Artane

Artane (trihexyphenidyl hydrochloride) is a centrally acting anticholinergic agent indicated for the treatment of parkinsonism and the control of extrapyramidal disorders. It functions as a competitive antagonist at muscarinic acetylcholine receptors, effectively counteracting the relative cholinergic excess that characterizes these movement disorders. This agent is a cornerstone in the management of drug-induced extrapyramidal symptoms, particularly those associated with antipsychotic medications, and serves as an adjunctive therapy in all forms of parkinsonism. Its therapeutic action helps rebalance neurotransmitter activity in the basal ganglia, leading to a significant reduction in tremor, rigidity, and sialorrhea, thereby improving functional mobility and quality of life for patients.

Features

• Active Pharmaceutical Ingredient: Trihexyphenidyl Hydrochloride
• Available Formulations: 2 mg and 5 mg immediate-release tablets; 5 mg sustained-release capsules; Elixir (2 mg/5mL)
• Pharmacologic Class: Anticholinergic (Antimuscarinic) Agent
• Mechanism of Action: Competitive inhibition of acetylcholine at central muscarinic receptors
• Half-life: Approximately 3.3 - 4.1 hours (immediate-release)
• Time to Peak Plasma Concentration: 1-1.3 hours (fasting)
• Metabolism: Hepatic, via hydroxylation
• Excretion: Primarily renal

Benefits

• Reduction of Parkinsonian Tremor and Rigidity: Effectively diminishes the characteristic pill-rolling tremor and muscular stiffness, facilitating smoother and more controlled voluntary movements.
• Management of Drug-Induced Extrapyramidal Symptoms (EPS): Provides rapid relief from acute dystonic reactions, akathisia, and pseudoparkinsonism caused by typical antipsychotic drugs, often allowing for the continuation of necessary neuroleptic therapy.
• Decreased Sialorrhea (Drooling): Its anticholinergic properties reduce excessive saliva production, a common and socially debilitating symptom of parkinsonism.
• Adjunctive Therapy in Parkinson’s Disease: Used in combination with levodopa/carbidopa, it can help manage symptoms, potentially allowing for lower doses of levodopa and mitigating some of its long-term side effects.
• Improved Functional Capacity and Quality of Life: By alleviating key motor symptoms, it enables patients to perform activities of daily living with greater independence and confidence.

Common use

Artane is primarily prescribed for the treatment of all forms of parkinsonism, including post-encephalitic, arteriosclerotic, and idiopathic Parkinson’s disease. Its most frequent application in modern practice is for the prevention and treatment of drug-induced extrapyramidal symptoms (EPS) such as dystonia, akathisia, and parkinsonian features, which are adverse effects associated with first-generation (typical) antipsychotic medications (e.g., haloperidol, chlorpromazine). It is also used off-label for the treatment of focal dystonias, like cervical dystonia (spasmodic torticollis), and to reduce sialorrhea in various neurological conditions.

Dosage and direction

Dosage must be individualized based on the condition being treated, severity of symptoms, patient age, and tolerance. Therapy should be initiated at a low dose and titrated upward gradually.

• For Drug-Induced Extrapyramidal Symptoms: The usual initial dose is 1 mg on the first day. The dose may be increased by 2 mg increments at intervals of 3 to 5 days until satisfactory control is achieved. The usual daily range is 5 to 15 mg, though more severe cases may require higher doses. Once control is achieved, the dose should be reduced to the lowest effective maintenance level.
• For Parkinson’s Disease: The total daily dose typically ranges from 6 mg to 10 mg, divided into three or four doses. Some patients may benefit from up to 12-15 mg per day. The sustained-release formulation (5 mg capsule) is usually administered twice daily (every 12 hours).
• Elderly Patients: Geriatric patients often require lower dosages due to increased susceptibility to anticholinergic effects (e.g., confusion, drowsiness). Initiation at 0.5 mg to 1 mg at bedtime is common, with very cautious titration.
• Administration: Tablets should be taken with or after food to minimize gastric upset. The sustained-release capsules must be swallowed whole and not crushed, chewed, or divided.

Precautions

• Use in Geriatrics: Elderly patients are extremely sensitive to the CNS effects of anticholinergics. They are at significantly increased risk for confusion, agitation, hallucinations, drowsiness, and psychiatric disturbances. Dosing must be conservative.
• Mental Alertness: Artane may impair mental and/or physical abilities required for the performance of hazardous tasks, such as operating machinery or driving a motor vehicle. Patients should be cautioned accordingly.
• Tapering Discontinuation: Abrupt withdrawal after prolonged use may lead to a exacerbation of parkinsonian symptoms or neuroleptic malignant syndrome. Dosage should be tapered gradually, especially in patients concurrently using antipsychotics.
• Environmental Temperature: Artane can suppress sweating, leading to decreased heat tolerance and an increased risk of heat stroke or hyperthermia, particularly in hot weather.
• Underlying Conditions: Use with extreme caution in patients with known or suspected glaucoma (particularly angle-closure), prostatic hypertrophy, obstructive disease of the gastrointestinal or genitourinary tracts, cardiac arrhythmias, and liver or kidney disease.
• Tardive Dyskinesia: Artane can mask the early signs of tardive dyskinesia, a potentially irreversible hyperkinetic movement disorder associated with antipsychotic use.

