Ziprasidone

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Ziprasidone (Brand names: Geodon, Zeldox) is one of a new generation of drugs called atypical antipsychotics. Ziprasidone rebalances dopamine and serotonin to improve thinking, mood, and behavior.

It is used to treat schizophrenia and bipolar disorder.

Schizophrenia is a mental illness. It varies from person to person, but can involve:

  • hallucinations: the person sees, hears, feels, smells or tastes something that is not actually there; most commonly a person may hear voices
  • delusions: a delusion is a falsebbelief held by a person which is not held by others of the same cultural background
  • disturbed or disorganised thinking
  • poor memory and concentration
  • loss of emotion and expression
  • loss of motivation and energy
  • difficulty interacting with others, leading to social isolation.

Contents

[edit] BRAND NAMES

[edit] STRUCTURE

Ziprasidone.jpg

[edit] MECHANISM OF ACTION

Ziprasidone is an atypical antipsychotic. its efficacy in schizophrenia is mediated through a combination of dopamine type 2 (D2) and serotonin type 2A (5HT2A) antagonism.

Because ziprasidone inhibits serotonin (5-hydroxytryptamine; 5-HT) and noradrenaline (norepinephrine) reuptake, it may have anxiolytic and antidepressant effects as well.

The relatively weak antagonistic actions of ziprasidone on the α1-adrenergic and H1 receptors likely in part explain some of its side effects, such as sedation and orthostatic hypotension. Unlike many other antipsychotics, ziprasidone has no significant affinity for the mACh receptors, and as such lacks any anticholinergic side effects.

[edit] INDICATIONS

  • Oral formulation: treatment of schizophrenia, as monotherapy for the acute treatment of bipolar manic or mixed episodes, and as an adjunct to lithium or valproate for the maintenance treatment of bipolar disorder.
  • Intramuscular injection: acute agitation in schizophrenic patients.

In choosing among treatments, prescribers should be aware of the capacity of ziprasidone to prolong the QT interval and may consider the use of other drugs first

[edit] DOSAGE

Oral route: Give oral doses with food.

  • Schizophrenia: Initiate at 20 mg twice daily. Daily dosage may be adjusted up to 80 mg twice daily. Dose adjustments should occur at intervals of not less than 2 days. Safety and efficacy has been demonstrated in doses up to 100 mg twice daily. The lowest effective dose should be used.

[edit] CONTRAINDICATIONS

  • Do not use in patients with a known history of QT prolongation
  • Do not use in patients with recent acute myocardial infarction
  • Do not use in patients with uncompensated heart failure
  • Do not use in combination with other drugs that have demonstrated QT prolongation
  • Do not use in patients with known hypersensitivity to ziprasidone

[edit] WARNINGS AND PRECAUTIONS

  • QT Interval Prolongation: Ziprasidone hydrochloride use should be avoided in patients with bradycardia, hypokalemia or hypomagnesemia, congenital prolongation of the QT interval, or in combination with other drugs that have demonstrated QT prolongation.
  • Tardive Dyskinesia: May develop acutely or chronically
  • Neuroleptic Malignant Syndrome (NMS): Potentially fatal symptom complex has been reported with antipsychotic drugs. Manage with immediate discontinuation of drug and close monitoring.
  • Hyperglycemia and Diabetes Mellitus (DM): Any patient treated with atypical antipsychotics should be monitored for symptoms of hyperglycemia including polydipsia, polyuria, polyphagia, and weakness. When starting treatment, patients with DM risk factors should undergo blood glucose testing before and during treatment.
  • Rash: Discontinue in patients who develop a rash without an identified cause.
  • Orthostatic Hypotension: Use with caution in patients with known cardiovascular or cerebrovascular disease
  • Leukopenia, Neutropenia, and Agranulocytosis has been reported with antipsychotics. Patients with a pre-existing low white blood cell count (WBC) or a history of leukopenia/neutropenia should have their complete blood count (CBC) monitored frequently during the first few months of therapy and should discontinue ziprasidone hydrochloride at the first sign of a decline in WBC in the absence of other causative factors.
  • Seizures: Use cautiously in patients with a history of seizures or with conditions that lower seizure threshold
  • Potential for Cognitive and Motor impairment: Patients should use caution when operating machinery
  • Suicide: Closely supervise high-risk patients

[edit] INTERACTIONS

  • Ziprasidone should not be used in combination with other drugs that have demonstrated QT prolongation
  • The absorption of ziprasidone is increased up to two-fold in the presence of food
  • Given the primary CNS effects of ziprasidone, caution should be used when it is taken in combination with other centrally acting drugs.
  • Because of its potential for inducing hypotension, ziprasidone may enhance the effects of certain antihypertensive agents.
  • Ziprasidone may antagonize the effects of levodopa and dopamine agonists
    • CYP3A4 inducers (e.g. carbamazepine) are expected to decrease Ziprasidone concentrations
  • CYP3A4 inhibitors : CYP3A4 inhibitors like Ketoconazole, Itraconazole, Nefazodone, erythromycin, Clarithromycin, Isoniazid, fluvoxamine, Fluoxetine, and Grapefruit juice are expected to increase Ziprasidone concentrations.

[edit] PREGNANCY AND LACTATION

  • Pregnancy Category C (US): Ziprasidone should be used during pregnancy only if the potential benefit justifies the potential risk.
  • Nursing Mothers: Breast feeding is not recommended.

[edit] SIDE EFFECTS

Commonly observed adverse reactions: Somnolence and nausea.

[edit] RELATED LINKS

Antipsychotics (Typical and Atypical): pharmacology, indications and adverse effects

[edit] BIBLIOGRAPHY

[edit] REFERENCES