Restoril
Restoril
Generic Name
Restoril
Brand Names
for temazepam, a short‑to‑intermediate–acting benzodiazepine widely prescribed for the short‑term treatment of insomnia. Its pharmacologic profile, dosing conventions, and safety considerations are summarized below for rapid reference by medical students and clinicians.
Mechanism
- Positive allosteric modulator of the GABAA receptor – enhances chloride ion influx, hyperpolarizing neurons and producing:
- Sedation and hypnotic effects
- Anxiolysis
- Muscle relaxation
- Amnesic properties (short‑term memory impairment)
- Selective affinity for β2 and β3 subunits of GABAA receptors contributes to its hypnotic potency with relatively lower anxiolytic and muscle‑relaxant activity compared with diazepam.
Pharmacokinetics
| Parameter | Typical value range |
| Absorption | Rapid, peak plasma concentration (tmax) 1–2 h after oral dosing. |
| Distribution | Highly lipophilic; volume of distribution 4–5 L/kg. ~50 % bound to plasma proteins; ~40 % crosses blood–brain barrier. |
| Metabolism | Predominantly hepatic via CYP‑3A4 and CYP‑2C19 to *α‑hydroxy‑temazepam* (inactive). No active metabolites. |
| Elimination | Renally excreted (~35 % unchanged, rest as metabolites). Mean half‑life 8–12 h; prolonged to 12–14 h in elderly. |
| Food effect | Co‑administration with food does not clinically alter bioavailability. |
Indications
- Short‑term (<2–4 weeks) treatment of insomnia characterized by:
- Difficulty initiating or maintaining sleep
- Non‑compliance with other hypnotics or sleep hygiene strategies
- Off‑label use: acute anxiety, procedural sedation (rare), pre‑operative anxiolysis, and alcohol withdrawal in short bursts.
Contraindications
- Absolute contraindications:
- History of benzodiazepine abuse, hypersensitivity to temazepam or other benzodiazepines
- Severe respiratory insufficiency, COPD, obstructive sleep apnea (OSA) without continuous positive airway pressure (CPAP) therapy
- Severe hepatic or renal impairment
- Pregnant or lactating females unless benefit outweighs risk
- Warnings:
- Cognitive and psychomotor impairment – caution vehicles, fall risk
- Respiratory depression – careful monitoring in combination with opioids or other CNS depressants
- Tolerance, dependence, withdrawal – discontinue gradually
- Use in adolescents – risk of extrapyramidal reactions; limited evidence
- Concurrent alcohol use – risk of additive CNS depression
Dosing
| Population | Starting dose | Titration | Max daily dose | Administration notes | |
| Adults | 5 mg PO <2 h before bedtime | Increase by 2.5 mg increments every 3–5 days, as tolerated | 15 mg/day (max) | Take with plain water; avoid caffeine/alcohol | |
| Elderly, hepatic/renal decline | 2.5 mg PO | Titrate cautiously | 5–10 mg/day | Monitor for oversedation | |
| Children <18 y | Not approved; use with extreme caution | 1–2 mg PO | 5 mg/day | Not recommended | |
| Rapid‑release capsule | 5 mg | - | - | If insomnia is very severe, short‑acting formulation may be used |
• Dosing interval: Once nightly. Do not take more than daily max. Avoid bedtime dosing that would lead to next‑day sedation.
Adverse Effects
- Common (≥10 %):
- Somnolence, dizziness, coordination problems
- Day‑time fatigue, impaired concentration
- Dry mouth, blurred vision
- Mild gastrointestinal upset
- Serious (≤1 %):
- Respiratory depression (especially with opioids or sedatives)
- Severe extrapyramidal reactions
- Severe hypotension or hypotension‑associated syncope
- Severe hepatic injury (rare, idiosyncratic)
- Rebound insomnia and withdrawal: abrupt cessation may precipitate rebound insomnia, anxiety, tremor, agitation.
Monitoring
| Parameter | Frequency | Rationale |
| Clinical response | Every 1–2 weeks in early use | Assess efficacy, tolerance |
| Cognitive/psychomotor function | At each visit | Detect impairment |
| Liver function tests | Every 4–6 weeks if >6 mo therapy | Detect hepatotoxicity |
| Renal function | Every 3–6 months | Dose adjustments needed |
| Sleep Diary | Daily | Objective measure of improvement |
| Blood–pressure & pulse | At each visit | Monitor for hypotension |
Clinical Pearls
- Use as a “last‑resort” hypnotic – because of rapid tolerance, limit therapy to ≤4 weeks; otherwise switch to non‑benzodiazepine hypnotics (e.g., zolpidem) or behavioral interventions.
- Withdrawal protocols: Reduce dose by 20 % every 4–7 days; a slow taper mitigates rebound insomnia and anxiety.
- Drug‑drug interaction caution – potent CYP3A4 inhibitors (ketoconazole, ritonavir) markedly increase temazepam levels; induceducers (rifampin, carbamazepine) reduce efficacy.
- Avoid in OSA unless CPAP is used – temazepam dampens upper‑airway muscle tone, exacerbating airway collapse.
- Cognitive side‑effects correlate with the dose – keep below 10 mg/day in frail adults; consider cognitive screening (Montreal Cognitive Assessment) if sedation interferes with daily tasks.
- Rebound insomnia is dose‑dependent – higher maintenance doses (>10 mg) are more likely to create rebound phenomena.
- Use of the “flip‑flop” formulation – in patients with severe hepatic impairment, a delayed‑release formulation can reduce peak plasma concentrations, decreasing CNS depression.
--
• *This drug card is intended as a quick‑reference guide. Verify patient‑specific factors and institutional protocols before prescribing.*