Drugs used in Parkinsonism and related Disorders

In idiopathic Parkinson’s disease, the progressive degeneration of pigmented neurones in the substantia nigra leads to a deficiency of the neurotransmitter dopamine. The resulting neurochemical imbalance in the basal ganglia causes the characteristic signs and symptoms of the illness. Drug therapy does not prevent disease progression, but it improves most patients’ quality of life. Treatment is usually not started until symptoms cause significant disruption of daily activities.

Dopaminergic drugs used in Parkinsonism

BROMOCRIPTINE:

Indications: Parkinsonism (but not drug-induced extrapyramidal symptoms).

Contraindications: Eclampsia of Pregnancy, Lactating Mother, Mild Pre­Eclampsia, Pregnancy-Induced Hypertension, Severe Pre-Eclampsia, Severe Uncontrolled Hypertension, Cerebrovascular Accident, Coronary Artery Disease, Hypertension, Psychiatric Disturbance.

Dose and Administration: First week 1–1.25 mg at night, second week 2– 2.5 mg at night, third week 2.5 mg twice daily, fourth week 2.5 mg 3 times daily then increasing by 2.5 mg every 3–14 days according to response to a usual range of 10–40 mg daily; taken with food.

PRAMIPEXOLE:

Indications: Parkinson’s disease, used alone or as an adjunct to levodopa with dopa-decarboxylase inhibitor; moderate to severe restless legs syndrome.

Contraindications: breast-feeding it May suppress lactation.

Dose and Administration: Parkinson’s disease, initially 88 micrograms 3 times daily, dose doubled every 5–7 days if tolerated to 350 micrograms 3 times daily; further increased if necessary by 180 micrograms 3 times daily at weekly intervals; max. 3.3 mg daily in 3 divided doses. During pramipexole dose titration and maintenance, levodopa dose may be reduced. Restless legs syndrome, initially 88 micrograms once daily 2–3 hours before bedtime, dose doubled every 4–7 days if necessary to 350 micrograms daily; max. 540 micrograms daily; child under 18 years not recommended.

LEVODOPA-CARBIDOPA:

Indications: Idiopathic Parkinsonism, Parkinsonism, Postencephalitic Parkinsonism, Restless Legs Syndrome.

Contraindications: Malignant Melanoma, Narrow Angle Glaucoma, Conduction Disorder of the Heart, Depression, Drug-Induced Psychosis, Duodenal Ulcer, Dyskinesia, Gastric Ulcer, Gastrointestinal Hemorrhage, Myocardial Infarction, Peptic Ulcer, Psychotic Disorder, Pulmonary Disease, Renal Disease, Severe Cardiovascular Disease, Suicidal Ideation.

Dose and Administration: Expressed as levodopa, initially 100 mg (with carbidopa 25 mg) 3 times daily, increased by 50–100 mg (with carbidopa 12.5– 25 mg) daily or on alternate days according to response, up to 800 mg (with carbidopa 200 mg) daily in divided doses. Alternatively, initially 50–100 mg (with carbidopa 10–12.5 mg) 3–4 times daily, increased by 50–100 mg daily or on alternate days according to response, up to 800 mg (with carbidopa 80–100 mg) daily in divided doses. Alternatively, initially 125 mg (with carbidopa 12.5 mg, as 1/2 tablet of co-careldopa 25/250) 1–2 times daily, increased by 125 mg (with carbidopa 12.5 mg) daily or on alternate days according to response.

ENTACAPONE:

Indications: adjunct to levodopa with dopa-decarboxylase inhibitor in Parkinson’s disease and ‘end-of-dose’ motor fluctuations.

Contraindications: pregnancy; breast-feeding; hepatic impairment; phaeochromocytoma; history of neuroleptic malignant syndrome or non-traumatic rhabdomyolysis.

Dose and Administration: 200 mg with each dose of levodopa with dopa­decarboxylase inhibitor; max. 2 g daily.

LEVODOPA-CARBIDOPA- ENTACAPONE:

Indications: Idiopathic Parkinsonism.

Contraindications: Malignant Melanoma, Narrow Angle Glaucoma, Conduction Disorder of the Heart, Depression, Drug-Induced Psychosis, Duodenal Ulcer, Dyskinesia, Gastric Ulcer, Gastrointestinal Hemorrhage, Myocardial Infarction, Peptic Ulcer, Psychotic Disorder, Pulmonary Disease, Renal Disease, Severe Cardiovascular Disease, Suicidal Ideation.

Dose and Administration: Only 1 tablet to be taken for each dose; max. 10 tablets daily.

PIRIBEDIL:

Indications: Treatment of Parkinson’s disease (PD), either as monotherapy (without L-DOPA (Levodopa)) or in combination with L-DOPA therapy, in the early stages as well as in the advanced stages of the disease. Treatment of pathological cognitive deficits in the elderly (impaired attention, motivation, memory, etc). Treatment of dizziness in the elderly. Adjuvant treatment in intermittent claudication due to peripheral vascular disease (PVD) of the lower limbs.

Contraindications: Circulatory collapse, acute myocardial infarction.

Dose and Administration: Administration of piribedil should be initiated with one tablet daily during the first week. Dosage should then be gradually increased every week until achieving the optimal therapeutic dose. as monotherapy: three to five tablets in three to five doses daily. in combination with L-dopa therapy: one to three tablets daily.

Antimuscarinic drugs used in parkinsonism

PROCYCLIDINE HYDROCHLORIDE:

Indications: Parkinsonism; drug-induced extrapyramidal symptoms.

Contraindications: Antimuscarinics should be avoided in gastro-intestinal obstruction and myasthenia gravis.

Dose and Administration: By mouth, 2.5 mg 3 times daily, increased gradually in steps of 2.5–5 mg daily every 2–3 days if necessary; usual max. 30 mg daily in 2–4 divided doses (60 mg daily in exceptional circumstances); elderly preferably lower end of range. By intramuscular or intravenous injection, acute dystonia, 5–10 mg (occasionally more than 10 mg), usually effective in 5– 10 minutes but may need 30 minutes for relief; elderly preferably lower end of range.

Drugs used in essential tremor, chorea, tics, and related disorders

PIRACETAM:

Indications: adjunctive treatment of cortical myoclonus.

Contraindications: cerebral haemorrhage; hepatic impairment; pregnancy; breast-feeding.

Dose and Administration: Initially 7.2 g daily in 2–3 divided doses, increased according to response by 4.8 g daily every 3–4 days to max. 20 g daily (subsequently, attempts should be made to reduce dose of concurrent therapy); child under 16 years not recommended

Torsion dystonias and other involuntary movements:

BOTULINUM TOXIN TYPE A:

Indications: to treat the abnormal head position and neck pain that happens with cervical dystonia (CD) in adults. To treat certain types of eye muscle problems (strabismus) or abnormal spasm of the eyelids (blepharospasm) in people 12 years and older.

Contraindications: generalised disorders of muscle activity (e.g. myasthenia gravis).

Dose and Administration: 50 Units in each injection site and to not exceed 200 units during the first treatment session.