Medication-induced dyskinesias Acute
dystonia is a sustained muscle contraction that sometimes appears soon after administration of
antipsychotic medications. Any muscle in the body may be affected, including the jaw, tongue, throat, arms, or legs. When the throat muscles are involved, this type of dystonia is called an acute
laryngospasm and is a medical emergency because it can impair breathing. Long-term use of amphetamines may increase the risk of
Parkinson's disease (PD): in one
retrospective study with over 40,000 participants it was concluded that amphetamine abusers generally had a 200% higher chance of developing PD versus those with no history of abuse; the risk was much higher in women, almost 400%. There remains some controversy as of 2017.
Levodopa-induced dyskinesia (LID) is evident in patients with Parkinson's disease who have been on
levodopa () for prolonged periods of time. LID commonly first appears in the foot, on the most affected side of the body. There are three main types that can be classified on the basis of their course and clinical presentation following an oral dose of : •
Off-period dystonia – correlated to the
akinesia that occurs before the full effect of sets in, when the plasma levels of are low. In general, it occurs as painful spasms in the foot. Patients respond to therapy. •
Diphasic dyskinesia – occurs when
plasma levels are rising or falling. This form occurs primarily in the lower limbs (though they can happen elsewhere) and is usually
dystonic (characterized by apparent rigidity within muscles or groups thereof) or
ballistic (characterized by involuntary movement of muscles) and will not respond to dosage reductions. •
Peak-dose dyskinesia – the most common form of levodopa-induced dyskinesia; it correlates with the plateau plasma level. This type usually involves the upper limbs more (but could also affect the head, trunk and respiratory muscles), is choreic (of chorea), and less disabling. Patients will respond to reduction but may be accompanied by deterioration of
parkinsonism. Peak-dose -induced dyskinesia has been suggested to be associated with cortical dysregulation of dopamine signaling.
Chronic or tardive Late-onset dyskinesia, also known as
tardive dyskinesia, occurs after long-term treatment with an
antipsychotic drug such as
haloperidol (Haldol) or
amoxapine (Asendin). The symptoms include tremors and writhing movements of the body and limbs, and abnormal movements in the face, mouth, and tongue including involuntary lip smacking, repetitive pouting of the lips, and tongue protrusions.
Rabbit syndrome is another type of chronic dyskinesia, while
orofacial dyskinesia may be related to persistent replication of
herpes simplex virus type 1.
Non-motor Two other types,
primary ciliary dyskinesia and
biliary dyskinesia, are caused by specific kinds of ineffective movement of the body, and are not
movement disorders. ==Treatment==