FLURAZEPAM — flurazepam hydrochloride capsule
H.J. Harkins Company, Inc.
Flurazepam hydrochloride is chemically 7-chloro-1-[2(diethylamino)ethyl]-5-(o -fluorophenyl)-1,3-dihydro-2H -1,4-benzodiazepin-2-one dihydrochloride. It is a pale yellow, crystalline compound, freely soluble in alcohol and very soluble in water. It has a molecular weight of 460.81 and the following structural formula:
Each capsule, for oral administration, contains 15 mg or 30 mg of flurazepam hydrochloride. In addition, each capsule contains the following inactive ingredients: lactose monohydrate, magnesium stearate, pregelatinized starch , and sodium starch glycolate. Capsules shells may contain: colloidal silicon dioxide, FD&C Blue No. 1, FD&C Red No. 3, gelatin, silicon dioxide, sodium lauryl sulfate, and titanium dioxide.
Flurazepam hydrochloride is rapidly absorbed from the GI tract. Flurazepam is rapidly metabolized and is excreted primarily in the urine. Following a single oral dose, peak flurazepam plasma concentrations ranging from 0.5 to 4.0 ng/mL occur at 30 to 60 minutes post-dosing. The harmonic mean apparent half-life of flurazepam is 2.3 hours. The blood level profile of flurazepam and its major metabolites was determined in man following the oral administration of 30 mg daily for 2 weeks. The N1 -hydroxyethyl-flurazepam was measurable only during the early hours after a 30 mg dose and was not detectable after 24 hours. The major metabolite in blood was N1 -desalkyl-flurazepam which reached steady-state (plateau) levels after 7 to 10 days of dosing, at levels approximately five- to six-fold greater than the 24-hour levels observed on Day 1. The half-life of elimination of N1 -desalkyl-flurazepam ranged from 47 to 100 hours. The major urinary metabolite is conjugated N1 -hydroxyethyl-flurazepam which accounts for 22% to 55% of the dose. Less than 1% of the dose is excreted in the urine as N1 -desalkyl-flurazepam.
This pharmacokinetic profile may be responsible for the clinical observation that flurazepam is increasingly effective on the second or third night of consecutive use and that for one or two nights after the drug is discontinued both sleep latency and total wake time may still be decreased.
The single dose pharmacokinetics of flurazepam were studied in 12 healthy geriatric subjects (aged 61 to 85 years). The mean elimination half-life of desalkyl-flurazepam was longer in edlerly male subjects (160 hours) compared with younger male subjects (74 hours), while mean elimination half-life was similar in geriatric female subjects (120 hours) and younger female subjects (90 hours). After multiple dosing, mean steady-state plasma levels of desalkyl-flurazepam were higher in elderly male subjects (81 ng/mL) compared with younger male subjects (53 ng/mL), while values were similar between elderly female subjects (85 ng/mL) and younger female subjects (86 ng/ml). The mean washout half-life of desalkyl-flurazepam was longer in elderly male and female subjects (126 and 158 hours, respectively) compared with younger male and female subjects (111 and 113 hours, respectively).1
Flurazepam Hydrochloride Capsules are a hypnotic agent useful for the treatment of insomnia characterized by difficulty in falling asleep, frequent nocturnal awakenings, and/or early morning awakening. Flurazepam Hydrochloride Capsules can be used effectively in patients with recurring insomnia or poor sleeping habits, and in acute or chronic medical situations requiring restful sleep. Sleep laboratory studies have objectively determined that Flurazepam Hydrochloride Capsules are effective for at least 28 consecutive nights of drug administration. Since insomnia is often transient and intermittent short-term use is usually sufficient. Prolonged use of hypnotics is usually not indicated and should only be undertaken concomitantly with appropriate evaluation of the patient.
Flurazepam Hydrochloride Capsules are contraindicated in patients with known hypersensitivity to the drug.
Benzodiazepines may cause fetal damage when administered during pregnancy. An increased risk of congenital malformations associated with the use of diazepam and chlordiazepoxide during the first trimester of pregnancy has been suggested in several studies.
Flurazepam Hydrochloride Capsules are contraindicated in pregnant women. Symptoms of neonatal depression have been reported; a neonate whose mother received 30 mg of Flurazepam Hydrochloride Capsules nightly for insomnia during the 10 days prior to delivery appeared hypotonic and inactive during the first four days of life. Serum levels of N1 -desalkyl-flurazepam in the infant indicated transplacental circulation and implicate this long-acting metabolite in this case. If there is a likelihood of the patient becoming pregnant while receiving flurazepam, she should be warned of the potential risks to the fetus. Patients should be instructed to discontinue the drug prior to becoming pregnant. The possibility that a woman of childbearing potential may be pregnant at the time of institution of therapy should be considered.
Because sleep disturbances may be the presenting manifestation of a physical and/or psychiatric disorder, symptomatic treatment of insomnia should be initiated only after a careful evaluation of the patient. The failure of insomnia to remit after 7 to 10 days of treatment may indicate the presence of a primary psychiatric and/or medical illness that should be evaluated. Worsening of insomnia or the emergence of new thinking or behavior abnormalities may be the consequence of an unrecognized psychiatric or physical disorder. Such findings have emerged during the course of treatment with sedative-hypnotic drugs. Because some of the important adverse effects of sedative-hypnotics appear to be dose related (see PRECAUTIONS and DOSAGE AND ADMINISTRATION), it is important to use the smallest possible effective dose, especially in the elderly.
Complex behavior such as “sleep-driving” (i.e., driving while not fully awake after ingestion of a sedative-hypnotic, with amnesia for the event) have been reported. These events can occur in sedative-hypnotic-naïve as well as in sedative-hypnotic-experienced persons. Although behaviors such as sleep-driving may occur with sedative-hypnotics alone at therapeutic doses, the use of alcohol and other CNS depressants with sedative hypnotics appears to increase the risk of such behaviors, as does the use of sedative-hypnotics at doses exceeding the maximum recommended dose. Due to the risk to the patients and the community, discontinuation of sedative-hypnotics should be strongly considered for patients who report a “sleep-driving” episode.
Other complex behaviors (e.g., preparing and eating food, making phone calls, or having sex) have been reported in patients who are not fully awake after taking a sedative-hypnotic. As with sleep-driving, patients usually do not remember these events.
Rare cases of angioedema involving the tongue, glottis or larynx have been reported in patients after taking the first or subsequent doses of sedative-hypnotics, including Flurazepam Hydrochloride Capsules. Some patients have had additional symptoms such as dyspnea, throat closing, or nausea and vomiting that suggest anaphylaxis. Some patients have required medical therapy in the emergency department. If angioedema involves the tongue, glottis or larynx, airway obstruction may occur and be fatal. Patients who develop angioedema after treatment with Flurazepam Hydrochloride Capsules should not be rechallenged with the drug.
Patients receiving Flurazepam Hydrochloride Capsules should be cautioned about possible combined effects with alcohol and other CNS depressants. Also, caution patients that an additive effect may occur if alcoholic beverages are consumed during the day following the use of Flurazepam Hydrochloride Capsules for nighttime sedation. The potential for this interaction continues for several days following discontinuance of flurazepam, until serum levels of psychoactive metabolites have declined.
Patients should also be cautioned about engaging in hazardous occupations requiring complete mental alertness such as operating machinery or driving a motor vehicle after ingesting the drug, including potential impairment of the performance of such activities which may occur the day following ingestion of Flurazepam Hydrochloride Capsules.
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