Drug Induced Movement Disorders

Akathisia (inability to sit still) is a term introduced to describe restlessness. It is now used to describe the restlessness observed in patients secondary to neuroleptics, typically manifested by excessive voluntary movement.  The movements are typically stereotypical motor patterns such as pacing, body rocking, or foot tapping.  Occasionally Akathisia can result in repetitive vocalizations.  Some authors now describe these movements as "stereotypies" associated with an abnormal subjective sensation.

Occasionally the inner subjective feeling of restlessness is absent.  The term "pseudoakathisia" has been used in this situation.

Akathisia is likely the most common neuroleptic induced movement disorder.  The symptoms typically start within days of neuroleptic exposure but may be delayed as long as several weeks.  Up to 90 percent patients exposed neuroleptics will experience some degree of akathisia within the first three to four months. There's no age or sex predisposition.

Akathisia may slowly subsided with continued therapy but often persists, resulting in poor medication compliance.  This condition is often misdiagnosed as increased agitation resulted in higher doses of neuroleptics further aggravating the situation.

Treatment

  The key is prevention and failing that early recognition.

Decreasing the dose of the offending medication would be the treatment of choice.  When this is not possible switching to the neuroleptic of a lower potency would be favored.  If this fails treatment with other medications including anticholinergics, amantadine, and beta-blockers (e.g. propranolol) has been useful. The most effective treatments appear to be lipophilic beta-blockers, especially propranolol and metoprolol, Anticholinergic agent use, commonly given to prevent acute dystonias especially in high-risk patients, is controversial as some feel long-term prophylaxis increases the risk of tardive movement disorders. Propranolol should be the drug of first choice. The dose required is usually low.  Treatment should result in improvement within three to five days. Other drugs occasionally reported to be effective include clonidine, clonazepam, amitriptyline, and opiods. 

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