| Drug Index |
| GENERIC NAME : |
| estazolam |
| BRAND NAMES : |
| Prosom tablets (1 mg and 2 mg) |
| STREET NAMES : |
| downers, benzo’s, tranq’s |
| BRIEF DESCRIPTION : |
Estazolam is categorized as a central nervous system sedative/hypnotic (tranquilizer). It belongs to a class of drugs known as benzodiazepines, which are the most widely prescribed medications that affect central nervous system function. Independent of concentration, estazolam in plasma is 93% protein bound and is extensively metabolized. Only two metabolites (1-oxo-estazolam & 4 ? hydroxy ? estazolam) were detected in human plasma up to 18 hrs. The pharmacologic activity of estazolam is primarily from the parent drug and not its metabolites.
The elimination of the parent drug takes place via hepatic (liver) metabolism of estazolam to hydroxylated and other metabolites that are eliminated largely in the urine both free and conjugated. In humans, greater than 70% of a single dose of estazolam was recovered in the urine as metabolites. Less than 5% of a 2 mg dose of estazolam was excreted unchanged in the urine, with only 4% of the dose appearing in the feces. In vitro studies with human liver microsomes indicate that the biotransformation of estazolam to the major circulating metabolite 4-hydroxy-estazolam is mediated by cytochrome P450 3A (CYP3A). The range of estimates for the mean elimination half-life (the time it takes to eliminate half of the drug from the blood stream) of estazolam varied from 10 to 24 hours.
Estazolam is categorized as a central nervous system sedative/hypnotic (tranquilizer). It belongs to a class of drugs known as benzodiazepines, which are the most widely prescribed medications that affect central nervous system function. Independent of concentration, estazolam in plasma is 93% protein bound and is extensively metabolized. Only two metabolites (1-oxo-estazolam & 4- hydroxy-estazolam) were detected in human plasma up to 18 hrs. The pharmacologic activity of estazolam is primarily from the parent drug and not its metabolites.The elimination of the parent drug takes place via hepatic (liver) metabolism of estazolam to hydroxylated and other metabolites that are eliminated largely in the urine both free and conjugated. In humans, greater than 70% of a single dose of estazolam was recovered in the urine as metabolites. Less than 5% of a 2 mg dose of estazolam was excreted unchanged in the urine, with only 4% of the dose appearing in the feces. In vitro studies with human liver microsomes indicate that the biotransformation of estazolam to the major circulating metabolite 4-hydroxy-estazolam is mediated by cytochrome P450 3A (CYP3A). The range of estimates for the mean elimination half-life (the time it takes to eliminate half of the drug from the blood stream) of estazolam varied from 10 to 24 hours.
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| INDICATIONS FOR USE : |
| Estazolam (Prosom) is indicated for the short-term management of insomnia characterized by difficulty in falling asleep, frequent nocturnal awakenings, and/or early morning awakenings. Both outpatient studies and a sleep laboratory study have shown that estazolam administered at bedtime improved sleep induction and sleep maintenance. Because insomnia is often transient and intermittent, the prolonged administration of estazolam is generally neither necessary nor recommended. Since insomnia may be a symptom of several other disorders, the possibility that the complaint may be related to a condition for which there is a more specific treatment should be considered. |
| ABUSE AND ADDICTIVE POTENTIAL : |
| Estazolam is a short acting benzodiazepine and demonstrates potential for dependence (addiction). This is especially true in individuals with a history of drug addiction or alcoholism. In general, benzodiazepines should be prescribed for short periods of time. Extension of the treatment period should not take place without reevaluation of the need for continued therapy. Withdrawal can appear following cessation of recommended doses, even after using the medication less than 30 days. Generally speaking, the longer the medication is used and/or the higher the dose the more withdrawal symptoms may occur. Abrupt discontinuation should be avoided if it has been used for several consecutive weeks. Tolerance can occur in some individuals after taking the medication for several weeks or months. This means that dosages prescribed for treatment may need to be increased some over time to achieve the therapeutic response. It also means that individuals who have become addicted to estazolam will need to progressively increase the dosage to achieve the desired mood state that the addict is seeking. Addicted individuals often take several times the recommended dosage.
