Haloperidol

Akathasia

REF: Kaplan ^9th ed p. 1050, Goodman & Gillman 2008 edition page 304

HALOPERIDOL TOXICITY:

i. Cardiac depressant:

• QT prolongation
• Torsades de pointes

ii.    Weight gain

iii.   Sedation

iv.   Anticholinergic side effects: (dry mouth, constipation, paralytic ileus, difficulties in urinating, massive sweating)

v.    Adverse neurological syndromes: (Extra pyramidal effects common to most antipsychotic) 

NEUROLEPTIC INDUCED DISORDERS

0= Onset, I= incidence, M= Mechanism, RF= Risk factors, S= Symptoms, T=Treatment

Long QT

Akathisia refers to somatic restlessness which occur in patients treated with first generation antipsychotics.

Among the options given haloperidol is an old generation antipsychotic which causes a side effect of akathisia.

Drugs commonly used to treat akathisia are propranolol, benzodiazepines and anticholinergics.

Symptoms of haloperidol toxicity are usually due to exaggerated side effects. Most often encountered are:

• Severe extrapyramidal side effects with muscle rigidity and tremors, akathisia, etc.
• Hypotension or hypertension
• Sedation
• Anticholinergic side effects (dry mouth, constipation, paralytic ileus, difficulties in urinating, decreased perspiration)
• Coma in severe cases, accompanied by respiratory depression and massive hypotension, shock
• Rarely, serious ventricular arrhythmia (torsades de pointes), with or without prolonged QT-time
• Epileptic seizures

Akathisia is a term coined by Haskovec in 1904 to describe an inner feeling of restlessness, an inability to sit still, and a compulsion to move about.

When sitting, the patient constantly shifts his body and legs, crosses and uncrosses his legs, and swings the free leg.

Running in place and persistent pacing are also characteristic.

This abnormality of movement is most prominent in the lower extremities and may not be accompanied, at least in mild forms of akathisia, by perceptible rigidity or other neurologic abnormalities.

First noted in patients with Parkinson disease and senile dementia, akathisia is now observed most often in patients receiving neuroleptic drugs. This disorder can be induced in normal individuals by the administration of neuroleptic drugs or L-dopa.

Haloperidol is a high potency antipsychotic and extra pyramidal disturbances (Akathasia, Acute dystonia, Parkinsonism) are the major/most common reported side effects associated with its use.

Ref: Essentials of Pharmacology by KD Tripathi, 5th Edition, Page 377; The Evidence-Based Guide to Antipsychotic Medications edited by Anthony J. Rothschild, 2010, Page 176; Kaplan and Sadock’s Psychiatry, 9th Edition, Page 1055.

A, B, C .e. Haloperidol, Risperidone, Olanazepine

D i.e. Akathisia

C i.e. Addition of B blocker

B i.e. Propranolol

A i.e. Acute dystonia

B i.e. Neuroleptic malignant syndrome

C i.e. Neuroleptic malignant syndrome

A i.e. Trifluperazine; B i.e. Clozapine; C i.e. Haloperidol

D i.e. Haloperidol

• The diagnosis of this lady is morbid grief
•  When there is an exaggeration of one or more symptoms of normal grief or the duration becomes prolonged beyond 6 months without recovery, it is k/a morbid grief.
• Preoccupation with the memory of deceased is a characteristic featureQ.
• Idealization of deceased (ignoring his negative qualities).
• Sense of presence of deceased in the surroundings & misinterpretation of voices or faces of others as that of lost person. Rarely fleeting hallucinations may occur.
• Treatment – In morbid & complicated grief, medication depends on presenting clinical features.

As this lady is mainly having problem of auditory hallucination (1/t sadness & anxiety) – antipsychotic like haloperidol is needed to treat her.

Ans. is ‘d’ i.e., Haloperidol

Antagonism of dopamine actions

o As the receptors stimulated by dopamine are different at different rates of infusion, the antagonists are different for different rates of infusion.

Antagonism of renal dose

o Low rates of dopamine infusion cause stimulation of dopamine receptors and produce vasodilatation of renal and mesentric blood vessels.

o This vasodilatation of dopamine is not antagonised by the J3-adrenoreceptor blockers (as this renal effect is not mediated by [3-receptors).

o However this vasodilatation of renal vessels is antagonized by halopridol and other dopamine receptor blocking agents.

Antagonism of intermediate dose

o The infusion of moderately higher concentrations of dopamine increases the rate and contractile force of the heart and augments the cardiac output.

o This action is mediated by p_iadrenoreceptor and due to nor-adrenaline release, and is antagonized by propranolol. Antagonism of higher doses

o At still higher concentrations, dopamine causes a-adrenoreceptor – mediated vasoconstriction in most vascular beds and stimulates the heart.

o The vasoconstrictive action of dopamine is antagonized by a-adrenoreceptor blocking agents such as phentolamine.

Ans. is ‘a’ i.e., Acute drug dystonia

o Persistent deviation of neck (Torticollis) after one day of taking haloperidol is a feature of acture muscular dystonia (acute drug dystonia).

Acute muscular dystonia

o Bizarre muscle spasms mostly involving linguo-facial muscles –> grimacing, tongue thrusting, torticollis, locked jaw.

o Occurs within a few hours of a single dose.

o More common in children below 10 years and girls.

o Treatment —> central anticholinergic

Ans. is ‘a’ i.e., Haloperidol

Drugs causing extrapvramidal effects

o Butyrophenones (Haloperidol)             o Methyldopa                o OCP’S                     o Reserpine

o Levodopa                                      o Metoclopromide           o Phenothiazines          o Tricyclic Antidepressants