Can tizanidine be added to a patient taking Restoril (temazepam)?

Can Tizanidine Be Added to Restoril (Temazepam)?

Exercise extreme caution when combining tizanidine with temazepam (Restoril), as both are CNS depressants that produce additive sedation, and this combination significantly increases the risk of respiratory depression, excessive sedation, hypotension, bradycardia, and falls—particularly in elderly patients.

Key Safety Concerns

The FDA drug label for tizanidine explicitly warns that "the sedation may be additive when tizanidine is taken in conjunction with drugs (baclofen, benzodiazepines) or substances (e.g., alcohol) that act as CNS depressants" 1. Similarly, the Restoril label states that "consideration should be given to potential additive effects" when combining with other CNS depressants 2.

Primary Risks of This Combination:

• Enhanced CNS depression: Both medications cause dose-dependent sedation, drowsiness, dizziness, and ataxia 3
• Respiratory depression: Benzodiazepines like temazepam can cause respiratory depression, which is potentiated by concurrent CNS depressants 4
• Cardiovascular effects: Tizanidine causes hypotension and bradycardia, which may be exacerbated when combined with sedatives 1, 5, 6
• Fall risk: The Restoril label specifically warns that "increased drowsiness and decreased consciousness may increase the risk of falls" 2

Clinical Decision Algorithm

If combination is deemed necessary:

1. Start with lowest possible doses:

   • Temazepam: 7.5 mg (especially in elderly/debilitated patients) 2
   • Tizanidine: Start at 2 mg and titrate slowly 1

2. Monitor closely for:

   • Excessive sedation or somnolence
   • Orthostatic hypotension (blood pressure drops)
   • Bradycardia (heart rate <60 bpm)
   • Respiratory depression
   • Confusion, ataxia, or falls

3. High-risk populations requiring extra caution:

   • Elderly patients: Both medications require dose reduction; elderly are at substantially higher risk for oversedation, confusion, ataxia, and falls 2, 1
   • Hepatic or renal impairment: Tizanidine clearance is reduced >50% in renal insufficiency 1
   • Patients on other CNS depressants or opioids: Risk of fatal respiratory depression 2

4. Timing considerations:

   • Avoid taking both medications simultaneously
   • Consider separating administration times if possible
   • Temazepam is typically dosed at bedtime for insomnia 7, 8

Important Caveats

Benzodiazepines are generally not recommended for chronic use. The 2017 AASM guideline suggests temazepam only as a weak recommendation for sleep-onset and maintenance insomnia 8. The 2008 insomnia guideline notes that benzodiazepines are associated with risks for abuse, addiction, and tolerance 7.

Consider alternatives: If the patient needs both muscle relaxation and sleep aid, discuss with the prescriber whether:

• Non-pharmacologic approaches for insomnia (cognitive behavioral therapy) could reduce benzodiazepine need
• Alternative sleep medications with less CNS depression might be safer
• The tizanidine indication is strong enough to justify the added risk

Drug interaction monitoring: If the patient is also taking CYP1A2 inhibitors (ciprofloxacin, fluvoxamine, oral contraceptives), tizanidine levels will be significantly elevated, dramatically increasing toxicity risk 1, 9, 10. This combination with benzodiazepines would be particularly dangerous.

Bottom Line

While not absolutely contraindicated, this combination should only be used when benefits clearly outweigh risks, with careful dose titration, close monitoring, and patient education about fall risk and avoiding activities requiring alertness. Document the rationale for combination therapy and ensure the patient understands warning signs of excessive sedation or cardiovascular depression requiring immediate medical attention.