Autonomic Pharmacology – Practice Flashcards

A comprehensive set of question-and-answer flashcards covering the key clinical applications, mechanisms, and toxicities of autonomic drugs discussed in the lecture on autonomic pharmacology.

What is the primary therapeutic goal of β-adrenoceptor antagonists in ischaemic heart disease?

To reduce cardiac output and workload during each heartbeat.

Which non-selective β-blocker is commonly used orally to treat IHD and hypertension?

Propranolol.

Why is propranolol contraindicated in asthmatic patients?

Because its β2 antagonism can trigger bronchoconstriction and fatal bronchospasm.

Which β1-selective antagonist can be used in asthmatics with heart disease to avoid bronchospasm?

Atenolol.

What β2-selective agonist is inhaled as a bronchodilator for asthma?

Salbutamol.

What are the characteristic airway changes during an asthma attack?

Constriction of bronchioles leading to wheezing, breathlessness, coughing, and a tight chest.

Which adrenoceptor subtype mediates bronchodilation?

β2 adrenoceptors.

What sympathomimetic drug is administered in anaphylactic shock to restore airway patency and blood pressure?

Adrenaline (epinephrine).

List the three main cardiovascular effects of adrenaline during anaphylaxis.

Bronchodilation via β2, increased heart rate and cardiac output via β1, and peripheral vasoconstriction via α1/α2.

Give three examples of indirectly acting sympathomimetic drugs that block noradrenaline re-uptake.

Cocaine, amphetamine, and tricyclic antidepressants such as amitriptyline.

What phrase summarizes overall parasympathetic function?

“Rest and Digest.”

Which muscarinic receptor subtype is primarily responsible for slowing heart rate?

M2 receptors.

Which muscarinic receptor subtype mediates glandular secretion and smooth-muscle contraction?

M3 receptors.

Name four classic effects of muscarinic stimulation on exocrine glands.

Salivation, lacrimation, sweating, and increased bronchial secretion.

What natural alkaloid from Atropa belladonna is a potent muscarinic antagonist?

Atropine.

List four peripheral symptoms of atropine poisoning.

Mydriasis, dry mouth, tachycardia, and hot but dry skin.

Which mushroom contains muscarine, a potent muscarinic agonist?

Amanita muscaria (Fly agaric).

Why can ingestion of muscarine be fatal?

Excessive parasympathetic stimulation causes severe bradycardia, bronchoconstriction, and secretions leading to cardiorespiratory failure.

What muscarinic antagonist is used to treat overactive bladder and urge incontinence?

Oxybutynin.

Why does oxybutynin produce side-effects such as blurred vision and dry mouth?

Because it is a non-selective M2/M3 antagonist that blocks muscarinic receptors in many tissues.

Which muscarinic agonist is used topically to constrict the pupil and lower intra-ocular pressure in glaucoma?

Pilocarpine.

How does pilocarpine reduce intra-ocular pressure?

It causes miosis that opens the trabecular drainage canal, increasing aqueous humour outflow.

Which muscarinic antagonist is used to produce mydriasis and cycloplegia for eye examination?

Atropine (now often replaced by tropicamide).

What enzyme rapidly terminates acetylcholine action at synapses?

Acetylcholinesterase (AChE).

How do anticholinesterase drugs act as indirectly acting parasympathomimetics?

They inhibit AChE, elevating and prolonging ACh at muscarinic and nicotinic receptors.

Name two reversible anticholinesterases and one clinical use for each.

Physostigmine – glaucoma or atropine poisoning; Neostigmine – myasthenia gravis or postoperative urinary retention.

What class of compounds irreversibly inhibits AChE via phosphorylation?

Organophosphorus compounds (e.g., dyflos, sarin, VX, Novichok).

List four muscarinic signs of organophosphate poisoning.

Miosis, salivation, sweating, and bradycardia.

What is the first-line drug to counteract muscarinic symptoms in organophosphate poisoning?

Atropine.

Which oxime can reactivate phosphorylated AChE if given promptly?

Pralidoxime.

Why must pralidoxime be administered quickly after organophosphate exposure?

Because the phosphorylated AChE undergoes "aging," becoming irreversibly inactive.

What nicotinic effects may appear in organophosphate poisoning?

Skeletal-muscle fasciculation and paralysis due to depolarising block.

Which reversible anticholinesterase is more polar and therefore acts mainly peripherally?

Neostigmine.

In cardiac tissue, which adrenoceptor subtype maintains sympathetic tone that β-blockers target?

β1 adrenoceptors.

Define indirectly acting sympatholytic drugs.

Drugs that inhibit noradrenaline synthesis, storage, or release, thereby decreasing sympathetic activity.

What blood pressure criterion defines Stage 2 hypertension in the lecture?

Diastolic blood pressure greater than 100 mmHg.

Name two unavoidable risk factors for hypertension.

Age and genetic predisposition (sex and ethnicity are also unavoidable factors).

Which sympathetic receptor subtype, when blocked, reduces heart rate and contractility?

β1 adrenoceptors.

What is the primary goal when treating IHD and hypertension with β-blockers?

To decrease heart rate, cardiac output, and myocardial oxygen demand.

What four lifestyle factors increase risk of coronary heart disease mentioned in the lecture?

Poor diet, physical inactivity, smoking, and excessive alcohol consumption (obesity/diabetes are related).