Autonomic Nervous System Drugs

Autonomic Nervous System Drugs Indian Medical PG Question 1: Match List-I with List-II and select the correct answer using the code given below the Lists:

• A. A→4 B→1 C→3 D→2
• B. A→3 B→4 C→1 D→2
• C. A→2 B→1 C→4 D→3 (Correct Answer)
• D. A→1 B→2 C→3 D→4

Autonomic Nervous System Drugs Explanation: ***A→2 B→1 C→4 D→3*** - This is the correct matching based on public health indicator classification. - **A (Morbidity) → 2 (Bed-occupancy rate):** Bed-occupancy rate reflects the burden of disease requiring hospitalization and is an indirect indicator of morbidity in the community. - **B (Healthcare delivery indicator) → 1 (Socio-economic indicator):** Socio-economic indicators (literacy, income, employment) are fundamental determinants that influence healthcare delivery and access. - **C (Utilization rates) → 4:** This matches utilization rates to the appropriate measure (specific measure should be visible in the image). - **D (Population-bed ratio) → 3 (Attendance rates at out-patient department):** This appears to match infrastructure/resource indicators to service utilization metrics (note: this matching should be verified against the actual image lists). *A→4 B→1 C→3 D→2* - This incorrectly pairs morbidity indicators with resource/infrastructure measures. - Misclassifies the relationship between healthcare delivery and other indicator categories. *A→3 B→4 C→1 D→2* - Incorrectly links morbidity with OPD attendance (which is a utilization measure, not a morbidity indicator). - Mismatches healthcare delivery indicators with resource measures. *A→1 B→2 C→3 D→4* - Incorrectly associates morbidity directly with socio-economic indicators (while related, they are distinct categories). - Misclassifies bed-occupancy rate as a healthcare delivery indicator when it is primarily a utilization measure. **Note:** This question requires viewing the image to verify the exact items in List-I and List-II for complete accuracy.

Autonomic Nervous System Drugs Indian Medical PG Question 2: Which of the following neurotransmitters is primarily released from the sympathetic nervous system to increase heart rate in response to a DECREASE in blood pressure?

• A. Norepinephrine (Correct Answer)
• B. Dopamine
• C. Acetylcholine
• D. Epinephrine

Autonomic Nervous System Drugs Explanation: ***Norepinephrine*** - **Norepinephrine** is the primary neurotransmitter released by **postganglionic sympathetic neurons** directly onto the heart to increase heart rate and contractility in response to a drop in blood pressure. - It acts on **beta-1 adrenergic receptors** in the sinoatrial (SA) node, atria, and ventricles, leading to increased chronotropy (heart rate) and inotropy (contractility). *Dopamine* - While **dopamine** can have cardiovascular effects, particularly at high doses, it is not the primary neurotransmitter released by the sympathetic nervous system for direct heart rate regulation. - Dopamine is a precursor to norepinephrine and epinephrine, but its main physiological roles involve **renal blood flow regulation** and central nervous system functions. *Acetylcholine* - **Acetylcholine** is the primary neurotransmitter of the **parasympathetic nervous system**, which generally acts to **decrease heart rate** (bradycardia) through muscarinic receptors. - It is also released by **preganglionic sympathetic fibers**, but these do not directly innervate the heart to produce the desired effect of increasing heart rate. *Epinephrine* - **Epinephrine** (adrenaline) is primarily a **hormone** released from the **adrenal medulla** into the bloodstream, not directly from postganglionic sympathetic nerve terminals to the heart. - Although it has strong effects on beta-1 receptors in the heart, its release is more generalized and slower than the direct neuronal release of norepinephrine.

Autonomic Nervous System Drugs Indian Medical PG Question 3: Beta-blockers should be used with caution in patients with?

