oxybutynin chloride

oxybutynin chloride

(ox i byoo' ti nin)

Apo-Oxybutynin (CAN), Ditropan, Ditropan XL, Novo-Oxybutynin (CAN), Oxytrol

Pregnancy Category B

Drug classes

Anticholinergic

Urinary antispasmodic

Therapeutic actions

Acts directly to relax smooth muscle and inhibits the effects of acetylcholine at muscarinic receptors; reported to be less potent an anticholinergic than atropine but more potent as antispasmodic and devoid of antinicotinic activity at skeletal neuromuscular junctions or autonomic ganglia.

Indications

·        Relief of symptoms of bladder instability associated with voiding in patients with uninhibited neurogenic and reflex neurogenic bladder

·        ER tablets: Treatment of signs and symptoms of overactive bladder (incontinence, urgency, frequency); treatment of pediatric patients > 6 yr with symptoms of detrusor overactivity associated with a neurological condition (eg spina bifida) (Ditropan XL)

Contraindications and cautions

·        Contraindicated with allergy to oxybutynin, pyloric or duodenal obstruction, obstructive intestinal lesions or ileus, intestinal atony, megacolon, colitis, obstructive uropathies, glaucoma, myasthenia gravis, CV instability in acute hemorrhage, urinary retention.

·        Use cautiously with hepatic, renal impairment; pregnancy; lactation.

Available forms

Tablets—5 mg; syrup—5 mg/5 mL; ER tablets—5, 10, 15 mg; transdermal patch—3.9 mg/day

Dosages

ADULTS

5 mg PO bid or tid. Maximum dose is 5 mg qid. ER tablets—5 mg PO daily, up to a maximum of 30 mg/day; transdermal patch—one patch per day applied to dry, intact skin on the abdomen, hip, or buttock every 3–4 days.

PEDIATRIC PATIENTS > 5 YR

5 mg PO bid. Maximum dose is 5 mg tid.

Pharmacokinetics

Route	Onset	Peak	Duration
Oral	30–60 min	3–6 hr	6–10 hr
Transdermal	24–48 hr	Varies	96 hr

Metabolism: Hepatic; T_1/2: Unknown

Distribution: Crosses placenta; may enter breast milk

Excretion: Urine

Adverse effects

·        CNS: Drowsiness, dizziness, blurred vision, dilatation of the pupil, cycloplegia, increased ocular tension, weakness

·        CV: Tachycardia, palpitations

·        GI: Dry mouth, nausea, vomiting, constipation, bloated feeling

·        GU: Urinary hesitancy, retention, impotence

·        Hypersensitivity: Allergic reactions including urticaria, dermal effect

·        Other: Decreased sweating, heat prostration in high environmental temperatures secondary to loss of sweating

Interactions

Drug-drug

·        Decreased effectiveness of phenothiazines with oxybutynin

·        Decreased effectiveness of haloperidol and development of tardive dyskinesia

·        Increased toxicity if combined with amantadine, nitrofurantoin

Nursing considerations

Assessment

·        History: Allergy to oxybutynin, intestinal obstructions or lesions, intestinal atony, obstructive uropathies, glaucoma, myasthenia gravis, CV instability in acute hemorrhage, hepatic or renal impairment, pregnancy, lactation

·        Physical: Skin color, lesions; T; orientation, affect, reflexes; ophthalmologic examination, ocular pressure measurement; P, rhythm, BP; bowel sounds, liver evaluation; LFTs, renal function tests, cystometry

Interventions

·        Arrange for cystometry and other diagnostic tests before and during treatment.

·        Arrange for ophthalmologic examination before therapy and periodically during therapy.

Teaching points

·        Take this drug as prescribed.

·        If using the transdermal patch, apply to dry, intact skin on the abdomen, hip, or buttock every 3–4 days (twice weekly). Remove the old system before applying a new one. Select a new site for application of each new system.

·        Periodic bladder examinations will be needed during this treatment to evaluate therapeutic response.

·        You may experience these side effects: Dry mouth (suck sugarless lozenges and use frequent mouth care); GI upset; blurred vision; drowsiness (avoid driving or performing tasks that require alertness); decreased sweating (avoid high temperatures; serious complications can occur because you will be heat intolerant).

·        Report blurred vision, fever, rash, nausea, vomiting.

Adverse effects in Italic are more common; those in Bold are life-threatening.