Drugs Flashcards
What is the mechanism of action of Bethanechol?
Binds reversibly to muscarinic cholinergic receptors and activates them.
What is the route of administration of Bethanechol and what is the onset and duration?
Oral
30-60 min onset
duration: 1 hour
What is the absorption of Bethanechol?
minimal systemic absorption
The nurse understands that the mechanism of action of Bethanechol is to:
A. Block muscarinic cholinergic receptors to decrease bladder tone
B. Bind reversibly to muscarinic cholinergic receptors and activate them
C. Inhibit the release of acetylcholine at muscarinic receptors
D. Increase norepinephrine release to stimulate urinary contraction
Answer: B. Bind reversibly to muscarinic cholinergic receptors and activate them
Rationale: Bethanechol is a muscarinic agonist that binds reversibly to muscarinic cholinergic receptors, activating them and thereby increasing smooth muscle tone, which is beneficial for treating urinary retention. It does not block receptors, inhibit acetylcholine release, or stimulate norepinephrine.
The nurse understands that Bethanechol promotes urination by causing which of the following effects on the bladder?
A. Contraction of the trigone and sphincter muscles
B. Relaxation of the detrusor muscle
C. Contraction of the detrusor muscle and relaxation of the trigone and sphincter
D. Relaxation of all bladder muscles
Answer: C. Contraction of the detrusor muscle and relaxation of the trigone and sphincter
Rationale: Bethanechol stimulates muscarinic receptors, resulting in detrusor muscle contraction (which increases bladder pressure) and relaxation of the trigone and sphincter muscles, allowing for urination. This combination facilitates urine flow.
A patient taking Bethanechol for urinary retention reports feeling an urgent need to urinate. The nurse recognizes that this effect is due to Bethanechol’s action on which part of the bladder?
A. Increased tone in the trigone
B. Contraction of the detrusor muscle
C. Relaxation of the detrusor muscle
D. Contraction of the internal sphincter
Answer: B. Contraction of the detrusor muscle
Rationale: Bethanechol’s activation of muscarinic receptors causes the detrusor muscle to contract, creating pressure within the bladder that leads to the sensation of urgency and facilitates urination. This is its intended action in treating urinary retention.
The nurse knows that Bethanechol may have effects on the eyes due to its action on muscarinic receptors. Which ocular effect should the nurse anticipate?
A. Dilation of pupils with blurred near vision
B. Constriction of pupils with enhanced near-focusing
C. Dilation of pupils and enhanced distance focusing
D. Constriction of pupils with blurred distance vision.
Answer: B. Constriction of pupils with enhanced near-focusing
Rationale: Bethanechol’s activation of muscarinic receptors in the eyes causes miosis (pupil constriction) and contraction of the ciliary muscle, leading to improved near-focusing but potentially causing blurred vision for distant obj
What is the method of administration for Bethanechol?
A. Intravenous
B. Oral
C. Subcutaneous
D. Intramuscular
Answer: B. Oral
Rationale: Bethanechol is administered orally to treat conditions such as urinary retention. It is not given via intravenous, subcutaneous, or intramuscular routes.
What is the duration of onset for Bethanechol?
A. 5-10 minutes
B. 15-30 minutes
C. 30-60 minutes
D. 1-2 hours
Answer: C. 30-60 minutes
Rationale: The onset of action for Bethanechol is typically within 30 to 60 minutes after oral administration, making it effective for managing conditions like urinary retention within that timeframe.
What is the duration of action for Bethanechol?
A. 30 minutes
B. 1 hour
C. 2-4 hours
D. 6-8 hours
Answer: B. 1 hour
Rationale: The duration of action for Bethanechol is approximately 1 hour, which means its effects are typically felt for this length of time after administration.
Which statement is true regarding the systemic absorption of Bethanechol?
