Duvoid

[doo´void] trademark for preparations of bethanechol chloride, a smooth relaxant" >muscle relaxant used to treat urinary retention.

bethanechol chloride

Duvoid (CA), Myotonachol (CA), Myotonine (UK), PMS-Bethanecol Chloride (CA), Urecholine

Pharmacologic class: Cholinergic

Therapeutic class: Urinary and GI tract stimulant

Pregnancy risk category C

Action

Stimulates parasympathetic nervous system and cholinergic receptors, leading to increased muscle tone in bladder and increased frequency of ureteral peristaltic waves. Also stimulates gastric motility, increases gastric tone, and restores rhythmic GI peristalsis.

Availability

Tablets: 5 mg, 10 mg, 25 mg, 50 mg

Indications and dosages

➣ Postpartal and postoperative non-obstructive urinary retention; urinary retention caused by neurogenic bladder

Adults: 10 to 50 mg P.O. three to four times daily; dosage may be determined by giving 5 or 10 mg q hour until response occurs or a total of 50 mg has been given.

Contraindications

• Hypersensitivity to drug

• GI or GU tract obstruction

• Hyperthyroidism

• Active or latent asthma

• Bradycardia

• Hypotension

• Atrioventricular conduction defects

• Coronary artery disease

• Seizure disorders

• Parkinsonism

• Peptic ulcer disease

Precautions

Use cautiously in:

• sensitivity to cholinergics or their effects and tartrazine (some products)

• pregnant or breastfeeding patients

• children.

Administration

• Give drug on empty stomach 1 hour before or 2 hours after a meal to help prevent nausea and vomiting.

Adverse reactions

CNS: headache, malaise, seizures

CV: bradycardia, hypotension, heart block, syncope with cardiac arrest

EENT: excessive lacrimation, miosis

GI: nausea, vomiting, diarrhea, abdominal discomfort, belching

GU: urinary urgency

Respiratory: increased bronchial secretions, bronchospasm

Skin: diaphoresis, flushing

Other: hypothermia

Interactions

Drug-drug. Anticholinergics: decreased bethanechol efficacy

Cholinesterase inhibitors: additive cholinergic effects

Depolarizing neuromuscular blockers: decreased blood pressure

Ganglionic blockers: severe hypotension

Procainamide, quinidine: antagonism of cholinergic effects

Drug-herbs. Angel's trumpet, jimson-weed, scopolia: antagonism of cholinergic effects

Patient monitoring

• Monitor blood pressure. Be aware that hypertensive patients may experience sudden blood pressure drop.

• Stay alert for orthostatic hypotension, a common adverse effect.

• Monitor fluid intake and output and residual urine volume.

Patient teaching

• Tell patient that drug is usually effective within 90 minutes of administration.

• Advise patient to take drug on empty stomach 1 hour before or 2 hours after a meal to avoid GI upset.

• Instruct patient to move slowly when sitting up or standing, to avoid dizziness or light-headedness from blood pressure decrease.

• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs, tests, and herbs mentioned above.

bethanechol

(be-than-e-kole) bethanechol,

Duvoid

(trade name),

Urabeth

(trade name),

Urecholine

(trade name)

Classification

Therapeutic: urinary tract stimulant
Pharmacologic: cholinergics
Pregnancy Category: C

Indications

Postpartum and postoperative nonobstructive urinary retention or urinary retention caused by neurogenic bladder.

Action

Stimulates cholinergic receptors. Effects include:

Contraction of the urinary bladder,

Decreased bladder capacity,

Increased frequency of ureteral peristaltic waves,

Increased tone and peristalsis in the GI tract,

Increased pressure in the lower esophageal sphincter,

Increased gastric secretions.

Therapeutic effects

Bladder emptying.

Pharmacokinetics

Absorption: Poorly absorbed after oral administration, requiring larger doses by mouth than subcutaneously.Distribution: Does not cross the blood-brain barrier.Metabolism and Excretion: Unknown.Half-life: Unknown.

