Medication used for schizophrenia Part 2
Choice of Drug
There are some differences between the various antipsychotic drugs. No one drug can be considered significantly better than the others, however one may be better for one individual than another. For example, some are more sedating than others so may be suitable for patients who are agitated or cannot sleep. If one does not work so well, a different one is tried until a good response occurs. A good response to antipsychotic medication occurs in about 70% of cases. Symptoms such as agitation and hallucinations generally ease within a few days of starting medication. Symptoms like delusions usually subside within a few weeks and it can take several weeks for full improvement. Antipsychotic medication is normally continued long-term once symptoms improve. Long term treatment aims to prevent relapses, or at least limit the number and severity of relapses. There is some evidence that the newer atypical antipsychotics have lower relapse rates than older typical antipsychotics. Newer atypical antipsychotics have been shown in studies to be more effective at improving cognitive function (including attention, memory, and speech) than older typical antipsychotics. Newer atypical antipsychotics also appear to be more effective than older typical antipsychotics for negative symptoms of schizophrenia. Clozapine should be tried for patients who have not responded adequately to treatment despite the use of adequate doses of at least two different antipsychotic drugs. At least one of the drugs should be an atypical antipsychotic before trying clozapine. Clozapine is very effective for psychotic symptoms including hallucinations and breaks from reality. Clozapine can sometimes cause a serious condition called agranulocytosis, a loss of the white blood cells which reduces the ability to fight infection. People who take clozapine must get their white blood cell counts checked weekly for the first 18 weeks and every two weeks after that for the first year and every four weeks thereafter, including the first four weeks after the drug is discontinued. Other atypical antipsychotics do not cause agranulocytosis. While all antipsychotics lower the threshold for seizures (making an epileptic fit more possible), this effect is more pronounced with clozapine. The risk of agranulocytosis and the cost of blood tests is the main reason that clozapine is generally reserved for when other medication fails which is estimated to be 30% of cases.
For patients who have only one episode of schizophrenia and who remain symptom free for two years with treatment, the medication may then be discontinued slowly; the patient should be closely monitored for relapse when medication is being discontinued.
To be continued next week
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