Artane (trihexyphenidyl hydrochloride) is a centrally acting anticholinergic agent indicated for the treatment of parkinsonism and drug-induced extrapyramidal reactions. It functions as a competitive antagonist at muscarinic acetylcholine receptors, effectively counteracting the relative central cholinergic excess that contributes to the motor dysfunction seen in these conditions. By modulating neurotransmitter balance in the basal ganglia, Artane helps alleviate tremor, rigidity, and sialorrhea, thereby improving functional mobility and quality of life for appropriate patients under strict medical supervision.

Features

• Active Pharmaceutical Ingredient: Trihexyphenidyl Hydrochloride
• Available Dosage Forms: 2 mg and 5 mg scored tablets; 2 mg/5 mL elixir
• Pharmacologic Class: Anticholinergic (Antimuscarinic) Agent
• Mechanism of Action: Competitive antagonism of central and peripheral muscarinic acetylcholine receptors
• Half-life: Approximately 3.3 - 4.1 hours in healthy adults
• Bioavailability: High oral bioavailability, not significantly affected by food
• Metabolism: Hepatic, via hydroxylation
• Excretion: Primarily renal

Benefits

• Reduction of Parkinsonian Tremor and Rigidity: Effectively diminishes the characteristic resting tremor and muscle stiffness associated with parkinsonism, facilitating smoother and more controlled voluntary movements.
• Management of Drug-Induced Extrapyramidal Symptoms (EPS): Provides rapid relief from acute dystonic reactions, akathisia, and pseudoparkinsonism often caused by typical antipsychotic medications (e.g., haloperidol), allowing for continued necessary psychiatric treatment.
• Improved Functional Mobility and Gait: By alleviating rigidity and promoting motor control, patients often experience a significant improvement in their ability to walk, perform activities of daily living, and maintain independence.
• Decreased Sialorrhea (Drooling): Its anticholinergic properties reduce salivary secretions, which is a common and socially limiting symptom in parkinsonian syndromes.
• Adjunctive Therapy in Dystonia: Can be used as part of a comprehensive treatment plan for certain forms of dystonia, helping to reduce abnormal, sustained muscle contractions.

Common use

Artane is primarily prescribed for the symptomatic treatment of all forms of parkinsonism, including post-encephalitic, arteriosclerotic, and idiopathic Parkinson’s disease. It is often used as monotherapy in mild cases or as an adjunct to levodopa therapy in more advanced disease to manage symptoms that are not fully controlled. Its second major indication is for the treatment of drug-induced extrapyramidal symptoms (EPS) caused by neuroleptic agents (antipsychotics), particularly effective for acute dystonic reactions. It may also be used off-label for the treatment of focal dystonias, such as cervical dystonia (spasmodic torticollis), and to reduce sialorrhea in various neurological conditions.

Dosage and direction

Dosage must be individualized and titrated slowly to achieve optimal effect with minimal side effects. Therapy is typically initiated at a low dose and gradually increased.

For Drug-Induced Extrapyramidal Symptoms:

• Initial dose: 1 mg orally per day.
• Increase gradually in 2 mg increments at intervals of 3-5 days until satisfactory control is achieved.
• The usual maintenance dose is 5-15 mg per day, given in divided doses (3-4 times daily). Most patients respond to 5-7 mg daily. The need for continued therapy should be reassessed periodically.

For Parkinsonism:

• Day 1: 1 mg orally after breakfast.
• Day 2: 1 mg after breakfast and 1 mg after lunch.
• Day 3: 1 mg after breakfast, 1 mg after lunch, and 1 mg after evening meal.
• Subsequent increases: Increase by 1 mg every 3-5 days until a total daily dose of 6-10 mg is reached.
• Many patients derive maximum benefit from a total daily dose of 6-10 mg, though some may require up to 12-15 mg daily.
• The total daily dose should be divided into 3-4 doses, administered with meals or shortly thereafter to minimize gastric upset. The last dose should be given before evening to reduce the risk of nighttime confusion.

Elderly Patients: A more conservative dosing strategy is mandatory. Initiate therapy at 1 mg once daily at bedtime, with very slow titration (e.g., 1 mg increments weekly) and close monitoring for cognitive and psychiatric adverse effects. The maximum dose in the elderly is often significantly lower.

Precautions

• Cognitive Impairment: Artane can cause confusion, memory impairment, and exacerbation of dementia. Use with extreme caution in patients with pre-existing cognitive deficits or elderly patients, who are particularly susceptible.
• Glaucoma: This drug can induce pupillary dilation (mydriasis) and increase intraocular pressure. It is contraindicated in patients with angle-closure glaucoma and must be used with great caution in patients with open-angle glaucoma, only under close ophthalmologic supervision.
• Prostatic Hypertrophy: Artane may cause urinary retention and hesitancy due to its anticholinergic effects on the bladder. It should be used cautiously in men with known prostatic hypertrophy.
• Tachycardia: May cause palpitations and tachycardia. Caution is advised in patients with cardiac arrhythmias, coronary artery disease, or congestive heart failure.
• Gastrointestinal Conditions: Can decrease gastrointestinal motility. Use with caution in patients with ulcerative colitis, intestinal atony, or paralytic ileus. It may also aggravate gastroesophageal reflux disease (GERD).
• Hyperthyroidism: Patients with hyperthyroidism may have an increased sensitivity to the cardiovascular effects (tachycardia) of anticholinergics.
• Renal/Hepatic Impairment: Dosage adjustment may be necessary in patients with significant renal or hepatic impairment, as the drug is metabolized and excreted through these pathways.
• Pregnancy and Lactation: Artane should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. It is excreted in human milk and may suppress lactation; a decision should be made to discontinue nursing or discontinue the drug.
• Abrupt Withdrawal: Abrupt discontinuation after prolonged use may lead to a exacerbation of parkinsonian symptoms or withdrawal symptoms. Tapering the dose gradually is recommended.
• Heat Prostration: Use in hot weather may lead to heatstroke and fever due to decreased sweating.

