Pharmacology Chapter 12: Cholinergic Drugs

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Questions and Answers

What is the primary use of benztropine (Cogentin)?

As an antidote for anticholinergic toxicity

To reduce muscular tremor and rigidity (correct)

To treat bradycardia

To manage motion sickness

Which condition is scopolamine (Transderm-Scop) primarily used to prevent?

Cardiac arrest

Hypertension

Respiratory distress

Motion sickness (correct)

What is the action of physostigmine in relation to acetylcholine?

Inhibits its release

Prevents its destruction (correct)

Stimulates its production

Blocks its effects

What is a significant side effect of atropine?

Increased heart rate Signup and view all the answers

Which adrenergic receptor is primarily involved in the treatment of hypertension through inhibition of norepinephrine release?

Alpha 2 Signup and view all the answers

What therapeutic class does atropine belong to?

Anticholinergic Signup and view all the answers

What adverse effect can result from administering physostigmine too quickly?

Severe bradycardia Signup and view all the answers

What condition should be monitored when administering atropine?

Respiration and blood pressure Signup and view all the answers

What symptoms are characteristic of Myasthenia gravis?

Extreme fatigue and double vision Signup and view all the answers

What is the primary action of pyridostigmine in treating Myasthenia gravis?

Stimulates skeletal muscle contraction Signup and view all the answers

Which of the following symptoms is NOT associated with cholinergic crisis?

Increased heart rate Signup and view all the answers

What effect does Bethanechol have in the treatment of urinary retention?

It stimulates parasympathetic stimulation Signup and view all the answers

Which side effect is commonly associated with cholinergic drugs like Bethanechol?

Abdominal cramping Signup and view all the answers

What is the mechanism of action of anticholinergic drugs?

Inhibiting the action of acetylcholine Signup and view all the answers

What potential risk is associated with anticholinergic drugs in men with prostate disorders?

Increased risk of urinary retention Signup and view all the answers

Which of the following describes a classic symptom of cholinergic drugs' overactivity?

Hot as Hades Signup and view all the answers

Study Notes

Cholinergic Drugs and Myasthenia Gravis

Myasthenia gravis (MG) is a chronic condition with no cure, characterized by antibodies attacking nicotinic synapses on skeletal muscles.
Symptoms of MG include extreme fatigue, diplopia (double vision), speech difficulties, and challenges with chewing or swallowing.
Pyridostigmine (Mestinon) and neostigmine enhance skeletal muscle contraction, alleviating severe muscle weakness.

Cholinergic Agonist Drugs

Cholinergic agonists promote parasympathetic nervous system activity, resulting in increased secretions and muscle contractions.
A cholinergic crisis can occur with symptoms like fever, visual disturbances, and hallucinations, remembered by the phrase "Hot as Hades, blind as a bat, dry as a bone, mad as a hatter."
Bethanechol (Duvoid, Urecholine) stimulates smooth muscle contraction in the digestive and urinary tracts; used for non-obstructive urinary retention in atonic bladder conditions.
Caution is advised during administration; monitor vital signs and be aware of side effects, including increased salivation and hypotension. Atropine serves as a specific antidote.

Anticholinergic Drugs

Anticholinergics inhibit acetylcholine (ACh) at cholinergic synapses, leading to symptoms consistent with "fight-or-flight" response.
Common effects include tachycardia, CNS stimulation, urinary retention, and decreased sweating, potentially causing hyperthermia.
Benztropine (Cogentin) helps alleviate tremors and rigidity in Parkinson's disease.
Scopolamine (Transderm-Scop) is effective for sedation and preventing motion sickness.

Antidote and Interactions

Physostigmine serves as an antidote for anticholinergic toxicity by inhibiting ACh breakdown; must be administered slowly to prevent seizures.
Atropine is an anti-bradycardic and antidote for cholinesterase poisoning; it counteracts parasympathetic actions of ACh to stimulate the sympathetic response.
Side effects of atropine include dry mouth, constipation, and potential CNS depression leading to coma. It's contraindicated in patients with glaucoma and certain gastrointestinal obstructions.

Adrenergic Drugs

Adrenergic receptors are categorized as alpha and beta receptors, each with different physiological roles.
Alpha1 receptors affect all sympathetic target organs except the heart, causing blood vessel constriction and pupil dilation (mydriasis); used in shock treatment and nasal congestion.
Alpha2 receptors inhibit norepinephrine release; they are used to treat hypertension through central nervous system mechanisms.
Beta1 receptors, found in the heart and kidneys, increase heart rate and contractility, alongside renin release; employed in managing cardiac arrest and heart failure.
Beta2 receptors relax smooth muscle and are pivotal in treating asthma and COPD; albuterol is a notable medication used in these cases.

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Description

This quiz covers Chapter 12 on cholinergic drugs and their effects on the autonomic nervous system, particularly in relation to myasthenia gravis (MG). It highlights how drugs like pyridostigmine and neostigmine are used to manage symptoms by stimulating skeletal muscle contraction. Test your knowledge on the mechanisms and implications of these medications.