Antipsychotics are medications used to treat psychotic behavior such as delusions (strong, false beliefs) and hallucinations (experiences that people can feel, hear, and see but are not real) that may sometimes develop in patients with Huntington’s disease.

Antipsychotics may also be used to manage movement symptoms such as chorea (involuntary movements) and behavioral issues such as irritability in Huntington’s disease.

How antipsychotics work

There are two major classes of antipsychotics: typical and atypical antipsychotics. The exact way in which these medications work in Huntington’s disease is not well known. However, it is thought that both types work by acting on the dopamine D2 receptor, reducing the effect of dopamine in the brain.

Dopamine is a chemical messenger, and its overactivity is thought to cause psychotic symptoms.

First- and second-generation antipsychotics differ in that the latter also interacts with 5HT2A receptors, or proteins that facilitate the action of another neurotransmitter in the brain known as serotonin. Psychotic symptoms are also thought to be linked to 5HT2A receptor activity.

Examples of antipsychotics used in Huntington’s

Haldol (haloperidol) is a first-generation antipsychotic used in Huntington’s. Abilify (aripiprazole), Clozaril (clozapine), Zyprexa (olanzapine), Seroquel (quetiapine), Geodon (ziprasidone), and Risperdal (risperidone) are examples of second-generation antipsychotics.

Taking antipsychotics

All antipsychotics are associated with adverse effects such as drowsiness, dizziness, postural hypotension (low blood pressure when standing from a sitting or lying position), irregular palpitations, sexual dysfunction, and sudden cardiac arrest.

First-generation antipsychotics are more likely to cause a collection of side effects known as extrapyramidal symptoms. These include symptoms that resemble Parkinson’s disease (muscle rigidity, tremors, and slowed movements), dystonias (muscle contractions causing unusual twisting of parts of the body, most often the neck), dyskinesias (repetitive, involuntary, and purposeless body or facial movements), and akathisias, also known as restless legs syndrome.

Second-generation antipsychotics more commonly cause metabolic side effects such as weight gain, higher cholesterol, and elevated blood sugar that may result in diabetes.

Because of these side effects, patients on antipsychotics are often closely monitored and may be required to undergo regular tests to ensure that medication levels are within safe ranges.

Antipsychotics should be taken regularly. It takes about six months of consistent medication before symptoms start improving.


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