Can clonazepam (Klonopin) use at a dose of 0.25 milligrams (mg) once daily cause short-term memory impairment?

Clonazepam and Short-Term Memory Impairment

Yes, clonazepam at a dose of 0.25 mg once daily can cause short-term memory impairment, particularly affecting the formation of long-term memories from short-term memory (anterograde amnesia). 1, 2

Mechanism of Memory Impairment

• Benzodiazepines like clonazepam affect memory by impairing the transfer of information from short-term to long-term memory storage, resulting in anterograde amnesia (inability to form new memories) 1
• Even at low doses (0.25 mg), clonazepam has been shown to impair memory encoding, particularly affecting free recall of information 2
• Memory impairment occurs because events are not properly consolidated into memory storage, though information stored prior to taking clonazepam is typically not affected 1

Evidence from Clinical Research

• A 2024 study demonstrated that even a single low dose of clonazepam (0.25 mg) impaired memory encoding in the free recall task, though some aspects of recognition memory remained intact 2
• Memory impairment is more pronounced with benzodiazepines that have high receptor affinity, accumulate in the body, or are eliminated slowly 1
• Clonazepam has a long elimination half-life of 30-40 hours, which contributes to its potential for causing cognitive side effects 3

FDA-Recognized Side Effects

• The FDA label for clonazepam specifically lists memory impairment among the acute withdrawal signs and symptoms, indicating its effect on cognitive function 4
• Common side effects include drowsiness, ataxia, and behavior changes that can affect cognitive function 5
• The FDA notes that while tolerance may develop to the therapeutic effects of clonazepam, "little tolerance develops to the amnestic reactions and other cognitive impairments" caused by benzodiazepines 4

Risk Factors and Clinical Considerations

• Memory impairment risk increases with:

  • Higher doses 1
  • Longer duration of use 4
  • Advanced age 1
  • Concomitant use with other CNS depressants 4

• Patients taking clonazepam are often unaware of their memory impairment unless it is specifically pointed out to them 1

• The American Geriatrics Society Beers Criteria lists clonazepam as potentially inappropriate in older adults partly due to its cognitive effects 3

Alternative Treatments with Lower Cognitive Impact

• For conditions like REM sleep behavior disorder where clonazepam is commonly used, melatonin (3-12 mg at bedtime) may be a better option with fewer cognitive side effects 3
• The American Academy of Sleep Medicine recommends considering melatonin as an alternative to clonazepam due to its more favorable side effect profile 3

Important Clinical Caveat

• When prescribing clonazepam, patients should be fully informed about potential memory impairment effects 1
• Regular assessment of cognitive function is important in patients on long-term clonazepam therapy 6
• Memory impairment may persist beyond the period of acute withdrawal, as part of a protracted withdrawal syndrome 4