiazines. They work by changing the actions of chemicals in the brain. The drugs can be beneficial, however, Steen et al. (2014) argue that the medicines have several harmful effects such as changes

For the past fifty years treatment of schizophrenia has been marked by its basis on the dopamine hypothesis for schizophrenia. However, this model for the disease and its subsequent treatment have left many patients without relief or help in dealing with this disease which has lead to a search for a better model. The dopamine model lacks the recognition of a whole range of symptoms associated with the disease and therefore can not be an accurate basis for treatment. More recently, there has been a shift to the glutamate hypothesis which has been shown to more accurately characterize the wide range of symptoms experienced by patients living with this disorder as well as the possibility in improvements for drug treatments.

Over the years, experiments have produced evidence to suggest that dopamine plays a role in the development of Schizophrenia (Howes, McCutcheon, & Stone, 2015). Dopamine is a neurotransmitter that is produced in the substantia nigra and ventral tegmental regions of the brain. The belief that dopamine was involved in Schizophrenia arose after multiple studies performed with compounds produced an increase in extracellular concentrations of dopamine (Lieberman, Kane, & Alvir, 1987). The patients that were administered these compounds had similar symptoms to those observed from patients who were diagnosed with Schizophrenia (Lieberman et al., 1987).

Antipsychotics are generally used to treat psychosis in mental disorders. These disorders include schizophrenia and bipolar disorder (Thyssen et al., 2010). Risperidone is known as an atypical second generation antipsychotic and used in the treatment of a multitude of disorders. This medication can often challenge behavioral problems that are associated with schizophrenia, autism spectrum disorder, bipolar disorder, or attention deficit hyperactivity disorder (Schatzberg & Nemeroff, 2013). It is important for the prescriber to be aware of the side effect and any possible adverse reactions that may occur. There can be many detrimental side effects that someone may not enjoy,

Haloperidol is one of the choice treatments for treating MAP. Haloperidol is also an aggressive dopamine blockade (antagonist) which has been hypothesized to worsen craving and reduces motivation to continue medication and which may lead to a high chance of a drug relapse. Quetiapine targets dopamine D2 and serotonin 5-HT2A receptors and therefore may have fewer side effects that may lead to a lower risk of drug relapse. “The aims of this study were to compare the antipsychotic and adverse events of quetiapine, an atypical antipsychotic drug, to haloperidol, a standard treatment for primary psychotic disorder, in individuals with MAP.” It is hypothesized that overall Quetiapine may be a better option for treating MPA because it may help

While the main action of typical antipsychotics is on the D2 receptor, atypical antipsychotics show enhanced activity at 5-HT receptors with a low affinity for D2 receptors (Divac et al., 2014). Atypical antipsychotics are more effective in reducing cognitive and negative symptoms and result in fewer EPS than the typical antipsychotics (Davis, Chen, & Glick, 2003). The high binding affinity

Schizophrenia is a mental disorder characterized with severe, chronic, and potentially disabling thought disorder (American Psychiatric Association, 2013). Antipsychotic drugs are the primary use of treatment for schizophrenic disorders (Kane, 1987). Some of the common used psychotropic medications used to treat schizophrenia are: haloperidol, risperidone, aripiprazole, olanzapine, trifluoperazine, perphenazine, quetiapine, thioridazine, chlorpromazine, and clozapine. Antipsychotics like FGAs and SGAs are can be administered orally, in the form of a pill or liquid, or intravenously, by injections. Like with oral forms of antipsychotics, injections offer side effects too. These side effects vary but are very much alike to those of the matching drugs in oral form, though added mild or infrequent injection-related side effects can occur such as: pain, skin thickening, and nodules (Haddad & Fleischhacker, 2011). Antipsychotics administered by injection is one approach to managing nonadherence, although this approach does not work for all patients. Additionally, a proportion of patients who start on injections, later, do not continue with treatment. One study found more than half of patients who began risperidone (Risperdal) injections, stopped after 6 months of treatment (Taylor et al., 2004). With injections, patient nonadherence can be due to the personal characteristics, dosage range, initial startup, administration of the drug, and monitoring. The dosage range for each

Antipsychotics are classified as major tranquilizers that are used to treat mental health illnesses such as schizophrenia, bipolar disorder, and other mental illnesses. They can also treat severe depression and severe anxiety. These antipsychotics drugs reduce or increase the effect of neurotransmitters in the brain to regulate levels that help transfer information throughout the brain. The neurotransmitters that are affected are the serotonin, dopamine, and noradrenaline.

For the treatment of bipolar disorder, antipsychotic medicines are sometimes prescribed to treat episodes of mania or hypomania. Examples of antipsychotic medicines include: aripiprazole, olanzapine, quetiapine and risperidone. These drugs may also be used as a long-term mood stabiliser and quetiapine can be used for the treatment of bipolar depression in the long-term. Antipsychotic medicines can be particularly useful if symptoms are severe or behaviour is disturbed. As there is a chance that the antipsychotics could cause side effects, the initial dose will usually be low. These side effects could include weight gain, blurred vision, constipation and dry mouth. If prescribed an antipsychotic medicine, regular health checks will be required at least every three months. If the symptoms don 't improve, the patient may be offered lithium and valproate as well.