Quetiapine is the name of a drug used to treat mental illness. It belongs to the group of atypical neuroleptics.
What is quetiapine?
Quetiapine is the name given to an atypical neuroleptic. This group of drugs is primarily used to treat bipolar disorder and schizophrenia. Quetiapine also has the advantage of being a second-generation antipsychotic, which means it has fewer undesirable side effects. Quetiapine was developed in the 1990s by the international pharmaceutical company AstraZeneca. This involved a further development of the first generation of typical neuroleptics. Quetiapine was approved in the USA in 1997. Shortly thereafter, European countries followed suit. After the expiration of the quetiapine patent in 2012, numerous generics were released. In Germany, the atypical neuroleptic is on the market under the trade name Seroquel. Because quetiapine is subject to prescription, a prescription must be presented at the pharmacy.
Pharmacologic action
Among the most important messengers between the human brain and neurons is dopamine. The release of the neurotransmitter causes downstream neurons to receive signals through receptors that serve as docking sites. These are the ability to remember things, to be happy, to be motivated or to make purposeful movements. When there is an excess of dopamine, however, there is a risk of problems ranging from manic joy to schizophrenia to loss of reality. Quetiapine, among other medications, is used to treat these dopamine-related mental symptoms. The atypical neuroleptic binds the dopamine receptors in the brain without activating them. In this way, a blockade takes place, which ensures a decrease in dopamine to normal levels. However, one disadvantage of quetiapine is that the drug also occupies the receptors of adrenaline and noradrenaline. This, in turn, creates a risk of side effects such as low blood pressure and drowsiness. Following its absorption, metabolism of quetiapine occurs entirely within the liver. The breakdown products of the drug also exhibit antipsychotic effects. Approximately 50 percent of the neuroleptic drug has left the organism after about seven hours. Excretion of quetiapine occurs 75 percent in the urine and 25 percent in the stool.
Medical use and application
For use, quetiapine is used in the treatment of psychosis. These include, in particular, schizophrenia, bipolar disorders, and manic illnesses. In addition, the drug has an alleviating effect on states of agitation, anxiety disorders, and depression. Quetiapine cannot completely counteract depressive or manic phases. However, the drug is considered useful in preventing relapses. While higher doses of the neuroleptic are administered as part of acute treatment, the dose is lowered during longer therapy. Quetiapine is usually taken in tablet form. Patients usually take retard tablets, which release the active ingredient with a delay. This allows a stable blood level to be achieved. The dosage of quetiapine depends on the respective indication. In all cases, treatment is started gradually. This means that the patient initially receives only smaller doses, which are then gradually increased over the course of therapy until the desired effect develops. During maintenance therapy, the doctor reduces the amount of the active substance to the lowest reasonable dose. Quetiapine is taken once or twice a day, regardless of meals. It is important to adjust the dose to the individual patient.
Risks and side effects
The use of quetiapine may be associated with adverse side effects, although not every patient experiences them. In most cases, side effects include headache, drowsiness, drowsiness, increase in weight, increased cholesterol levels, decrease in HDL cholesterol, increase in triglyceride levels, tachycardia (accelerated heartbeat), dry mouth, runny nose, constipation, nausea, vomiting, leukopenia (lack of white blood cells), and increased blood sugar levels.Occasionally, tics or twitching, type 2 diabetes mellitus, seizures, rashes on the skin, itching, angioedema, or fainting also occur. If malignant neuroleptic syndrome occurs as a result of taking quetiapine, therapy should be discontinued immediately. Quetiapine must not be used if the patient is hypersensitive to the active substance. Because intensive metabolism of the substance takes place in the liver, no other drugs may be taken in which the same metabolism takes place. These drugs include HIV-1 protease inhibitors, the antidepressant nefazodone, the antifungal agent ketoconazole, and the antibiotics clarithromycin and erythromycin. A careful risk-benefit assessment by the physician is necessary in the case of impaired liver function, diabetes, seizures, low blood pressure, severe cardiovascular diseases and after a stroke. In this case, the dosage must be as low as possible. In addition, the functions of the organs and the blood count must be checked regularly. Quetiapine should not be administered to elderly people suffering from dementia-related psychosis. Thus, there is an increased mortality rate in them during therapy. Quetiapine should also not be taken during pregnancy and breastfeeding. It has not been shown to be safe for use in mothers and children. In addition, there is an increased risk to the unborn child due to side effects such as movement disorders in the last third of pregnancy.
