Myoclonus & seizures


Muscle jerks in several muscle groups/limbs.
May be a sign of opioid neurotoxicity.

If combined with other symptoms of opioid neurotoxicity (sedation, confusion, hallucinations, agitation) rotate opioid. See Manage pain Opioid Calculations
If patient in last hours to days of life manage myoclonus with midazolam 1-5mg sc q1hr prn or lorazepam 0.5-2mg q6-8hrs prn


Immediate therapy:

  • midazolam 5-10mg sc/iv/im q10 minutes until stopped
  • lorazepam 1-2mg sc/iv/im q10 min until stopped

Status epilepticus: if seizure persists after 3 doses of above add Phenobarbital 100mg sc. May need midazolam or lorazepam infusion if persists. Consider propofol for intractable seizures. Consult PC.

Prevention of further seizures:   Levitiracetam (Keppra) p.o. or s.c.. Check eGFR prior to starting as max dose dependent on renal function. Start 500mg p.o. bid (frail older adults, severe CKF may use 500mg once daily) Titrate slowly. In adults maximum 2g daily if eGFR 50-80. Maximum 1.5g daily if eGFR 30-50. Maximum 1g daily if eGFR less than 30. May be used s.c. at doses equivalent to oral.