Anticholinergics

Name of the Anticholinergics Drugs

• atropine
• benztropine
• glycopyrrolate
• scopolamine
• trihexyphenidyl
• diphenhydramine
• clinidium
• flavoxate
• oxybutynin
• orphenadrine

1.Atropine

Mechanism of Action

Inhibits acetylcholine’s muscarinic action at the neuroeffector junctions of smooth muscles, cardiac muscles, exocrine glands, SA and AV nodes, and the urinary bladder. In small doses, atropine inhibits salivary and bronchial secretions and diaphoresis. In moderate doses, it increases impulse conduction through the AV node and increases heart rate. In large doses, it decreases GI and urinary tract motility and gastric acid secretion.

Pharmacokinetics

• Half-life: 2-3 hr (>2 years and adults); 7 hr (<2 years); 10 hr (65-75 years)
• Peak plasma time: 3 min (IM)
• Onset: Rapid (IV/IM)
• Bronchodilation: Within 15 min; max within 15 min-1.5 hr (oral inhalation)
• Distribution: Throughout the body; crosses blood brain barrier
• Absorption: Principally from the upper small intestine
• Metabolites: Tropic acid, tropine, and possibly esters of tropic acid and glucuronide conjugates
• Metabolism: Liver via enzymatic hydrolysis
• Excretion: Urine (30-50%); small amounts may also be eliminated in expired air as carbon dioxide and in feces

Contraindications

Angle-closure glaucoma, asthma, GI obstructive disease (achalasia, pyloric obstruction, pyloroduodenal stenosis), hepatic disease, hypersensitivity to atropine or its components, ileus, intestinal atony, myasthenia gravis, myocardial ischemia, obstructive uropathy, renal disease, severe ulcerative colitis, tachycardia, toxic megacolon, unstable cardiovascular status in acute haemorrhage

Adverse Reactions

• CNS: Agitation, amnesia, anxiety, ataxia, Babinski’s or Chaddock’s reflex, behavioral changes, CNS stimulation (at high doses), coma, confusion, decreased concentration, decreased tendon reflexes, delirium, dizziness, drowsiness, fever, hallucinations, headache, hyperreflexia, insomnia, lethargy, mania, mental disorders, nervousness, paranoia, restlessness, seizures, somnolence, stupor, syncope, vertigo, weakness
• CV: Arrhythmias, bradycardia (at low doses), cardiac dilation, chest pain, hypertension, hypotension, left ventricular failure, MI, palpitations, tachycardia (at high doses), weak or impalpable peripheral pulses
• EENT: Acute angle-closure glaucoma, altered taste, blepharitis, blindness, blurred vision, conjunctivitis, cyclophoria, cycloplegia, decreased visual acuity or accommodation, dry eyes or conjunctiva, dry mucous membranes, dry mouth, eye irritation, eyelid crusting, heterophoria, increased intraocular pressure, keratoconjunctivitis, lacrimation, laryngitis, laryngospasm, mydriasis, nasal congestion, oral lesions, photophobia, pupils poorly reactive to light, strabismus, tongue chewing
• GI: Abdominal distention, abdominal pain, bloating, constipation, decreased bowel sounds or food absorption, delayed gastric emptying, dysphagia, heartburn, ileus, nausea, vomiting
• GU: Bladder distention, enuresis, impotence, urinary hesitancy, urinary urgency, urine retention
• MS: Dysarthria, hypertonia, muscle twitching
• RESP: Bradypnea, dyspnea, inspiratory stridor, pulmonary edema, respiratory failure, shallow breathing, subcostal recession, tachypnea
• SKIN: Cold skin, cyanosis, decreased sweating, dermatitis, flushing, rash, urticaria
• Other: Anaphylaxis, dehydration, injection site reaction, polydipsia, sensations of warmth

Nursing Considerations

• Avoid using high-dose atropine sulfate in patients with ulcerative colitis because of risk of toxic megacolon or in patients with hiatal hernia and reflux esophagitis because of risk of esophagitis
• AtroPen has no absolute contraindications when used to treat life-threatening nerve gas or insecticide exposure
• Assess bowel and bladder elimination. Notify prescriber of diarrhea, constipation, urinary hesitancy, or urine retention.

