Medication-Induced Movement Disorders and Other Adverse Effects of Medication

What is the purpose of the medication induced movement disorders chapter

Describe important medication adverse effects that can affect treatment or be mistaken for mental disorders

Are the conditions in this chapter mental disorders

No

What medication group causes many movement disorders in this chapter

Antipsychotics and other dopamine receptor blocking agents

What nonpsychiatric medications can also block dopamine receptors and cause movement disorders

Some anti nausea and gastrointestinal motility medications

What is medication induced parkinsonism

Parkinson like motor symptoms that develop after exposure to a medication capable of causing parkinsonism

What medication group most commonly causes medication induced parkinsonism

Antipsychotic medications that block dopamine D2 receptors

What are the main motor features of medication induced parkinsonism

Rigidity / bradykinesia / tremor / gait and posture changes

What is bradykinesia

Abnormally slowed movement and difficulty initiating or completing movement

What is akinesia

Marked reduction or absence of spontaneous movement

What is parkinsonian rigidity

Involuntary stiffness with increased resistance to passive movement

What is lead pipe rigidity

Constant resistance throughout passive range of motion

What is cogwheel rigidity

Ratchet like resistance caused by tremor superimposed on rigidity

What is a pill rolling tremor

A slow rhythmic resting tremor associated with parkinsonism

What gait changes can occur with medication induced parkinsonism

Short shuffling steps / reduced arm swing / stooped posture

What facial change can occur with medication induced parkinsonism

Reduced facial expression and blinking

What other functional problems can occur with medication induced parkinsonism

Difficulty grooming / swallowing / writing / walking / maintaining balance

When does antipsychotic induced parkinsonism commonly develop

About 2 to 4 weeks after starting or increasing medication and usually within 3 months

What medication history clue supports medication induced parkinsonism

New parkinsonism begins after starting or increasing a medication capable of causing it

What pattern strongly suggests medication induced parkinsonism rather than Parkinson disease

Relatively rapid bilateral onset after medication exposure

Is medication induced parkinsonism always symmetric

No

How does Parkinson disease commonly begin compared with medication induced parkinsonism

Parkinson disease often begins unilaterally and progresses asymmetrically

What symptoms support Parkinson disease rather than medication induced parkinsonism

REM sleep behavior disorder / loss of smell / autonomic symptoms / characteristic progressive neurological findings

Why can medication induced parkinsonism be mistaken for depression

Bradykinesia and reduced activity may resemble psychomotor retardation and low motivation

Why can medication induced parkinsonism be mistaken for schizophrenia negative symptoms

Reduced movement / facial expression / spontaneity may resemble negative symptoms

What is neuroleptic malignant syndrome or NMS

A potentially life threatening reaction associated with antipsychotics or other dopamine receptor blocking agents

What are the major features of NMS

Hyperthermia / severe generalized rigidity / altered mental status / autonomic instability

What temperature finding supports NMS

Fever above 38 degrees Celsius or 100.4 degrees Fahrenheit on repeated measurement

What type of rigidity is characteristic of severe NMS

Generalized lead pipe rigidity

What mental status changes can occur in NMS

Delirium / altered consciousness / stupor / coma

What autonomic symptoms can occur in NMS

Tachycardia / sweating / blood pressure instability / rapid breathing / urinary incontinence

What laboratory finding commonly occurs in NMS

Marked elevation of creatine kinase

Why does creatine kinase rise in NMS

Muscle injury and rhabdomyolysis from severe rigidity

When does NMS usually occur relative to dopamine blocking medication exposure

Usually within days and most often early after medication initiation or change

Can NMS occur at normal therapeutic antipsychotic doses

Yes

What factors may increase NMS risk

High potency dopamine blocking medications / rapid titration / high doses / dehydration / agitation / exhaustion

Why is NMS an emergency

It can cause severe systemic complications and death

What disorders can resemble NMS

Serotonin syndrome / malignant catatonia / heat stroke / infections / alcohol or sedative withdrawal / stimulant toxicity

How does NMS differ from ordinary medication induced parkinsonism

NMS includes fever / severe systemic illness / altered mental status / autonomic instability

What is medication induced acute dystonia

Sudden sustained involuntary muscle contractions or abnormal postures caused by medication

What medications most commonly cause acute dystonia

Antipsychotics and other dopamine receptor blocking medications

When does acute dystonia usually appear

Within hours to several days after starting or rapidly increasing the causative medication

About how many acute dystonia cases appear within 5 days

Approximately 90 percent

What body areas are commonly affected by acute dystonia

Head / neck / jaw / tongue / eyes / trunk

What is an oculogyric crisis

Sustained involuntary deviation of the eyes

What is torticollis

Abnormal twisting or positioning of the neck

What is trismus

Severe jaw muscle contraction producing lockjaw

What is opisthotonos

Severe backward arching of the head neck and spine

What is acute laryngeal dystonia

Dystonia involving the larynx that can obstruct the airway

Why is laryngeal dystonia especially dangerous

It can cause respiratory obstruction and become life threatening

What symptoms may suggest laryngeal dystonia

Stridor / difficulty speaking / swallowing difficulty / shortness of breath / throat tightening

