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Action/Kinetics:
Combines with benzodiazepine receptors, which are part of the benzodiazepine-GABA receptor-chloride ionophore complex. Results in enhanced inhibitory action of GABA leading to interference of transmission of nerve impulses in the reticular activating system.
Onset: 17 min. The major active metabolite,
N-desalkyl-flurazepam, is active and has a
t
1/2 of 47-100 hr.
Time to peak plasma levels, flurazepam: 0.5-1 hr;
active metabolite: 1-3 hr.
Duration: 7-8 hr.
Maximum effectiveness: 2-3 days (due to slow accumulation of active metabolite). Significantly bound to plasma protein. Elimination is slow because metabolites remain in the blood for several days. Exceeding the recommended dose may result in development of tolerance and dependence.
Uses:
Insomnia (all types). Is increasingly effective on the second or third night of consecutive use and for one or two nights after the drug is discontinued.
Contraindications:
Hypersensitivity. Pregnancy or in women wishing to become pregnant. Depression, renal or hepatic disease, chronic pulmonary insufficiency, children under 15 years.
Special Concerns:
Use during the last few weeks of pregnancy may result in CNS depression of the neonate. Use during lactation may cause sedation and feeding problems in the infant. Geriatric clients may be more sensitive to the effects of flurazepam.
Side Effects:
CNS: Ataxia, dizziness, drowsiness/sedation, headache, disorientation. Symptoms of stimulation including nervousness, apprehension, irritability, and talkativeness.
GI: N&V;, diarrhea, gastric upset or pain, heartburn, constipation.
Miscellaneous: Arthralgia, chest pains, or palpitations. Rarely, symptoms of allergy, SOB, jaundice, anorexia, blurred vision.
Laboratory Test Alterations:
Alkaline phosphatase, bilirubin, serum transaminases.
Drug Interactions:
-
Cimetidine /
Flurazepam effect R/T
liver breakdown
-
CNS depressants / Addition or potentiation of depression --drowsiness, lethargy, stupor, respiratory depression or collapse, coma, and possible death
-
Disulfiram /
Flurazepam effect R/T
liver breakdown
-
Ethanol / Additive depressant effects up to the day following flurazepam administration
-
Isoniazid /
Flurazepam effect R/T
liver breakdown
-
Oral contraceptives / Either
or
effect of benzodiazepines R/T effect on liver breakdown
-
Rifampin /
Effect of benzodiazepines R/T
liver breakdown
How Supplied:
Capsule: 15 mg, 30 mg
Dosage
?Capsules
Adults: 15-30 mg at bedtime; 15 mg for geriatric and/or debilitated clients.