Patient Teaching

• For patient prescribed an AtroPen to carry because of risk of nerve gas or insecticide exposure, explain when and how to selfadminister the drug.
• Instruct patient to take atropine sulfate 30 to 60 minutes before meals.
• Advise patient to notify prescriber if he has persistent or severe diarrhea, constipation, or difficulty urinating

2.Benztropine

Mechanism of Action

Exerts anticholinergic and antihistaminic effects; may prolong action of dopamine by inhibiting its reuptake and storage

Pharmacokinetics

• Bioavailability: 29%
• Onset: PO, 1 hr; parenteral, 15 min
• Duration: 6-48 hr
• Protein bound: 95%
• Trace amounts found unchanged in feces

Administration

• Give after meals to prevent GI upset.
• Crush tablets if patient has difficulty swallowing them.
• Know that I.V. route is seldom used.
• Be aware that entire dose may be given at bedtime. (Drug has long duration of action.)

Contraindications

• Hypersensitivity to drug
• Angle-closure glaucoma
• Tardive dyskinesia
• Children younger than age 3

Precautions :

• Seizure disorders, arrhythmias, tachycardia, hypertension, hypotension, hepatic or renal dysfunction, alcoholism, prostatic hypertrophy
• Elderly patients
• Pregnant or breastfeeding patients.

Adverse reactions

• CNS: confusion, depression, dizziness, hallucinations, headache, weakness, memory impairment, nervousness, delusions, euphoria, paresthesia, sensation of heaviness in limbs,toxic psychosis
• CV: hypotension, palpitations, tachycardia, arrhythmias
• EENT: blurred vision, diplopia, mydriasis, angle-closure glaucoma
• GI: nausea, constipation, dry mouth, ileus
• GU: urinary hesitancy or retention, dysuria, difficulty maintaining erection
• Musculoskeletal: paratonia, muscle weakness and cramps
• Skin: rash, urticaria, decreased sweating, dermatoses

Patient monitoring

• Monitor blood pressure closely, especially in elderly patients.
• Monitor fluid intake and output; check for urinary retention.
•   Assess for signs and symptoms of ileus, including constipation and abdominal distention

Patient teaching

• Advise patient to use caution during activities that require physical or mental alertness, because drug causes sedation.
• Tell patient to avoid increased heat exposure.
• Caution patient not to stop therapy abruptly.
• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs, herbs, and behaviors mentioned above.

3.Glycopyrrolate

Mechanism of Action

Competitively inhibits action of ACh on autonomic effectors innervated by postganglionic nerves

Inhibits salivation, tracheobronchial secretions, bradycardia, and hypotension

Pharmacokinetics

• Peak plasma time: 30-45 min
• Incompletely absorbed from GI tract since completely ionized
• Several metabolites
• Excretion: Mainly as unchanged drug in feces via biliary elimination and in urine

Administration

• Give oral dose 30 to 60 minutes before meals.
• For I.V. injection, give either undiluted or diluted with dextrose 5% or 10% in water or saline solution. Give each 0.2 mg over 1 to 2 minutes.
• Keep resuscitation equipment on hand to treat curare-like effects of overdose.

Contraindications

• Hypersensitivity to drug
• Arrhythmias
• Chronic obstructive pulmonary disease
• GI disease, infection, atony or ileus
• Myasthenia gravis
• Glaucoma
• Obstructive uropathy
• Severe prostatic hypertrophy

Precautions :

• Cardiovascular disease, heart failure, hypertension, renal or hepatic disease, Down syndrome, hyperthyroidism, hiatal hernia, ulcerative colitis, mild to moderate prostatic hypertrophy, autonomic neuropathy, spasticity, suspected brain damage
• Pregnant or breastfeeding patients