Who is at higher risk for acute dystonia

Children / younger adults / males / people with previous dystonic reactions

How does acute dystonia differ from tardive dystonia

Acute dystonia develops shortly after medication changes / tardive dystonia emerges after longer exposure and may persist

How does acute dystonia differ from NMS

NMS includes generalized rigidity plus fever and systemic instability

What is medication induced acute akathisia

Subjective inner restlessness accompanied by observable inability to remain still

What movements commonly occur with akathisia

Fidgeting / leg swinging / rocking / pacing / shifting from foot to foot

What subjective feeling is central to akathisia

Compelling inner restlessness and need to move

Where is akathisia often felt most strongly

In the legs

When does acute akathisia usually appear

Within about 4 weeks of starting or increasing a causative medication

What medications can cause akathisia

Antipsychotics / SSRIs / tricyclic antidepressants / dopamine related medications / some calcium channel blockers

Why is akathisia important in psychiatric practice

It can be mistaken for anxiety agitation mania or worsening psychosis

What emotional symptoms may accompany akathisia

Anxiety / dysphoria / irritability / aggression

What serious behavioral risk has been associated with akathisia

Suicide attempts

What medication dose relationship can help identify akathisia

Increasing the causative medication often worsens the restlessness

How can akathisia differ from ordinary anxiety

Akathisia includes a strong physical compulsion to move and often begins after a medication change

How can akathisia differ from mania

Mania includes a broader episodic syndrome such as elevated or irritable mood and other manic symptoms

What is tardive dyskinesia

Delayed onset involuntary abnormal movements associated with long term dopamine receptor blocking medication exposure

How long must tardive dyskinesia movements persist

At least 4 weeks

What body areas are commonly involved in tardive dyskinesia

Tongue / jaw / face / trunk / limbs

What kinds of movements occur in tardive dyskinesia

Choreiform / athetoid / stereotyped or semirhythmic involuntary movements

What are choreiform movements

Rapid jerky irregular nonrepetitive movements

What are athetoid movements

Slow writhing continuous movements

What common facial and mouth movements can occur in tardive dyskinesia

Lip smacking / chewing movements / tongue movements / facial grimacing

When does tardive dyskinesia usually begin

Insidiously after prolonged medication exposure

Can tardive dyskinesia persist after the causative medication is stopped

Yes

What are major risk factors for tardive dyskinesia

Older age / greater cumulative antipsychotic exposure / previous extrapyramidal symptoms

Do second generation antipsychotics eliminate tardive dyskinesia risk

No / risk is lower overall but still present

Why is distinguishing tardive dyskinesia from medication induced parkinsonism important

Treatments for one condition may worsen the other

What may anticholinergic treatment for parkinsonism do to tardive dyskinesia

It may worsen tardive dyskinesia

What may VMAT2 inhibitor treatment for tardive dyskinesia do to parkinsonism

It may worsen parkinsonian symptoms

How does tardive dyskinesia differ from acute dystonia or akathisia

Tardive dyskinesia develops later and can persist for months or years

What is tardive dystonia

A delayed dystonic movement syndrome appearing after prolonged dopamine receptor blocking treatment

What is tardive akathisia

A delayed persistent akathisia syndrome associated with prolonged dopamine receptor blocking treatment

What is the defining timing feature of tardive syndromes

They emerge late in treatment and can persist after medication reduction or discontinuation

What is medication induced postural tremor

A fine rhythmic tremor that appears while maintaining a posture after medication exposure

Where is medication induced postural tremor commonly seen

Hands and fingers

What medications can cause postural tremor

Lithium / stimulants / antidepressants / valproate / caffeine related drugs / other medications

How fast is medication induced postural tremor commonly

About 8 to 12 cycles per second

How does postural tremor differ from parkinsonian tremor

Postural tremor occurs while maintaining a posture while parkinsonian tremor is most characteristic at rest

What is other medication induced movement disorder

A medication related movement syndrome that does not fit one of the specifically named movement disorders

What is antidepressant discontinuation syndrome

Physical and psychological symptoms caused by stopping or significantly reducing an antidepressant

What increases the risk of antidepressant discontinuation syndrome

Abrupt discontinuation / rapid dose reduction / short medication half life

Which antidepressants in the chapter are especially associated with discontinuation symptoms

Paroxetine and venlafaxine

Which antidepressant is less likely to cause major discontinuation symptoms because of its long half life

Fluoxetine

When do antidepressant discontinuation symptoms usually begin

About 2 to 4 days after the last dose

What symptoms can occur after SSRI discontinuation

Dizziness / tinnitus / electric shock like sensations / insomnia / acute anxiety

How long do antidepressant discontinuation symptoms usually last

Usually no more than about 2 weeks

Can antidepressant discontinuation syndrome occur with intermittent missed doses

Yes especially with short half life medications

Does antidepressant discontinuation syndrome involve drug craving

No

Why is antidepressant discontinuation syndrome not considered a substance withdrawal disorder

Antidepressants do not produce reinforcing or euphoric effects and patients generally do not show compulsive drug seeking

What is an important differential for antidepressant discontinuation syndrome

Relapse of the depression or anxiety disorder being treated