Time/action profile (response on bladder muscle)

ROUTE	ONSET	PEAK	DURATION
PO	30–90 min	1 hr	6 hr
Subcut	5–15 min	15–30 min	2 hr

Contraindications/Precautions

Contraindicated in: Hypersensitivity; Mechanical obstruction of the GI or GU tract.Use Cautiously in: History of asthma; Ulcer disease; Cardiovascular disease; Epilepsy; Hyperthyroidism; Sensitivity to cholinergic agents or effects; Obstetric / Lactation / Pediatric: Safety not established.

Adverse Reactions/Side Effects

Central nervous system

headache
malaise

Ear, Eye, Nose, Throat

lacrimation
miosis

Respiratory

bronchospasm

Cardiovascular

heart block (life-threatening)
syncope/cardiac arrest (life-threatening)
bradycardia
hypotension

Gastrointestinal

abdominal discomfort (most frequent)
diarrhea (most frequent)
nausea (most frequent)
salivation (most frequent)
vomiting (most frequent)

Genitourinary

urgency (most frequent)

Miscellaneous

flushing (most frequent)
sweating (most frequent)
hypothermia

Interactions

Drug-Drug interaction

Quinidine and procainamide may antagonize cholinergic effects.Additive cholinergic effects with cholinesterase inhibitors.Use with ganglionic blocking agents may result in severe hypotension.Do not use with depolarizing neuromuscular blocking agents.Effectiveness will be decreased by anticholinergics.Cholinergic effects may be antagonized by angel's trumpet, jimson weed, or scopolia.

Route/Dosage

Oral (Adults) 25–50 mg 3 times daily. Dose may be determined by administering 5–10 mg q 1–2 hr until response is obtained or total of 50 mg administered or by starting with 10 mg, giving 25 mg 6 hr later, then, if needed, 50 mg 6 hr later.Oral (Children) 0.2 mg/kg 3 times daily or 0.15 mg/kg 4 times daily.Subcutaneous (Adults) 5 mg 3–4 times daily. Dose may be determined by administering 2.5 mg q 15–30 min until response is obtained or total of 4 doses administered.Subcutaneous (Children) 0.06 mg/kg 3 times daily or 0.05 mg/kg 4 times daily.

Availability (generic available)

Tablets: 5 mg, 10 mg, 25 mg, 50 mg Injection: 5 mg/mL

Nursing implications

Nursing assessment

Monitor BP, pulse, and respirations before administering and for at least 1 hr after subcut administration.
Monitor intake and output ratios. Palpate abdomen for bladder distention. Notify physician or other health care professional if drug fails to relieve condition for which it was prescribed. Catheterization may be ordered to assess postvoid residual.
Lab Test Considerations: May cause an increase in serum AST, amylase, and lipase concentrations.

Potential Nursing Diagnoses

Impaired urinary elimination (Indications)

Implementation

A test dose is usually employed before maintenance to determine minimum effective dose.
- Oral and subcut doses are not interchangeable.
Oral: Administer medication on an empty stomach, 1 hr before or 2 hr after meals, to prevent nausea and vomiting.
Subcutaneous: Parenteral solution is intended only for subcut administration. Do not give IM or IV. Inadvertent IM or IV administration may cause cholinergic overstimulation (circulatory collapse, drop in BP, abdominal cramps, bloody diarrhea, shock, and cardiac arrest).
- Do not use if solution is discolored or contains a precipitate.

Patient/Family Teaching

Instruct patient to take medication exactly as directed. Missed doses should be taken as soon as possible within 2 hr; otherwise, return to regular dosing schedule. Do not double doses.
Caution patient to change positions slowly to minimize orthostatic hypotension.
Advise patient to report abdominal discomfort, salivation, sweating, or flushing to health care professional.

Evaluation/Desired Outcomes

Increase in bladder function and tone.