Contraindications

Artane is contraindicated in patients with:

• Known hypersensitivity to trihexyphenidyl hydrochloride or any component of the formulation.
• Narrow-angle glaucoma (can precipitate an acute attack).
• Bowel obstruction, including paralytic ileus.
• Myasthenia gravis.
• Severe ulcerative colitis or toxic megacolon.
• Obstructive uropathy (e.g., bladder neck obstruction due to prostatic hypertrophy).

Possible side effect

Side effects are primarily extensions of its anticholinergic pharmacology and are often dose-related.

• Common: Dry mouth, blurred vision, constipation, nausea, dizziness, drowsiness, urinary hesitancy or retention.
• Less Common: Nervousness, insomnia, headache, tachycardia, palpitations, dilated pupils, increased intraocular pressure, weakness, vomiting, skin rash.
• Serious (Require Medical Attention): Mental confusion, agitation, hallucinations (especially in the elderly), psychotic episodes, depression, short-term memory problems, numbness of fingers, eye pain (possible sign of acute glaucoma), difficulty swallowing, hyperthermia.

Drug interaction

Artane has the potential for significant pharmacodynamic interactions.

• Other Anticholinergics: Concomitant use with other drugs possessing anticholinergic properties (e.g., antihistamines, tricyclic antidepressants like amitriptyline, phenothiazines, disopyramide) will have additive effects, increasing the risk and severity of side effects.
• CNS Depressants: Effects may be additive with alcohol, benzodiazepines, opioids, and sedating antihistamines, leading to increased drowsiness and sedation.
• Absorption of Other Drugs: By decreasing gastrointestinal motility, Artane may affect the absorption rate of other orally administered drugs.
• Levodopa: The combination is synergistic for treating parkinsonism, but the side effect profiles (CNS, gastrointestinal) can be additive.
• Haloperidol: Artane may reduce the serum concentration of haloperidol, potentially diminishing its antipsychotic efficacy.
• Antacids/Antidiarrheals: May interfere with the absorption of Artane. Dosing should be separated by several hours.

Missed dose

If a dose is missed, it should be taken as soon as it is remembered. However, if it is almost time for the next scheduled dose, the missed dose should be skipped, and the regular dosing schedule resumed. The patient should not double the dose to make up for a missed one.

Overdose

Overdose with Artane is characterized by intensification of its known pharmacological effects.

• Symptoms: Severe central nervous system disturbances (agitation, confusion, hallucinations, psychosis, seizures), severe dizziness, syncope, tachycardia, fever, hot/dry/flushed skin, respiratory depression, paralysis, and coma.
• Management: This is a medical emergency requiring immediate hospitalization. Treatment is primarily supportive and symptomatic. Gastric lavage or activated charcoal may be considered if ingestion was recent. Physostigmine, a cholinesterase inhibitor, may be used as an antidote in severe, life-threatening cases but carries its own risks (e.g., seizures, bradycardia) and must be administered with extreme caution. Temperature control, management of arrhythmias, and respiratory support are critical.

Storage

Store at controlled room temperature, 20°C to 25°C (68°F to 77°F). Protect from light and moisture. Keep the container tightly closed. Keep all medications out of the reach of children and pets. Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed.

Disclaimer

This information is for educational and informational purposes only and does not constitute medical advice. It is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition or medication. Never disregard professional medical advice or delay in seeking it because of something you have read here. The information provided is not all-inclusive and describes the typical use of this medication; it may not contain all available information about the possible uses, directions, warnings, precautions, interactions, adverse effects, or risks.

Reviews

• Clinical Efficacy (4.5/5): “As a movement disorder specialist, Artane remains a first-line tool for acute dystonic reactions. Its rapid onset and efficacy are undeniable. Titration is key to balancing benefit with the often-troublesome anticholinergic side effects.”
• Tolerability (3/5): “The side effect profile is significant. Dry mouth and blurred vision are almost universal at therapeutic doses. We use it out of necessity for EPS, but patient counseling on what to expect is paramount to adherence.”
• Geriatric Use (2/5): “Extreme caution is warranted in the elderly population. The risk of inducing delirium, confusion, and hallucinations is high. We rarely initiate it in patients over 70 and only at micro-doses if absolutely necessary, with frequent monitoring.”
• Functional Improvement (4/5): “For my younger patients with antipsychotic-induced parkinsonism, Artane has been a game-changer. It allowed them to continue their necessary psychiatric medication while regaining motor control and reducing the tremors that were impacting their daily lives.”