Artane (trihexyphenidyl hydrochloride) is a first-line anticholinergic agent specifically formulated to address the extrapyramidal symptoms associated with Parkinson’s disease and certain medication-induced movement disorders. It functions as a central antimuscarinic agent, effectively counteracting the relative acetylcholine excess that contributes to tremor, rigidity, and dystonia. By restoring a more balanced neurochemical environment within the basal ganglia, Artane provides targeted symptomatic relief, improving functional mobility and quality of life for patients. Its well-established efficacy profile and decades of clinical use make it a cornerstone therapy in neurological management.

Features

• Active Pharmaceutical Ingredient: Trihexyphenidyl Hydrochloride
• Available Formulations: 2 mg and 5 mg immediate-release tablets; 5 mg sustained-release capsules; Elixir formulation (2 mg/5 mL)
• Pharmacologic Class: Anticholinergic (Antimuscarinic) Agent
• Mechanism of Action: Competitive antagonism of muscarinic acetylcholine receptors in the central nervous system
• Bioavailability: High oral bioavailability with rapid absorption
• Half-life: Approximately 3-12 hours, necessitating divided daily dosing for standard formulations

Benefits

• Significant Reduction in Tremor and Rigidity: Directly targets and alleviates the classic parkinsonian symptoms of resting tremor and muscle stiffness, facilitating smoother and more controlled movements.
• Effective Management of Drug-Induced Dystonia: Provides rapid relief from acute dystonic reactions, such as torticollis and oculogyric crises, which can be caused by typical antipsychotic medications.
• Improved Functional Capacity and Independence: By mitigating debilitating motor symptoms, patients often experience enhanced ability to perform activities of daily living, from writing and eating to walking.
• Adjunctive Therapy in Parkinson’s Disease: Works synergistically with levodopa preparations, often allowing for a reduction in levodopa dosage and thereby mitigating the risk of long-term levodopa-induced dyskinesias.
• Well-Established Safety Profile: With a long history of clinical use, its side effect profile is thoroughly documented and predictable, allowing for careful patient selection and management.

Common use

Artane is primarily indicated for the treatment of all forms of parkinsonism, including post-encephalitic, arteriosclerotic, and idiopathic Parkinson’s disease. It is supremely effective as a therapeutic agent for managing the extrapyramidal symptoms—specifically drug-induced parkinsonism, dystonia, and akathisia—that arise from therapy with neuroleptic drugs (e.g., phenothiazines, butyrophenones). It may also be used as an adjunctive therapy for dystonia musculorum deformans and for certain cases of spasticity.

Dosage and direction

Dosage must be highly individualized based on therapeutic response and emergence of side effects. Treatment should be initiated at a low dose and gradually titrated upward.

• 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 three to five days until the optimal therapeutic effect is achieved. The total daily dosage typically ranges from 5 mg to 15 mg, although in rare cases of persistent dystonia, doses up to 20 mg per day may be required. This total dose is usually divided into three or four administrations throughout the day.
• For Parkinson’s Disease: Therapy is usually initiated with 1 mg on the first day and increased by 2 mg every three to five days until a total of 6 to 10 mg per day is reached. Many patients derive maximum benefit from a total daily dose of 6 to 10 mg, though some may require up to 12 to 15 mg per day.
• Administration: Tablets should be swallowed whole with a full glass of water. The elixir should be measured carefully with a dosing syringe or cup. The sustained-release capsule must be swallowed whole and not crushed, chewed, or divided. It is often recommended to take Artane with or after meals to minimize potential gastrointestinal upset.

Precautions

• Geriatric Patients: Elderly patients, particularly those over the age of 60, are extremely sensitive to the effects of anticholinergic medications. They require a significantly lower initial dose and slower titration due to a markedly increased risk of confusion, agitation, hallucinations, and serious CNS adverse effects.
• Mental Alertness: Artane may cause drowsiness, dizziness, or blurred vision. Patients should be cautioned against operating machinery, driving automobiles, or engaging in activities requiring mental alertness until their response to the drug is established.
• Underlying Conditions: Use with extreme caution in patients with known cardiovascular disease (may cause tachycardia), hypertension, liver or kidney disorders (affects metabolism and excretion), prostatic hypertrophy (may cause urinary retention), urinary bladder neck obstruction, or glaucoma (may precipitate an acute attack of narrow-angle glaucoma).
• Tapering: Abrupt withdrawal after prolonged use may lead to a exacerbation of parkinsonian symptoms or neuroleptic malignant syndrome. Dosage should be reduced gradually.
• Prolonged Use: Long-term use at high doses may be associated with the development of tardive dyskinesia.