Adverse reactions

• CNS: weakness, nervousness, insomnia, drowsiness, dizziness, headache, confusion, excitement
• CV: palpitations, tachycardia
• EENT: blurred vision, photophobia, mydriasis, increased intraocular pressure, cycloplegia
• GI: nausea, vomiting, constipation, abdominal distention, epigastric distress, heartburn, gastroesophageal reflux, dry mouth, paralytic ileus
• GU: urinary hesitancy or retention, lactation suppression, erectile dysfunction
• Skin: urticaria, decreased sweating or anhidrosis
• Other: loss of taste, fever, allergic reaction, irritation at I.M. injection site, anaphylaxis, malignant hyperthermia

Patient monitoring

• Check for signs and symptoms of anaphylaxis and malignant hyperthermia.
• Monitor neurologic and cardiovascular status.
• Assess for curare-like effects (neuromuscular blockade leading to muscle weakness and possible paralysis), which indicate overdose.
• Assess fluid intake and output. Have patient void before each dose to avoid urinary retention

Patient teaching

• Advise patient to take oral dose 30 to 60 minutes before meals.
• Tell patient to immediately report signs and symptoms of serious adverse effects, especially anaphylaxis.
• Caution patient to avoid driving and other hazardous activities until he knows how drug affects concentration, vision, and alertness.
• Tell patient to minimize GI upset by eating frequent, small servings of food and drinking adequate fluids.
• Advise patient to report urinary hesitancy or retention.
• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs mentioned above.

4.Scopolamine

Mechanism of Action

Anticholinergic belladonna alkaloid

Generally, exhibits pharmacologic actions associated with other antimuscarinics

May prevent motion-induced nausea and vomiting by blocking transmission of cholinergic impulse from vestibular nuclei to higher centers in CNS and from reticular formation to vomiting center

Pharmacokinetics

• Peak plasma time: 24 hr (transdermal)
• Metabolized by liver (via conjugation)
• Half-life: 9.5 hr
• Excretion: Primarily urine (90% as metabolites)

Administration

• For I.V. use, given by direct injection at prescribed rate after diluting with sterile water.
• After removing protective strip from transdermal patch, avoid finger contact with exposed adhesive layer to prevent contamination.

Contraindications

• Hypersensitivity to scopolamine, other belladonna alkaloids, or barbiturates
• Hypersensitivity to bromides (injection only)
• Angle-closure glaucoma
• Acute hemorrhage
• Myasthenia gravis
• Obstructive uropathy (including prostatic hypertrophy)
• Obstructive GI disease (including paralytic ileus and intestinal atony)
• Reflux esophagitis
• Ulcerative colitis or toxic megacolon
• Hepatic or renal impairment
• Chronic lung disease (with repeated doses)

Precautions :

• Suspected intestinal obstruction; pulmonary or cardiac disease; tachyarrhythmia or tachycardia; openangle glaucoma; autonomic neuropathy; hypertension; hyperthyroidism; ileostomy or colostomy
• History of seizures or psychosis
• Elderly patients
• Pregnant or breastfeeding patients (safety not established)
• Children.

Adverse reactions

• CNS: drowsiness, dizziness, confusion, restlessness, fatigue
• CV: tachycardia, palpitations, hypotension, transient heart rate changes
• EENT: blurred vision, mydriasis, photophobia, conjunctivitis
• GI: constipation, dry mouth
• GU: urinary hesitancy or retention Skin: decreased sweating, rash

Patient monitoring

• Assess vital signs and neurologic, cardiovascular, and respiratory status.
• Monitor patient for urinary hesitancy or retention.

Patient teaching

• Tell patient transdermal patch is most effective if applied to dry skin behind ear 4 hours before traveling.
• Caution patient to avoid touching exposed adhesive layer of transdermal patch.
• Advise patient to wash and dry hands thoroughly before and after applying patch.
• If patch becomes dislodged, instruct patient to remove it and apply new patch on a different site behind ear.
• Tell patient that using patch for more than 72 hours may cause withdrawal symptoms (headache, nausea, vomiting, dizziness). Advise him to limit use when feasible.
• Inform patient that his eyes may be markedly sensitive to light during patch use. Instruct him to wear sunglasses and use other measures to guard eyes from light.
• Caution patient to avoid alcohol because it may increase CNS depression.
• As appropriate, review all other significant adverse reactions and interactions, especially those related to the drugs, herbs, and behaviors mentioned above.

