Geodon
Geodon (generic name: Ziprasidone) is an oral and injectable drug that is used for treating psychoses, for example, schizophrenia. Although the mechanism of action of ziprasidone is not known, like other anti-psychotics, it inhibits communication between nerves of the brain. It does this by blocking receptors on the nerves for several neurotransmitters, the chemicals that nerves use to communicate with each other. It is thought that the beneficial effect of Geodon is due to its blocking of dopamine and serotonin receptors. It also inhibits the re-uptake of serotonin and norepinephrine by nerves in the brain like some anti-depressant drugs. Ziprasidone is associated with little or no weight gain, a feature that distinguishes it from other anti-psychotic drugs. Similarly, ziprasidone is unique among anti-psychotic drugs in that it does not increase cholesterol levels. The FDA approved ziprasidone as a treatment for schizophrenia in February, 2001.
Geodon Ziprasidone has a modest effect on the electrical activity of the heart which can be seen on the electrocardiogram (EKG) as a prolongation of the QT-interval. (See discussion below.) Other drugs which also affect the QT interval can add to the effects of ziprasidone and lead to serious disturbances in the rhythm of the heart. Due to the potential for such additive effects on the QT interval, ziprasidone should not be taken with thioridazine (Mellaril), quinidine (Quinidex), moxifloxacin (Avelox), pimozide (Orap), sotalol (Betapace), dofetilide (Tikosyn), and sparfloxacin (Zagam).
Carbamazepine (Tegretol) increases the body’s ability to eliminate ziprasidone and, therefore, may reduce the levels and lessen the effectiveness of ziprasidone. Conversely, ketoconazole (Nizoral) reduces the body’s ability to eliminate ziprasidone and may cause increases in levels of ziprasidone and more side effects. Ketoconazole does this by blocking the enzyme that eliminates ziprasidone, cytochrome P450 3A4. Other drugs that also block this enzyme and may increase the levels of ziprasidone include itraconazole (Sporanox), fluconazole (Diflucan), erythromycin, clarithromycin (Biaxin), nefazodone (Serzone), verapamil (Calan, Isoptin, Verelan), and diltiazem (Cardizem, Tiazac, Dilacor).
Geodon side effects
Some of the most common side effects associated with ziprasidone are feeling unusually tired (1 in 7 patients), nausea (1 in 10), constipation (1 in 11), dizziness (1 in 12), restlessness (1 in 12), diarrhea (1 in 20), rash (1 in 20), and a condition with abnormal muscle movements, including tremor, shuffling, and uncontrollable movements (1 in 20).
There is a slight risk (1 in 1500 patients) that ziprasidone by itself could significantly increase the QT interval. There is an even smaller risk (1 in 4000 patients) that it could cause a potentially serious change in the rhythm of the heart.
Geodon causes orthostatic hypotension, a drop in blood pressure upon rising that can cause dizziness or light-headedness. The risk is about 1 in 200 patients.
Geodon frequently causes tiredness (1 in 7 patients). Therefore, care should be exercised in any activity requiring mental alertness, such as operating a motor vehicle (including automobiles) or operating hazardous machinery. Less common side effects include seizures (1 in 250 patients).
As with other antipsychotics, long-term use of ziprasidone may lead to a potentially irreversible condition called tardive dyskinesia (involuntary movements of the jaw, lips, and tongue).
A potentially fatal complex referred to as Neuroleptic Malignant Syndrome (NMS) has been reported with other anti-psychotic drugs. Patients who develop NMS may have high fevers, muscle rigidity, altered mental status, irregular pulse or blood pressure, rapid heart rate, excessive sweating, and heart arrhythmias.
Although there is no clear link between ziprasidone and diabetes, patients should be tested during treatment for elevated blood-sugars. Additionally, persons with risk factors for diabetes, including obesity or a family history of diabetes, should have their fasting levels of blood sugar tested before starting treatment and periodically throughout treatment to detect the onset of diabetes. Any patient developing symptoms that suggest diabetes during treatment should be tested for diabetes.
Pharmacy Author: Emmanuel Saltiel, Pharm. D.
Medical Editor: Jay M. Marks, M.D.