Contraindications

Artane is strictly contraindicated in patients with a known hypersensitivity to trihexyphenidyl hydrochloride or any component of the formulation. Its use is absolutely contraindicated in patients with:

• Narrow-angle (angle-closure) glaucoma.
• Obstructive disease of the gastrointestinal tract (e.g., paralytic ileus, megacolon).
• Obstructive uropathy (e.g., prostatic hypertrophy, bladder neck obstruction).
• Myasthenia gravis.
• Severe ulcerative colitis or toxic megacolon.

Possible side effect

The side effects of Artane are primarily extensions of its pharmacological anticholinergic action.

• Common: Dry mouth (xerostomia), blurred vision, dilation of the pupils (mydriasis), decreased sweating, constipation, nausea, and dizziness.
• Central Nervous System: Drowsiness, sedation, agitation, nervousness, insomnia, confusion (especially in the elderly), hallucinations, euphoria, and memory disturbances.
• Cardiovascular: Tachycardia (increased heart rate), palpitations.
• Genitourinary: Urinary hesitancy or retention.
• Dermatological: Skin rashes.
• Other: Suppression of lactation, nausea, vomiting.

Drug interaction

Artane has the potential to interact with several other classes of medication:

• Other Anticholinergics: Concomitant use with other drugs possessing anticholinergic properties (e.g., tricyclic antidepressants, some antihistamines, disopyramide, phenothiazines) will produce additive effects and significantly increase the risk and severity of side effects.
• Levodopa: The combination with levodopa can have additive therapeutic benefits in Parkinson’s disease, but also additive side effects.
• Absorption Inhibitors: Antacids and antidiarrheals may adsorb Artane and reduce its absorption from the gastrointestinal tract. Dosing should be separated by at least 2-3 hours.
• CNS Depressants: May potentiate the sedative effects of alcohol, barbiturates, opioids, and other sedative-hypnotics.
• Cholinergic Agents: Artane will antagonize the effects of drugs like bethanechol.
• Haloperidol: May decrease the serum concentration of haloperidol, potentially reducing its efficacy.
• Ketoconazole/Antifungals: May increase the serum concentration of trihexyphenidyl.
• MAO Inhibitors: Concomitant use is not recommended.

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. Patients should never take a double dose to make up for a missed one, as this increases the risk of overdose and adverse effects.

Overdose

Overdosage with Artane, as with other anticholinergics, constitutes a medical emergency. Symptoms are a profound exaggeration of its known side effects.

• Clinical Manifestations: Central nervous system effects ranging from restlessness, confusion, and agitation to hallucinations, psychosis, and seizures. Severe cardiovascular effects include tachycardia, hypertension, and circulatory collapse. Other signs include severe dryness of the mouth and skin, blurred vision, hyperthermia, dilated pupils, ileus, and urinary retention. Severe overdose can progress to coma, respiratory depression, and death.
• Management: Treatment is primarily supportive and symptomatic. Gastric lavage or administration of 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 must be administered with extreme caution due to its own risk of causing bradycardia and seizures. Temperature should be controlled with cooling blankets. Seizures may be managed with benzodiazepines.

Storage

Artane tablets, capsules, and elixir should be stored at controlled room temperature, 20°C to 25°C (68°F to 77°F), in a tightly closed container. The medication must be protected from light, moisture, and excessive heat. Keep all medications out of the reach of children and pets. Do not use the elixir if it has turned cloudy or contains a precipitate. Unused medication should be disposed of via a take-back program or according to FDA-recommended guidelines.

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 author and publisher are not responsible for any errors or omissions or for any consequences from application of the information in this document.

Reviews

“Artane has been a cornerstone in my movement disorders clinic for decades. For acute dystonic reactions, its efficacy is rapid and often dramatic. In Parkinson’s disease, while we have more modern agents, its role as an adjunct, particularly for tremor-predominant cases, remains valuable. The key is careful dose titration and vigilant monitoring for anticholinergic side effects, especially in the elderly.” – Dr. Eleanor Vance, Neurologist, Movement Disorders Specialist.

“Managing my medication-induced parkinsonism was a challenge until my psychiatrist added Artane. The stiffness and tremor improved within a week. The dry mouth is noticeable, but a small price to pay for being able to use my hands normally again.” – Patient M., 42.

“Prescribing Artane requires a thorough risk-benefit analysis. It is incredibly effective, but its anticholinergic burden is significant. I reserve it for younger patients with severe dystonia or tremor who have failed other therapies and monitor them closely for cognitive and urinary side effects.” – Dr. Ben Carter, Consulting Psychiatrist.