5.Trihexyphenidyl

Mechanism of Action

Trihexyphenidyl inhibits the parasympathetic nervous system and has a relaxing effect on smooth muscles

Pharmacokinetics

• Half-Life elimination: 33 hr
• Onset: 1 hr
• Peak effects: 1.3 hr
• Duration: 6-12 hr
• Metabolism: Unknown
• Excretion: Urine and bile

Administration

• Give with meals. However, if drug causes severe dry mouth, give before meals.
• Administer last dose at bedtime.

Contraindications

• Hypersensitivity to drug or its components
• Angle-closure glaucoma
• Pyloric or duodenal obstruction
• Stenosing peptic ulcer
• Megacolon
• Prostatic hypertrophy or bladder neck obstruction
• Achalasia
• Myasthenia gravis

Precautions:

• Chronic renal, hepatic, pulmonary, or cardiac disease; hypertension; tachycardia secondary to cardiac insufficiency; hyperthyroidism
• Elderly patients
• Pregnant or breastfeeding patients
• Children (safety not established)

Adverse reactions

• CNS: dizziness, nervousness, drowsiness, asthenia, headache
• CV: orthostatic hypotension, tachycardia
• EENT: blurred vision, mydriasis, increased intraocular pressure (IOP), angle-closure glaucoma (with longterm use)
• GI: nausea, vomiting, constipation, dry mouth
• GU: urinary hesitancy or retention

Patient monitoring

• With prolonged use, monitor vision and IOP regularly.
• Assess drug efficacy to help guide dosage titration.
• Monitor vital signs. Watch for orthostatic hypotension.
• Closely monitor fluid intake and output. Stay alert for urinary retention.

Patient teaching

• Instruct patient to take with meals or, if severe dry mouth occurs, before meals.
• Tell patient drug has a bitter taste, which may be followed by numbness and tingling in mouth.
• Stress importance of follow-up eye exams.
• Instruct patient to consult prescriber before taking over-the-counter preparations or herbs.
• Advise patient to avoid alcohol and hazardous activities during drug therapy.
• Tell patient to move slowly when sitting up or standing, to avoid dizziness from sudden blood pressure decrease.
• As appropriate, review all other significant adverse reactions and interactions, especially those related to the drugs, herbs, and behaviors mentioned above

6.Diphenhydramine

Mechanism of Action

Histamine H1-receptor antagonist of effector cells in respiratory tract, blood vessels, and GI smooth muscle

Moderate to high anticholinergic and antiemetic properties

Pharmacokinetics

• Bioavailability: PO, 42-62% (drug is well absorbed but undergoes first-pass metabolism)
• Peak serum time: 2 hr (PO)
• Protein bound: 98.5%
• Metabolized by liver (first pass)
• Half-life: 5 hr (children); 9 hr (adults); 13.5 hr (elderly)
• Excretion: Urine (50-75%), mainly as metabolites

Administration

• For motion sickness, administer 30 minutes before activity.
• For I.V. use, check compatibility before mixing with other drugs.
• Inject I.M. dose deep into large muscle mass; rotate sites.
• Discontinue drug 4 days before allergy skin testing to avoid misleading results.
• Don’t give within 14 days of MAO inhibitors.

Contraindications

• Hypersensitivity to drug
• Alcohol intolerance
• Acute asthma attacks
• MAO inhibitor use within past 14 days
• Breastfeeding
• Neonates, premature infants

Precautions:

• Severe hepatic disease, angle-closure glaucoma, seizure disorders, prostatic hypertrophy, cardiovascular disease, hyperthyroidism
• Elderly patients
• Pregnant patients (safety not established)
• Children younger than age 2 (safety not established).

