What is Abilify?

Abilify (generic name aripiprazole) was approved for the treatment of schizophrenia on November 15, 2002 by the U.S. Food and Drug Administration. It represents a departure from the usual mechanism of action of antipsychotic drugs.

How is Abilify different from other antipsychotic medications?

All of the currently available medications for schizophrenia block the ability of the neurotransmitter dopamine to bind to a particular receptor in the brain called the D2 receptor. The new, so-called atypical antipsychotic drugs like Zyprexa and Risperdal are weaker D2 receptor blockers than the older drugs like Haldol and Thorazine. By contrast, Abilify actually has the ability, under certain circumstances, to stimulate the D2 receptor and is technically called a "partial D2 agonist." Animal studies suggest that when levels of dopamine in the brain are low, Abilify may enhance the dopamine effect by stimulating the D2 receptor. On the other hand, these animal studies suggest that when dopamine levels in the brain are too high, Abilify may actually switch its role and block the ability of too much dopamine to get to the receptor. Because it is now believed that some of the negative and cognitive symptoms of schizophrenia may be due to too little dopamine while the positive symptoms like hallucinations and delusions are due to too much dopamine, a drug that could regulate dopamine activity in this way would be beneficial. However, it is very important to remember that we do not know if Abilify actually works in this way in the human brain.

Like the atypical antipsychotic drugs, Abilify also has effects on some of the serotonin receptors. Again, it is not yet clear if this is important in terms of how these drugs work in treating schizophrenia.

Abilify was studied in 1,238 patients with an acute relapse of schizophrenia before the FDA approved it. In these studies, Abilify proved to be superior to placebo for treating positive and negative symptoms.

What are the side effects of Abilify?

Abilify showed a relatively low rate of adverse side effects in the clinical trials. The most common side effects were headache, anxiety, and insomnia. Some patients also experience a reduction in blood pressure when they get up from lying or sitting, a phenomenon called "orthostatic hypotension." This can cause dizziness and lightheadedness. In the short term trials lasting four to six weeks the incidence of extrapyramidal side effects (EPS) from Abilify was low and there was no weight gain. However, longer-term experience is needed before it can be certain that these will not be problems with Abilify as they are with many other antipsychotic drugs.

What is the standard dosage of Abilify?

Abilify can be given once daily, at any time of day. It comes in 10, 15, 20 and 30 mg doses. The usual starting dose is 10 mg and most patients so far have been treated at between 10 and 15 mg daily. There are a few interactions between Abilify and other drugs, such as fluoxetine (Prozac) and paroxetine (Paxil), so it is important to tell your doctor about all the other drugs you are taking before starting Abilify.

Reviewed by Jack Gorman, M.D., (Feb. 2003)