Ziprasidone



Definition

Ziprasidone is a drug used to treat schizophrenia . It is available with a prescription under the brand name Geodan.

Purpose

Ziprasidone is in a class of drugs called antipsychotics. It is used to control symptoms of schizophrenia.

Description

The United States Food and Drug Administration approved ziprasidone for treatment of schizophrenia in 2001. Mental well-being is partially related to maintaining a balance between naturally occurring chemicals in the brain called neurotransmitters . Ziprasidone is thought to modify the actions of several neurotransmitters and in this way restore appropriate function to chemical systems in the brain that are out of balance in people with schizophrenia.

Recommended dosage

The dosage of ziprasidone varies widely from one individual to another. A common initially dosage is 20 mg of ziprasidone taken twice daily. The dosage is gradually increased until symptoms of schizophrenia subside. Dosages of up to 100 mg may be taken twice daily. Ziprasidone should be taken with food.

Precautions

Ziprasidone may alter the rhythm of the heart. Because of the risk of irregular heartbeats or even death, it should not be taken by people with a history of irregular or prolonged heart rhythms (long QT syndrome), those with heart failure, or individuals who have recently had a heart attack. People with a history of heart disease should discuss the risks and benefits of treatment with their doctor before starting ziprasidone. Ziprasidone may lower blood pressure to dangerously low levels, causing people to faint. It should not be taken by people who have slow heartbeats and those with low levels of potassium or magnesium in their blood.

Individuals with a history of seizure, even seizure brought on by drug or alcohol abuse, should use ziprasidone cautiously and with close physician supervision, because it may increase the tendency to have seizures .

Ziprasidone may increase body temperatures to dangerously high levels. People who exercise strenuously, those exposed to extreme heat, individuals taking drugs with anticholinergic effects (this includes many common antidepressants), and persons prone to dehydration, should use the drug cautiously and be alert to dehydration-related side effects. Elderly persons with increased risk of developing pneumonia should be carefully monitored while taking ziprasidone. Because there is a high incidence of suicide in all patients with psychotic illnesses, people using ziprasidone should be observed carefully for signs of suicidal behavior. Women who are pregnant or breast-feeding should not take ziprasidone.

Side effects

The most common reason that ziprasidone is stopped is due to development of a rash. Another common side effect is drowsiness. This side effect is usually worse when starting the drug and becomes less severe with continued use. People performing tasks that require mental alertness such as driving or operating machinery should refrain from doing so until they see how the drug affects them. Other side effects that may occur are abnormal, involuntary twitching (5%), and respiratory disorders (8%). Nausea, constipation, indigestion, and dizziness due to low blood pressure occur in more than 5% of people taking ziprasidone.

Other, less common, side effects are rapid heartbeats, low blood pressure, agitation, tremor, confusion, amnesia , dry mouth, increased salivation, joint pains, and abnormal vision.

The incidence of some adverse effects such as low blood pressure, anorexia, abnormal involuntary movements, sleepiness, tremor, cold symptoms, rash, abnormal vision, dry mouth or increased salivation appears to increase at higher dosages.

People taking ziprasidone should alert their health care provider immediately if they develop a rash or hives since this could indicate a potentially serious adverse reaction. Patients should also notify their health care provider immediately if they experience any abnormal involuntary muscle movements. People who think they may be experiencing any side effects from this or any other medication should talk to their physicians.

Interactions

Ziprasidone interacts with many other drugs. It is a good idea to review all medications being taken with a physician or pharmacist before starting this drug. Since ziprasidone may alter the rhythm of the heart, people who are also taking drugs such as quinidine, dofetilide, pimozide , sotalol, erythromycin, thioridazine , moxifloxacin, and sparfloxacin should not take it. These drugs may also affect properties of the heart and taken with ziprasidone increase the risk of irregular heart rhythms and other cardiac problems. Because ziprasidone causes sleepiness, it should be used sparingly and with care with other drugs that also have a tendency to make people drowsy such as antidepressants, antihistamines, some pain relievers, and alcohol. Ziprasidone may lower blood pressure to the point at which people feel dizzy or faint. People taking medication to regulate their blood pressure should have their blood pressure monitored and treatment modified as needed. Ziprasidone may also decrease the effects of drugs used to treat Parkinson's disease such as levodopa.

Other drugs taken in combination with ziprasidone may alter the effects of ziprasidone. For example, drugs such as carbamazepine , used to treat seizures, increases liver metabolism and may cause ziprasidone to be less effective. Alternatively, drugs such as ketoconazole slow liver metabolism and may increase negative side effects associated with ziprasidone.

Resources

BOOKS

Facts and Comparisons Staff. Drug Facts and Comparisons. 6th Edition. St. Louis: Facts and Comparisons, 2002.

Pfizer Staff. Geodan Package Insert. New York, New York: Pfizer Inc, 2001.

Kelly Karpa, RPh, Ph.D.



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