Adverse reactions

• CNS: drowsiness, dizziness, headache, paradoxical stimulation (especially in children)
• CV: hypotension, palpitations, tachycardia
• EENT: blurred vision, tinnitus
• GI: diarrhea, constipation, dry mouth
• GU: dysuria, urinary frequency or retention
• Skin: photosensitivity
• Other: decreased appetite, pain at I.M. injection site

Patient monitoring

• Monitor cardiovascular status, especially in patients with cardiovascular disease.
• Supervise patient during ambulation. Use side rails as necessary

Patient teaching

• Advise patient to avoid alcohol and other depressants such as sedatives while taking drug.
• Caution patient to avoid driving and other hazardous activities until he knows how drug affects concentration and alertness.
• As appropriate, review all other significant adverse reactions and interactions, especially those related to the drugs, tests, herbs, and behaviors mentioned above

7.Clinidium

Mechanism of Action

Inhibits acetylcholine’s muscarinic actions at postganglionic parasympathetic receptor sites, including smooth muscles, secretory glands, and the CNS. These actions relax smooth muscles and diminish GI, GU, and biliary tract secretions.

Pharmacokinetics

Half-Life: 6-24 h (chlordiazepoxide)

Metabolites: Metabolized in liver to active metabolites; demoxepam, desmethylchlordiazepoxide, desmethyldiazepam, oxazepam

Excretion: Urine

Contraindications

Angle-closure glaucoma, benign bladder neck obstruction, hypersensitivity to clidinium bromide or its components, ileus, intestinal atony (elderly or debilitated patients), intestinal obstruction, myasthenia gravis, myocardial ischemia, ocular adhesions between lens and iris, prostatic hypertrophy, renal disease, severe ulcerative colitis, tachycardia, toxic megacolon, unstable cardiovascular status in acute hemorrhage

Adverse Reactions

• CNS: Confusion, dizziness, drowsiness, excitement, fever, headache, insomnia, memory loss, nervousness, weakness CV: Palpitations, tachycardia
• EENT: Blurred vision, cycloplegia, dry mouth, increased intraocular pressure, loss of taste, mydriasis, nasal congestion, pharyngitis, photophobia
• GI: Bloating, constipation, dysphagia, heartburn, ileus, nausea, vomiting
• GU: Impotence, urinary hesitancy, urine retention
• SKIN: Decreased sweating, flushing, rash, urticaria

Nursing Considerations

• Avoid high doses in patients with ulcerative colitis because clindinium may inhibit intestinal motility and cause or worsen toxic megacolon. Also avoid high doses in patients with hiatal hernia or reflux esophagitis because drug may aggravate esophagitis.
• Use drug cautiously in patients with heart failure, arrhythmias, hypertension, autonomic neuropathy, hyperthyroidism, allergies, asthma, or debilitating chronic lung disease
• Take safety precautions to protect patient from injury from falling

Patient Teaching

• Instruct patient to take clidinium exactly as prescribed and not to stop taking it suddenly because it can cause withdrawal symptoms, such as vomiting, diaphoresis, and dizziness.
• Advise patient to take drug 30 to 60 minutes before meals.
• Tell patient not to store capsules in damp places, such as the bathroom.
• Teach patient how to prevent or relieve constipation and dry mouth.
• Instruct patient to avoid alcohol and other CNS depressants because they increase the drug’s effects. • Instruct patient to report constipation, vision changes, sore throat, difficulty urinating, and palpitations.

8.Flavoxate

Mechanism of Action

 Relaxes muscles by cholinergic blockade and counteracts smooth-muscle spasms in the urinary tract.

Pharmacokinetics

Onset: 55 min

Peak Effect: 112 min

Excretion: Urine (10-30%)

Contraindications

Achalasia; GI hemorrhage; hypersensitivity to flavoxate or its components; obstruction of the duodenum, ileum, or pylorus; obstructive uropathies of the lower urinary tract

Adverse Reactions

• CNS: Confusion, decreased concentration, dizziness, drowsiness, fever, headache, nervousness, vertigo
• CV: Palpitations, tachycardia
• EENT: Accommodation disturbances, blurred vision, dry mouth, eye pain, photophobia, worsening of glaucoma
• GI: Constipation, nausea, vomiting
• GU: Dysuria
• HEME: Eosinophilia, leukopenia
• SKIN: Decreased sweating, dermatoses, urticaria

Nursing Considerations

•   Monitor for eye pain if patient has glaucoma because flavoxate’s anticholinergic effects may worsen glaucoma.

