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temazepam (Restoril)
Tradename: Restoril. DEA-controlled substance: class 4.
Indications: short-term management of transient insomnia
Contraindications:
1) depression
2) narrow-angle glaucoma
3) pregnancy
Dosage: 15-30 mg PO QHS [1,2].
Tabs: 7.5, 15 & 30 mg.
Pharmacokinetics:
1) protein binding is 96%
2) time to peak effect within 2-3 hours
3) extensively metabolized in the liver primarily by conjugation
4) metabolites are pharmacologically inactive [2]
5) excreted mainly in the urine as inactive metabolites
6) elimination 1/2life is 9-12 hours
Adverse effects:
1) common (> 10%)
- drowsiness, fatigue, impaired coordination, lightheadedness, memory impairment, insomnia, dysarthria, anxiety, decreased libido, depression, headache, dry mouth, constipation, diarrhea, decreased salivation, nausea/vomiting, tachycardia, chest pain, blurred vision, sweating, rash, increased or decreased appetite
2) less common (1-10%)
- confusion, nervousness, syncope, dizziness, akathisia, increased salivation, hypotension, rigidity, tremor, dermatitis, nasal congestion, weight gain or weight loss, hyperventilation, tinnitus, muscle cramps
3) uncommon (< 1%)
- menstrual irregularities, blood dyscrasias, reflex slowing, drug dependence
Drug interactions:
1) disulfiram, nefazodone, fluoxetine, flovoxamine, cimetidine, ranitidine, erythromycin, grapefruit juice decrease metabolism of benzodiazepines
2) CNS depressants, EtOH: in combination increase CNS depression
3) antiepileptic agents, rifampin: increase metabolism of benzodiazepines
4) flumazenil (Romazicon): is a benzodiazepine antagonist
5) probenecid may inhibit glucuronide conjugation
Laboratory:
1) specimen: serum, plasma (EDTA)
2) methods: GLC, HPLC
Mechanism of action:
1) produces CNS depression at the subcortical level & at higher doses, the cortical level as well
2) potentiates inhibitory effects of GABA by increasing neuronal membrane permeability to chloride
Interactions
drug interactions
drug adverse effects (more general classes)
General
benzodiazepine
Properties
MISC-INFO: elimination route KIDNEY
1/2life 8-25 HOURS
13 +/- 3 HOURS
protein-binding 98%
elimination by hemodialysis -
pregnancy-category X
safety in lactation -
Database Correlations
PUBCHEM cid=5391
References
- The Pharmacological Basis of Therapeutics, 9th ed.
Gilman et al, eds. Permagon Press/McGraw Hill, 1996
- Manual of Medical Therapeutics, 28th ed, Ewald &
McKenzie (eds), Little, Brown & Co, Boston, 1995, pg 7
- Drug Information & Medication Formulary, Veterans Affairs,
Central California Health Care System, 1st ed., Ravnan et al
eds, 1998
- Kaiser Permanente Northern California Regional Drug
Formulary, 1998
- Clinical Guide to Laboratory Tests, NW Tietz (ed) 3rd ed,
WB Saunders, Philadelpha 1995