PERKINIL 5 TABLET

Indications

• Symptomatic Parkinsonism
• Extrapyramidal dysfunction caused by antipsychotic medications

Dosage

Children: Refer to the BNF for Children for specific dosage recommendations.

Adults: Refer to the BNF for specific dosage recommendations.

Mechanism of action

Procyclidine is thought to act primarily by blocking central cholinergic receptors, which helps to restore the balance between cholinergic and dopaminergic activity in the basal ganglia. Its effects are comparable to those of atropine, providing antispasmodic effects on smooth muscle, producing mydriasis, and reducing salivation.

Pharmacodynamics

Procyclidine exhibits atropine-like action, particularly on parasympathetic-innervated structures, including smooth muscle. Its antispasmodic properties are attributed to the blockade of cholinergic receptors M1, M2, and M4 in the central nervous system. This action is beneficial in treating symptomatic Parkinsonism and the extrapyramidal side effects caused by antipsychotic drugs.

Pharmacokinetics

The pharmacokinetics of procyclidine have not been extensively detailed, but it is known to be well absorbed when administered orally. The drug is distributed throughout the body and crosses the blood-brain barrier, leading to its central nervous system effects. Metabolism and elimination details are less defined and should be considered when prescribing.

Interactions

• paroxetine+procyclidine: Moderate (increases exposure)
• clozapine+procyclidine: Unknown (additive effect)
• antipsychotics, second-generation+procyclidine: Unknown (additive effect)

Pregnancy

Procyclidine should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.

Breast-feeding

Caution is advised when procyclidine is administered to a breastfeeding woman, as it is unknown if it is excreted in human milk.

Storage

Store in a cool, dry place, away from light. Keep out of reach of children.

Formulations

• Procyclidine hydrochloride tablets
• Procyclidine hydrochloride oral solution

Indications

• Parkinsonism
• Drug-induced extrapyramidal symptoms (excluding tardive dyskinesia)
• Acute dystonia

Dosage

Children: For children, the dosage may vary based on age and specific condition. Refer to the BNF for Children for appropriate dosing schedules and adjustments.

Adults: For Parkinsonism, the usual initial dose is 2.5 mg three times a day, with gradual increments of 2.5-5 mg as needed, and a typical maintenance dose of 10-30 mg daily in divided doses. Maximum daily doses should not exceed 60 mg. For acute dystonia, an initial dose of 5-10 mg may be administered by intramuscular or intravenous injection, with a maximum of 20 mg per day.

Mechanism of action

Procyclidine hydrochloride functions as a competitive antagonist of muscarinic acetylcholine receptors. By inhibiting the action of acetylcholine, it reduces the relative cholinergic overactivity that occurs in conditions associated with dopamine deficiency, such as Parkinson's disease and acute dystonia.

Pharmacodynamics

Procyclidine exhibits anticholinergic properties, leading to reduced muscle rigidity and tremors associated with parkinsonism and other movement disorders. Its effectiveness in alleviating acute dystonia has also been well documented, facilitating smoother muscle control and less involuntary movement.

Pharmacokinetics

Procyclidine is well absorbed after oral administration, with peak plasma concentrations typically achieved within 1-2 hours. It is extensively metabolized in the liver, and its elimination half-life ranges from 6 to 12 hours. The drug is primarily excreted through the kidneys. Caution is advised in patients with hepatic or renal impairment due to altered drug metabolism and clearance.

Contra-indications

• Gastro-intestinal obstruction
• Myasthenia gravis

Adverse effects

• Memory loss
• Cognitive impairment
• Constipation
• Dry mouth
• Blurred vision
• Urinary retention
• Dizziness
• Nausea

Precautions

• Caution in patients with cardiovascular disease
• Caution in elderly patients
• Caution in patients with hypertension
• Caution in patients with dementia
• Use with caution in hepatic impairment
• Use with caution in renal impairment
• Avoid abrupt withdrawal in patients taking long-term treatment

Pregnancy

Caution is advised during pregnancy due to potential effects on the fetus.

Breast-feeding

Caution is advised during breastfeeding as it may affect the infant.

Storage

Store in a cool, dry place away from direct sunlight. Keep out of reach of children.

Formulations

• Procyclidine hydrochloride 5 mg tablets
• Procyclidine hydrochloride 500 microgram per 1 ml oral solution
• Procyclidine hydrochloride 5 mg per 1 ml injection solution

Mechanism of action

The mechanism of action is unknown. It is thought that Procyclidine acts by blocking central cholinergic receptors, and thus balancing cholinergic and dopaminergic activity in the basal ganglia. Many of its effects are due to its pharmacologic similarities with atropine. Procyclidine exerts an antispasmodic effect on smooth muscle, and may produce mydriasis and reduction in salivation. Pharmacologic tests have shown that procyclidine hydrochloride has an atropine-like action and exerts an antispasmodic effect on smooth muscle. It is a potent mydriatic and inhibits salivation. It has no sympathetic ganglion- blocking activity in doses as high as 4 mg/kg, as measured by the lack of inhibition of the response of the nictitating membrane to preganglionic electrical stimulation.

Pharmacodynamics

Procyclidine has an atropine-like action on parasympathetic-innervated peripheral structures including smooth muscle. It's antispasmodic effects are thought to be related to the blockage of central cholinergic receptors M1, M2 and M4. It is used to treat symptomatic Parkinsonism and extrapyramidal dysfunction caused by antipsychotic agents.