A. Bethanechol has high systemic absorption.
B. Bethanechol has minimal systemic absorption.
C. Bethanechol is only effective with intravenous administration.
D. Bethanechol has rapid systemic absorption.
Answer: B. Bethanechol has minimal systemic absorption.
Rationale: Bethanechol has minimal systemic absorption when taken orally, which helps limit systemic side effects while still providing localized therapeutic effects, particularly in the bladder.
What is the primary use of Bethanechol?
A. To decrease heart rate
B. To increase voiding pressure in urinary retention
C. To relieve constipation
D. To induce sedation
Answer: B. To increase voiding pressure in urinary retention.
Rationale: Bethanechol is primarily used to treat urinary retention by increasing voiding pressure through contraction of the detrusor muscle in the bladder, facilitating urination.
In addition to treating urinary retention, Bethanechol is also used for which condition?
A. Hypertension
B. Gastroesophageal reflux disease (GERD)
C. Diabetes mellitus
D. Asthma
Answer: B. Gastroesophageal reflux disease (GERD)
Rationale: Bethanechol is used not only to manage urinary retention but also to treat gastroesophageal reflux disease (GERD) by increasing gastric motility and enhancing lower esophageal sphincter tone, helping to reduce reflux.
Which of the following are potential adverse effects of Bethanechol on the CV system?
A. Tachycardia and hypertension
B. Bradycardia and hypotension
C. Hyperglycemia and insomnia
D. Dry mouth and constipation
Answer: B. Bradycardia and hypotension
Rationale: Bethanechol can cause bradycardia (slow heart rate) and hypotension (low blood pressure) due to its cholinergic effects on the body, which can lead to increased vagal tone. These effects are important for the nurse to monitor in patients receiving this medication.
Which of the following adverse effects should the nurse monitor for in a patient receiving Bethanechol, especially if the patient has a history of asthma?
A. Tachycardia
B. Bronchoconstriction
C. Hyperglycemia
D. Urinary retention
Answer: B. Bronchoconstriction
Rationale: Bethanechol can cause bronchoconstriction due to its stimulation of muscarinic receptors in the lungs. This effect is particularly concerning for patients with asthma, as it may exacerbate their condition by narrowing the airways. Nurses should closely monitor respiratory status in these patients.
A patient with hyperthyroidism is receiving Bethanechol. Which potential cardiovascular effect should the nurse be aware of when administering this medication?
A. Decreased heart rate and hypotension
B. Increased heart rate and potential for arrhythmia
C. Normal heart rate with no change in rhythm
D. Decreased blood pressure and bradycardia
Answer: B. Increased heart rate and potential for arrhythmia
Rationale: In patients with hyperthyroidism, the heart rate may already be elevated, and Bethanechol can exacerbate this by causing bradycardia and increasing vagal tone. However, in this context, it’s important to note that the patient’s condition may lead to increased heart rate and potential arrhythmias. Monitoring cardiac status is crucial when administering this medication to patients with hyperthyroidism.
Which of the following describes the effect of Atropine on the eyes?
A. Constriction of the pupils and near focusing
B. Contraction of the ciliary muscle for near vision
C. Relaxation of the ciliary muscle for far vision
D. Increased tear production
Answer: C. Relaxation of the ciliary muscle for far vision
Rationale: Atropine causes relaxation of the ciliary muscle, allowing the lens to focus on distant objects, which facilitates far vision. It also leads to pupil dilation (mydriasis) by blocking muscarinic receptors in the eye.
What is a potential CNS effect of Atropine at increasing doses?
A. Mild sedation followed by sleep
B. Increased focus and alertness
C. Mild excitation progressing to hallucinations and possibly death
D. Muscle relaxation without CNS involvement
Answer: C. Mild excitation progressing to hallucinations and possibly death
Rationale: In small doses, Atropine can cause mild CNS excitation. However, as doses increase, it may lead to more severe effects, including hallucinations and, at very high doses, can be fatal. This progression underscores the need for careful dosing and monitoring.