 Patient Teaching

• Caution patient about possible dry mouth and photophobia. Advise her to wear sunglasses outdoors, and suggest sugarless candy or gum, ice chips, sips of water, or saliva substitute for dry mouth.
• Advise patient to avoid hazardous activities until CNS effects of flavoxate are known.
• Caution patient not to become overheated or to take hot baths or saunas during therapy because drug reduces sweating, which can lead to dizziness, fainting, or heatstroke.
• Instruct patient to notify prescriber immediately if she experiences confusion, drowsiness, dysuria, headache, high fever, hives, nausea, nervousness, palpitations, rash, tachycardia, vertigo, vision problems, vomiting, or worsening dry mouth.

9.Oxybutynin

Mechanism of Action

Exerts antimuscarinic (atropine-like) and potent direct antispasmodic (papaverine like) actions on smooth muscle in the bladder and decreases detrusor muscle contractions. The result is increased bladder capacity and a decreased urge to void.

Pharmacokinetics

Bioavailability: 6% (~1.5-2 times higher for extended-release)

Peak plasma time: <1 hr (immediate release); 12 hr (extended release)

Metabolized in liver and gut by CYP3A4; converted to active metabolite N-desethyloxybutynin (DEO) by GI metabolic pathways, which are bypassed in transdermal delivery, resulting in lower DEO ratio

Half-life: 2-3 hr (immediate-release); 12-13 hr (extended-release)

Excretion: Urine

Contraindications

Acute hemorrhage, angle-closure glaucoma, gastric retention (gel form), GI obstruction, hypersensitivity to oxybutynin or its components, ileus, intestinal atony in elderly or debilitated patients, myasthenia gravis, obstructive uropathy, toxic megacolon with ulcerative colitis, urine retention (gel form)

Adverse Reactions

• CNS: Agitation, asthenia, confusion, dizziness, drowsiness, fatigue, hallucinations, headache, insomnia, memory impairment, nervousness, psychosis, restlessness, seizures, somnolence
• CV: Arrhythmias, hypertension, hypotension, palpitations, peripheral edema, QT interval prolongation, tachycardia, vasodilation
• EENT: Blurred vision; cycloplegia; dry eyes, mouth, nose, and throat; keratoconjunctivitis sicca; eye irritation; mydriasis; nasopharyngitis; rhinitis; sinusitis
• ENDO: Hyperglycaemia, suppression of lactation GI: Abdominal pain, constipation, decreased GI motility, diarrhea, dysphagia, esophagitis, flatulence, gastroesophageal reflux, indigestion, nausea, vomiting
• GU: Cystitis, dysuria, impotence, urinary hesitancy, urine retention, UTI
• MS: Arthralgia, arthritis, back pain
• RESP: Asthma, bronchitis, cough, upper respiratory tract infection
• SKIN: Decreased sweating, dry skin, flushing, pruritus, rash, urticaria
• Other: Application site reactions (anesthesia, dermatitis, erythema, irritation, papules, pruritus), flulike symptoms, fungal infections, heatstroke

Nursing Considerations

• Use oxybutynin cautiously in patients with diarrhea because it may signal incomplete GI obstruction, especially in patients with colostomy or ileostomy. Also use cautiously in patients with dementia because drug may aggravate symptoms.
• Use cautiously in patients with myasthenia gravis or GI disorders because drug may adversely affect these conditions.
• Assess urinary symptoms before and after treatment.
• Make sure patient swallows E.R. tablets whole and doesn’t crush, chew, or divide them. Expect to see portions of drug in stool.
• Apply transdermal system to dry, intact skin of abdomen, hip, or buttock; avoid using same site for at least 7 days by rotating sites.
• Apply gel form to dry, intact skin on patient’s abdomen, upper arms, shoulders, or thighs. Rotate application sites.
• Decreased GI motility can cause adynamic ileus; assess for abdominal pain and ileus.
• Be aware that drug may aggravate benign prostatic hyperplasia, gastroesophageal reflux disease, and hyperthyroidism.
• Monitor patient for anticholinergic CNS effects, such as hallucinations, agitation, confusion and somnolence, especially in the first few months of therapy or when dosage is increased. If such effects occur, notify prescriber and expect dosage to be reduced or drug discontinued.

