Clinical Monograph: Temazepam 30 mg

1. Classification and Chemical Overview

Temazepam is a 3-hydroxy derivative of the 1,4-benzodiazepine class. Chemically designated as 7-chloro-1,3-dihydro-1-methyl-5-phenyl-3-hydro-1,4-benzodiazepin-2-one. Under the Anatomical Therapeutic Chemical (ATC) system, temazepam is indexed under N05BA07.

• Product Context: The 30 mg strength represents a high therapeutic unit dose of temazepam formulated for immediate release. Because of its potent hypnotic properties, it is typically prescribed for short-term use when insomnia is severe and debilitating.

• Controlled Status: Classified as a Controlled Substance (Schedule IV under the US CSA; Schedule 4 / Prescription Only Medicine internationally) due to its high potential for physical dependence, misuse liability, and central nervous system depression risks.

2. Mechanism of Action and Pharmacodynamics

Temazepam acts as a positive allosteric modulator at central nervous system FRENTEA​ receptor complexes:

• Receptor Binding: Binds selectively to benzodiazepine binding sites on postsynaptic FRENTEA​ receptors throughout the cerebral cortex and limbic system.

• Chloride Conductance Enhancement: Facilitates GABA-mediated opening of chloride ion channels, generating hyperpolarization of neuronal membranes and suppressing electrical excitability.

• Hypnotic Profile: Shortens sleep latency, reduces nighttime awakenings, and increases total sleep duration without markedly altering REM sleep stages compared to older sedatives like barbiturates.

3. Approved Clinical Indications and Dosing Scope

Licensing for temazepam includes:

• Insomnia: Short-term management of transient and short-term insomnia characterized by difficulty falling asleep or frequent nocturnal awakenings.

Dosing & Administration Regimen:

• Adult Dosage: Standard therapeutic doses typically range from 10 mg to 20 mg taken orally shortly before retiring. The 30 mg strength is a high unit dose reserved for severe treatment-resistant insomnia or patients with demonstrated benzodiazepine tolerance.

• Duration Restrictions: Treatment duration must be kept strictly short-term (typically ranging from 7 to 14 days, not exceeding 4 weeks including a gradual taper period) to minimize the development of tolerance, psychological dependence, and rebound insomnia.

4. Pharmacokinetic Profile and Metabolic Fate

• Absorption: Rapidly and completely absorbed following oral ingestion, with peak plasma concentrations (Cmax​) attained within 30 minutes to 1.5 hours post-dose.

• Distribution: Moderate lipophilicity with plasma protein binding of approximately 96%. Crosses the blood-brain barrier and placenta rapidly.

• Biotransformation: Conjugated directly in the liver primarily via glucuronidation into inactive metabolites (such as temazepam glucuronide), bypassing extensive oxidative metabolism by cytochrome P450 enzymes. A minor fraction is converted into oxazepam.

• Elimination: Excreted predominantly through the kidneys in urine as conjugated metabolites. The elimination half-life (t1/2​) averages 8 to 15 hours, making it an intermediate-acting agent suited for sleep induction with minimal daytime hangover compared to long-acting benzodiazepines.

5. Physiological Effects and Adverse Event Spectrum

Temazepam suppresses central nervous system arousal, sleep cycle disruption triggers, motor coordination, and cognitive consolidation.

Adverse Drug Reaction Spectrum

• Very Common ($\ge 1/10$): Residual sedation (“hangover” effect), somnolence, fatigue, headache, dizziness.

• Common ($\ge 1/100$ to $<1/10$): Lethargy, blurred vision, ataxia, confusion, dry mouth, gastrointestinal upset, muscle weakness.

• Uncommon ($\ge 1/1,000$ to $<1/100$): Paradoxical reactions (aggressiveness, excitation, hallucinations, rage), anterograde amnesia, skin rashes, changes in libido.

• Rare / Severe (<1/1,000): Severe respiratory depression, anaphylaxis, blood dyscrasias, severe withdrawal symptoms/seizures upon abrupt cessation.

6. Contraindications, Drug Interactions, and Clinical Precautions

Contraindicaciones

• Known hypersensitivity to temazepam or other benzodiazepines.

• Severe acute respiratory insufficiency, sleep apnea syndrome, or myasthenia gravis.

• Severe hepatic impairment.

• Acute narrow-angle glaucoma.

Key Drug Interactions

• Opioids & CNS Depressants: Co-administration with opioids, alcohol, barbiturates, or sedatives produces profound, synergistic central nervous system and respiratory depression, significantly elevating the risk of coma and fatal overdose.

• Alcohol: Potentiates hypnotic and sedative effects, impairing next-day psychomotor performance and elevating overdose risks.

Clinical Precautions and Monitoring

• Boxed Warning (Concomitant Opioid Use & Abuse/Dependence): Combined use of benzodiazepines and opioids increases the risk of profound sedation, respiratory depression, coma, and death. Temazepam carries a risk of physical dependence and psychological addiction; abrupt discontinuation after regular use precipitates a withdrawal syndrome characterized by severe anxiety, tremor, insomnia, and grand mal seizures.

• Next-Day Impairment: Warn patients about potential residual daytime sedation, impaired cognitive alertness, and reduced motor coordination affecting driving or machinery operation.