Akathisia - Causes

Causes

Akathisia is most often seen as a side effect of antipsychotic medications, but has other causes as well:

• Antipsychotics such as haloperidol (Haldol), droperidol, pimozide, trifluoperazine, amisulpride, risperidone, aripiprazole (Abilify), ziprasidone and asenapine (Saphris). Less common in sedating antipsychotics such as zuclopenthixol (Cisordinol) or chlorpromazine where anticholinergic and antihistaminergic effects counteract akathisia to a degree.
• SSRIs, such as fluoxetine (Prozac). It has also been documented with the use of paroxetine (Paxil). Akathisia has been studied as the mechanism by which SSRI-induced suicidality occurs.
• Other antidepressants, such as venlafaxine (Effexor), the tricyclics and trazodone (Desyrel).
• Certain anti-emetic drugs, particularly the dopamine blockers, such as metoclopramide (Reglan), prochlorperazine (Compazine), and promethazine.
• Antihistamines, such as cyproheptadine or diphenhydramine.
• Opioid withdrawal.
• Barbiturates withdrawal.
• Cocaine withdrawal (Mostly in heavy and long-term users).
• Amphetamines and any stimulant (including coffee, tea, tobacco, etc.).
• Benzodiazepine, and alcohol withdrawal.
• GHB- gamma hydroxy butyric acid.
• Chondromalacia patellae, resulting in discomfort when knees are bent.
• Serotonin syndrome.

The 2006 UK study by Healy, Herxheimer, and Menkes observed that akathisia is often miscoded in antidepressant clinical trials as "agitation, emotional lability, and hyperkinesis (overactivity)". The study further points out that misdiagnosis of akathisia as simple motor restlessness occurs, but that this is more properly classed as dyskinesia. Healy, et al., further show links between antidepressant-induced akathisia and violence, including suicide, as akathisia can "exacerbate psychopathology." The study goes on to state that there is extensive clinical evidence correlating akathisia with SSRI use, showing that approximately ten times as many patients on SSRIs as those on placebos showed symptoms severe enough to drop out of a trial (5.0% compared to 0.5%).