No

Anticholinergic Agent; Anti-Parkinson's Agent (Anticholinergic)

Relieves symptoms of parkinsonian syndrome and drug-induced extrapyramidal symptoms

C

Angle-closure glaucoma; safe use in children not established

Use with caution in hot weather or during exercise. Elderly patients frequently develop increased sensitivity and require strict dosage regulation - side effects may be more severe in elderly patients with atherosclerotic changes. Use with caution in patients with tachycardia, cardiac arrhythmias, hypertension, hypotension, prostatic hypertrophy (especially in the elderly) or any tendency toward urinary retention, liver or kidney disorders and obstructive disease of the GI or GU tract. When given in large doses or to susceptible patients, may cause weakness and inability to move particular muscle groups.

Cardiovascular: Tachycardia, palpitations

Central nervous system: Confusion, drowsiness, headache, loss of memory, fatigue, ataxia, giddiness, lightheadedness

Dermatologic: Dry skin, increased sensitivity to light, rash

Gastrointestinal: Constipation, xerostomia, dry throat, nausea, vomiting, epigastric distress

Genitourinary: Difficult urination

Neuromuscular & skeletal: Weakness

Ocular: Increased intraocular pain, blurred vision, mydriasis

Respiratory: Dry nose

Miscellaneous: Diaphoresis (decreased)

Symptoms of overdose include disorientation, hallucinations, delusions, blurred vision, dysphagia, absent bowel sounds, hyperthermia, hypertension, urinary retention

Anticholinergic toxicity is caused by strong binding of the drug to cholinergic receptors. Anticholinesterase inhibitors reduce acetylcholinesterase, the enzyme that breaks down acetylcholine and thereby allows acetylcholine to accumulate and compete for receptor binding with the offending anticholinergic. For anticholinergic overdose with severe life-threatening symptoms, physostigmine 1-2 mg (0.5 mg or 0.02 mg/kg for children) S.C. or I.V., slowly may be given to reverse these effects.

Decreased effect: May increase gastric degradation of levodopa and decrease the amount of levodopa absorbed by delaying gastric emptying; the opposite may be true for digoxin

Therapeutic effects of cholinergic agents (tacrine, donepezil) and neuroleptics may be antagonized

Increased toxicity: Central and/or peripheral anticholinergic syndrome can occur when administered with amantadine, rimantadine, narcotic analgesics, phenothiazines and other antipsychotics (especially with high anticholinergic activity), tricyclic antidepressants, quinidine and some other antiarrhythmics, and antihistamines

Thought to act by blocking excess acetylcholine at cerebral synapses; many of its effects are due to its pharmacologic similarities with atropine; it exerts an antispasmodic effect on smooth muscle, is a potent mydriatic; inhibits salivation

Onset of effect: Oral: Within 30-40 minutes

Duration: 4-6 hours

Adults: Oral: 2.5 mg 3 times/day after meals; if tolerated, gradually increase dose, maximum of 20 mg/day if necessary

Alcohol: Avoid use

No information available to require special precautions

>10% of patients experience dry mouth; prolonged use of antidyskinetics may decrease or inhibit salivary flow and could contribute to development of periodontal disease, oral candidiasis or discomfort

Take exactly as directed (after meals); do not increase, decrease, or discontinue without consulting prescriber. Take at the same time each day. Do not use alcohol and all prescription or OTC sedatives or CNS depressants without consulting prescriber. You may experience drowsiness, dizziness, confusion, and blurred vision (use caution when driving, climbing stairs, or engaging in tasks requiring alertness until response to drug is known); increased susceptibility to heat stroke, decreased perspiration (use caution in hot weather - maintain adequate fluids and reduce exercise activity); constipation (increased exercise, fluids, or dietary fruit and fiber may help); dry skin or nasal passages (consult prescriber for appropriate relief). Report unresolved constipation, chest pain or palpitations, difficulty breathing, CNS changes (hallucination, loss of memory, nervousness, etc), painful or difficult urination, increased muscle spasticity or rigidity, skin rash, or significant worsening of condition. Pregnancy/breast-feeding precautions: Inform prescriber if you are or intend to be pregnant. Breast-feeding is not recommended.

Do not discontinue drug abruptly

Tablet, as hydrochloride: 5 mg

Feinberg M, "The Problems of Anticholinergic Adverse Effects in Older Patients," Drugs Aging, 1993, 3(4):335-48.