PHRM 311 Lecture Notes - Lecture 12: Trihexyphenidyl, Schizophrenia, 5-Ht2C Receptor
Document Summary
Be able to recommend treatments for antipsychotic associated side effects. Involuntary contraction of muscles causing uncontrollable repetitive or twisting movements of affected body part. May involve neck, eyes, jaw, tongue, back. Benztropine 2 mg po/im/iv stat, then 1-2 mg bid x 2 days. Can occur within hours of starting antipsychotics (minutes if given iv or im) Response to iv in 5 mins. Response to im in 20 mins. Resembles parkinson"s disease, with symptoms that include tremors, rigidity, mask-like face, slow thinking, and salivation. Benztropine 1 mg bid (range: 2-6 mg/day) Trihexyphenidyl 2 mg bid (range: 4- 12 mg/day) Can occur days to weeks after an antipsychotic is started or after dose increase. Use of anticholinergic should be reviewed at least every 3 months. Do not prescribe at night since symptoms are absent during sleep. Can be mistaken for depression or negative symptoms. More common in elder females and those with pre-existing neurological damage (e. g. head injury, stroke)