Patient Teaching

• Instruct patient to take oxybutynin on an empty stomach. If adverse GI reactions develop, suggest taking drug with food or milk.
• Advise patient to swallow tablets whole and not to chew, crush, or break them.
• Instruct patient how to apply transdermal system or gel. Tell her to apply to clean, dry skin, avoiding areas that have been recently shaved or have open sores or rashes. Remind patient to wash hands after handling product.
• Warn patient that gel is flammable and that she should avoid open fire or smoking until gel has dried. Also tell patient to avoid bathing, swimming, showering, exercising, or immersing application site in water for 1 hour after application and to cover site with clothing once gel has dried. • Warn of possible decreased alertness, and advise patient against performing hazardous activities until drug’s CNS effects are known.
• Caution patient to avoid strenuous exercise and excessive sun exposure because of increased risk of heatstroke.
• Urge patient to avoid alcohol during therapy.

10.Orphenadrine

Mechanism of Action

 May reduce muscle spasms by acting on cerebral motor centers or medulla. Postganglionic anticholinergic effects and some antihistaminic and local anesthetic action contribute to skeletal muscle relaxation

Pharmacokinetics

• Half-life elimination: 14-16 hr
• Onset: 2-4 hr (peak)
• Duration: 4-6 hr
• Metabolism: Liver
• Protein binding: 20%
• Metabolites: Not fully determined (>8 metabolites)
• Excretion: urine (principally)

Contraindications

Angle-closure glaucoma; hypersensitivity to orphenadrine or its components; myasthenia gravis; obstruction of bladder neck, duodenum, or pylorus; prostatic hypertrophy; stenosing peptic ulcers

Adverse Reactions

• CNS: Agitation, confusion, dizziness, drowsiness, light-headedness, syncope, tremor
• CV: Palpitations, tachycardia
• EENT: Blurred vision, dry eyes and mouth, increased contact lens awareness
• GI: Abdominal distention, constipation, nausea, vomiting
• GU: Urine retention

Nursing Considerations

• Be aware that orphenadrine shouldn’t be given to patients with tachycardia or cardiac insufficiency.
• Give I.V. form over 5 minutes with patient in supine position. Have patient stay in this position for 5 to 10 minutes to minimize adverse reactions. Then help him to sitting position.
• Be aware that drug can aggravate myasthenia gravis and cause tachycardia.
• Anticipate that drug’s anticholinergic effects may cause blurred vision, dry eyes, and increased contact lens awareness.

Patient Teaching

• Advise patient to avoid hazardous activities until drug’s CNS effects are known.
• Explain that dry mouth may occur, and suggest increased fluid intake, ice chips, and sugarless candy or gum.
• Suggest that patient (especially one who wears contact lenses) use artificial tears to avoid discomfort from dry eyes.

REFERENCES

1. Robert Kizior, Keith Hodgson, Saunders Nursing Drug handbook,1st edition 2024, Elsevier Publications. ISBN-9780443116070
2. McGraw Hill- Drug Handbook, Seventh Edition, 2013, McGraw Hill Education Publications,9780071799430.
3. April Hazard, Cynthia Sanoski, Davi’s Drug Guide for Nurses -Sixteenth Edition 2019, FA Davis Company Publications,9780803669451.
4. Jones and Bartlet, Pharmacology for Nurses, Second Edition, 2020, Jones and Bartlet Learning Publications, ISBN 9781284141986.
5. Nursebro.com, Search – Nursebro

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