Yes

Anti-Parkinson's Agent (Anticholinergic); Skeletal Muscle Relaxant

Treatment of muscle spasm associated with acute painful musculoskeletal conditions; supportive therapy in tetanus

C

Glaucoma, GI obstruction, cardiospasm, myasthenia gravis, hypersensitivity to orphenadrine or any component

Use with caution in patients with CHF or cardiac arrhythmias; some products contain sulfites

>10%:

Central nervous system: Drowsiness, dizziness

Ocular: Blurred vision

1% to 10%:

Cardiovascular: Flushing of face, tachycardia, syncope

Dermatologic: Rash

Gastrointestinal: Nausea, vomiting, constipation

Genitourinary: Decreased urination

Neuromuscular & skeletal: Weakness

Ocular: Nystagmus, increased intraocular pressure

Respiratory: Nasal congestion

<1%: Hallucinations, aplastic anemia

Symptoms of overdose include blurred vision, tachycardia, confusion, seizures, respiratory arrest, dysrhythmias

There is no specific treatment for an antihistamine overdose, however, most of its clinical toxicity is due to anticholinergic effects. Anticholinesterase inhibitors may be useful by reducing acetylcholinesterase. Anticholinesterase inhibitors include physostigmine, neostigmine, pyridostigmine and edrophonium. For anticholinergic overdose with severe life-threatening symptoms, physostigmine 1-2 mg (0.5 mg or 0.02 mg/kg for children) I.V., slowly may be given to reverse these effects. Lethal dose is 2-3 g; treatment is symptomatic.

CYP2B6, 2D6, and 3A3/4 enzyme substrate; CYP2B6 enzyme inhibitor

Indirect skeletal muscle relaxant thought to work by central atropine-like effects; has some euphorigenic and analgesic properties

Peak effect: Oral: Within 2-4 hours

Duration: 4-6 hours

Protein binding: 20%

Metabolism: Extensive

Half-life: 14-16 hours

Elimination: Primarily in urine (8% as unchanged drug)

Adults:

I.M., I.V.: 60 mg every 12 hours

Alcohol: Additive CNS effect, avoid use

Drowsiness and dizziness are common; may rarely cause hallucinations

May rarely cause aplastic anemia; use caution with clozapine and carbamazepine; has been used to treat tardive dyskinesia and augment typical antipsychotics; clozapine is a better option; concurrent use with psychotropics may produce additive sedation

No information available to require special precautions

The peripheral anticholinergic effects of orphenadrine may decrease or inhibit salivary flow; normal salivation will return with cessation of drug therapy

Take exactly as directed. Do not increase dose or discontinue without consulting prescriber. Do not chew or crush sustained release tablets. Do not use alcohol, prescriptive or OTC antidepressants, sedatives, or pain medications without consulting prescriber. You may experience drowsiness, dizziness, lightheadedness (avoid driving or engaging in tasks requiring alertness until response to drug is known); nausea or vomiting (small, frequent meals, frequent mouth care, or sucking hard candy may help); constipation (increased dietary fluids and fibers or increased exercise may help); or decreased urination (void before taking medication). Report excessive drowsiness or mental agitation, chest pain, skin rash, swelling of mouth/face, difficulty speaking, or vision disturbances. Pregnancy/breast-feeding precautions: Inform prescriber if you are or intend to be pregnant. Consult prescriber if breast-feeding.

Do not crush sustained release drug product; raise bed rails, institute safety measures, assist with ambulation

Injection, as citrate: 30 mg/mL (2 mL, 10 mL)

Tablet, as citrate: 100 mg

Tablet, as citrate, sustained release: 100 mg

Beech M, Hell C, and Nightingale P, "Central Anticholinergic Syndrome," Lancet, 1987, 1(8541):1089.

Boyson SJ, "Bethanechol for Anticholinergic Side Effects," Ann Neurol, 1988, 23(4):422-3.

Clarke B, Mair J, and Rudolf M, "Acute Poisoning With Orphenadrine," Lancet, 1985, 1(8442):1386.

Danze LK and Langdorf MI, "Reversal of Orphenadrine-Induced Ventricular Tachycardia With Physostigmine," J Emerg Med, 1991, 9(6):453-7.