Withdrawal symptoms similar to those noted with sedatives/hypnotics and alcohol have occurred following the abrupt discontinuation of drugs in the benzodiazepine class. The symptoms can range from mild dysphoria (negative mood state) and insomnia to a major syndrome that may include abdominal and muscle cramps, vomiting, sweating, tremors, and convulsions.
Although withdrawal symptoms are more commonly noted after the discontinuation of higher than therapeutic doses of benzodiazepines, a proportion of patients taking benzodiazepines chronically at therapeutic doses may become physically dependent on them. Available data, however, cannot provide a reliable estimate of the incidence of dependency or the relationship of the dependency to dose and duration of treatment. Gradual withdrawal is the preferred course for any patient taking benzodiazepines for a prolonged period. Patients with a history of seizures, regardless of their concomitant antiseizure drug therapy, should not be withdrawn abruptly from benzodiazepines. Discontinuation of diazepam should be done under the supervision of a physician and often involves tapering the medication slowly and/or use of other medications to manage withdrawal symptoms.
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| OVERDOSAGE : |
Manifestations of overdoseage may include: • somnolence (extreme drowsiness or deep, prolonged sleep) • confusion • slurred speech • impaired coordination • diminished reflexes • coma • death Emergency medical treatment is advised if overdose is suspected. |
| CAUTIONS : |
| Estazolam should not be used simultaneously with alcohol or any other central nervous system depressant drugs. Taken together, these drugs can potentiate the potency and effect of each drug. Precaution should be observed in using this medication in patients who have impaired kidney, liver, or lung function. Changes in the absorption, distribution, metabolism and excretion of benzodiazepines have been reported in disease states including alcoholism, impaired liver function, in impaired kidney function. Also, in geriatric patients the half-life of elimination of the drug may be extended several hours, requiring careful monitoring and possibly a lower dosage range of prescribing medication. If estazolam is given concomitantly with other drugs acting on the central nervous system, careful consideration should be given to the pharmacology of all agents. Always check first with a physician or pharmacist before taking estazolam while taking any other prescription medications. The action of the benzodiazepines may be potentiated by anticonvulsants, antihistamines, alcohol, barbiturates, monoamine oxidase inhibitors, narcotics, phenothiazines, psychotropic medications, or other drugs that produce CNS depression. Smokers have an increased clearance of benzodiazepines as compared to nonsmokers. While no in vivo drug-drug interaction studies were conducted between estazolam and inducers of CYP3A, compounds that are potent CYP3A inducers (such as carbamazepine, phenytoin, rifampin, and barbiturates) would be expected to decrease estazolam concentrations. The metabolism of estazolam to the major circulating metabolite 4-hydroxy-estazolam and the metabolism of other triazolobenzodiazepines is catalyzed by CYP3A. Consequently, estazolam should be avoided in patients receiving ketoconazole and itraconazole, which are very potent inhibitors of CYP3A. With drugs inhibiting CYP3A to a lesser, but still significant degree, estazolam should be used only with caution and consideration of appropriate dosage reduction. The following are examples of drugs known to inhibit the metabolism of other related benzodiazepines, presumably through inhibition of CYP3A: nefazodone, fluvoxamine, cimetidine, diltiazem, isoniazide, and some macrolide antibiotics. A child born of a mother who is taking benzodiazepines maybe at some risk for withdrawal symptoms following birth. Benzodiazepines are also known to be excreted in human milk. |
| SIDE EFFECTS : |
| The most commonly observed adverse events associated with the use of estazolam were somnolence (excessive drowsiness or sleep), hypokinesia (abnormally decreased muscular movement), dizziness, and abnormal coordination. |
| FOR MORE INFORMATION : |
| *this is a condensed description of alprazolam. For more details check with your physician, pharmacist, or resources such as The Physicians' Desk Reference (PDR) or http://www.drugs.com |
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