Contraindications

Artane is contraindicated in patients with:

• Known hypersensitivity to trihexyphenidyl hydrochloride or any component of the formulation.
• Angle-closure glaucoma (narrow-angle glaucoma).
• Obstructive diseases of the gastrointestinal tract (e.g., paralytic ileus, intestinal atony, severe ulcerative colitis, toxic megacolon).
• Obstructive uropathy (e.g., bladder neck obstruction due to prostatic hypertrophy).
• Myasthenia gravis.
• Significant tachycardia unstable cardiovascular status in acute hemorrhage.

Possible side effect

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

• Common: Dry mouth (xerostomia), blurred vision, pupillary dilation, constipation, nausea, urinary hesitation or retention.
• Central Nervous System: Dizziness, lightheadedness, drowsiness, nervousness, insomnia, confusion, euphoria, agitation, hallucinations (especially in the elderly), memory impairment, worsening of pre-existing dementia.
• Cardiovascular: Tachycardia, palpitations.
• Dermatological: Decreased sweating, rash.
• Ophthalmic: Increased intraocular pressure, cycloplegia.
• Gastrointestinal: Vomiting, paralytic ileus.
• Other: Weakness, headache.

Drug interaction

Artane has the potential for significant pharmacodynamic interactions with other drugs possessing anticholinergic activity, leading to additive side effects.

• Other Anticholinergics: Concurrent use with other drugs having anticholinergic properties (e.g., antihistamines like diphenhydramine, tricyclic antidepressants like amitriptyline, phenothiazines, disopyramide) can profoundly increase the risk of severe constipation, urinary retention, blurred vision, hyperthermia, and confusion.
• Cholinergic Agents: Artane will antagonize the effects of cholinergic agonists (e.g., bethanechol) and acetylcholinesterase inhibitors (e.g., donepezil, rivastigmine).
• CNS Depressants: May have additive sedative effects with alcohol, benzodiazepines, opioids, and other sedating drugs, increasing the risk of dizziness and impaired alertness.
• Absorption of Other Drugs: By decreasing gastrointestinal motility, Artane may affect the absorption rate of other orally administered drugs.
• Dopaminergics: When used with levodopa, the dosages of both drugs must be adjusted carefully for optimal effect and to manage side effects.
• Haloperidol: Artane may reduce serum concentrations of haloperidol, potentially decreasing its efficacy, though it is used to treat its EPS.
• Ketoconazole & Other CYP3A4 Inhibitors: May increase the plasma concentration of trihexyphenidyl.

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. The patient should not take a double dose to make up for the missed one. Maintaining a consistent dosing schedule is important for stable symptom control.

Overdose

Overdose with Artane is characterized by intensification of its pharmacological effects and constitutes a medical emergency. Symptoms progress from central nervous system stimulation to depression.

• Symptoms: Severe central anticholinergic syndrome including hallucinations, psychosis, severe confusion, agitation, seizures, respiratory depression, and coma. Peripheral effects include hyperthermia (hot, dry, flushed skin), dilated pupils, blurred vision, tachycardia, hypertension, urinary retention, diminished bowel sounds, and ileus.
• Management: Immediate gastric lavage or administration of activated charcoal if ingestion was recent. Treatment is primarily supportive and symptomatic. The specific antidote for central anticholinergic toxicity is physostigmine salicylate, a reversible acetylcholinesterase inhibitor, which may be administered by trained medical personnel in a controlled hospital setting. However, its use is reserved for severe life-threatening symptoms due to its own risk of serious side effects (e.g., seizures, bradycardia). Supportive care includes temperature control, management of arrhythmias, and respiratory support.

Storage

Store Artane tablets and elixir at controlled room temperature, 20°C to 25°C (68°F to 77°F). Keep the container tightly closed to protect from light and moisture. Keep out of reach of children and pets. Do not use after the expiration date printed on the packaging. Do not flush medications down the toilet or pour them into a drain unless instructed to do so.

Disclaimer

This information is for educational and informational purposes only and 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 content has been compiled from various sources believed to be accurate but cannot be guaranteed. The author and publisher disclaim any liability for any adverse effects resulting directly or indirectly from the use of the information contained herein.

Reviews

• “As a movement disorder specialist, Artane remains a valuable tool in my arsenal, particularly for managing antipsychotic-induced dystonia. The rapid onset of action is crucial in emergency settings. However, its cognitive side effect profile demands vigilant patient selection and monitoring, especially in the elderly population.” — Neurologist, 15 years experience.
• “Prescribing Artane requires a delicate balance. For my Parkinson’s patients who cannot tolerate amantadine or need additional symptom control, it can be effective for tremor. The key is ‘start low, go slow.’ Patient education on managing dry mouth and constipation is part of the essential conversation.” — Geriatrician.
• “The efficacy of trihexyphenidyl for acute dystonic reactions is undeniable. We see dramatic relief within 30-60 minutes of intramuscular administration in the ER. Its use, however, is typically short-term in these cases to avoid long-term anticholinergic burden.” — Emergency Medicine Physician.
• “From a patient perspective, Artane helped significantly with the stiffness and drooling caused by my Parkinson’s disease. The downside was the noticeable dry mouth and occasional ‘fogginess,’ which my neurologist managed by adjusting the timing of my doses.” — Patient with Idiopathic Parkinson’s Disease.