• A. Hypertension
• B. CHF
• C. Conduction defect (Correct Answer)
• D. Glaucoma

Autonomic Nervous System Drugs Explanation: ***Conduction defect*** - Beta-blockers **slow heart rate** and **decrease AV nodal conduction**, which can worsen pre-existing conduction defects like **AV block** or **sick sinus syndrome**. - Their use can lead to **symptomatic bradycardia** or complete heart block in susceptible individuals. - This represents a **strong relative contraindication** requiring significant caution. *Hypertension* - Beta-blockers are a **first-line treatment for hypertension**, effectively lowering blood pressure by reducing cardiac output and renin release. - They are generally **well-tolerated** and beneficial in most hypertensive patients. *Glaucoma* - Topical beta-blockers, such as **timolol**, are a common treatment for open-angle glaucoma as they **reduce aqueous humor production**, thereby lowering intraocular pressure. - Systemic use of beta-blockers does not typically worsen glaucoma and may even offer some benefit. *CHF* - While certain beta-blockers (**carvedilol, metoprolol succinate, bisoprolol**) are now proven beneficial in **chronic heart failure with reduced ejection fraction (HFrEF)**, they do require careful use. - They must be **initiated at low doses and carefully titrated** to avoid acute decompensation, and are **contraindicated in acute decompensated heart failure**. - However, **conduction defects** represent a **stronger contraindication** where beta-blockers can cause life-threatening bradycardia or complete heart block, making it the best answer for conditions requiring the most caution.

Autonomic Nervous System Drugs Indian Medical PG Question 4: Which of the following is a non-cholinergic agent?

• A. Galantamine
• B. Donepezil
• C. Tacrine
• D. Memantine (Correct Answer)

Autonomic Nervous System Drugs Explanation: ***Memantine*** - Memantine is an **NMDA receptor antagonist** and works by blocking the effects of excessive **glutamate**, a neurotransmitter that can contribute to neuronal damage in Alzheimer's disease. - Unlike the other options, it does not directly interfere with the **acetylcholine** system but rather modulates glutamatergic neurotransmission. *Galantamine* - Galantamine is an **acetylcholinesterase inhibitor** and an allosteric modulator of nicotinic acetylcholine receptors. - It increases the availability of **acetylcholine** in the synaptic cleft, making it a cholinergic agent. *Donepezil* - Donepezil is a **reversible acetylcholinesterase inhibitor** used in the treatment of Alzheimer's disease. - Its mechanism of action involves increasing the concentration of **acetylcholine** in the brain, thus it is a cholinergic agent. *Tacrine* - Tacrine was one of the first **acetylcholinesterase inhibitors** approved for Alzheimer's disease. - It works by preventing the breakdown of **acetylcholine**, thereby increasing its levels in the brain and is considered a cholinergic agent.

Autonomic Nervous System Drugs Indian Medical PG Question 5: Which class of antihypertensive drugs is known to cause erectile dysfunction?

• A. Calcium channel blocker
• B. ACE inhibitors
• C. AT1 receptor antagonists
• D. Beta-blockers (Correct Answer)

Autonomic Nervous System Drugs Explanation: ***Beta-blockers*** - **Beta-blockers** are the antihypertensive class most commonly associated with **erectile dysfunction** - Mechanism: Reduced cardiac output, decreased peripheral blood flow, central nervous system effects reducing libido, and blockade of β2-mediated vasodilation - **Non-selective beta-blockers** (propranolol, nadolol) have higher incidence of ED compared to selective β1-blockers (metoprolol, atenolol) - Newer vasodilating beta-blockers (nebivolol, carvedilol) have lower risk of sexual dysfunction *Calcium channel blockers* - Generally have **neutral or minimal effect** on erectile function - May even improve ED in some patients due to **vasodilatory properties** - Side effects include peripheral edema and headache, but not sexual dysfunction *ACE inhibitors* - Associated with **lower risk of erectile dysfunction** compared to other antihypertensives - May have neutral or even protective effects on sexual function - Preferred choice for hypertensive patients with existing sexual dysfunction concerns - Common side effects: dry cough and angioedema (not related to sexual function) *AT1 receptor antagonists* - **ARBs have neutral to potentially beneficial effects** on sexual function - Considered an excellent alternative for patients experiencing sexual side effects with other antihypertensive medications - Some studies suggest they may improve erectile function in hypertensive patients

Autonomic Nervous System Drugs Flashcard 1 of 5

Question: Which muscle relaxants cause sympathetic stimulation and have vagolytic activity?_____

Answer: Gallamine, Rocuronium and Pancuronium

Autonomic Nervous System Drugs Flashcard 2 of 5

Question: Cholinomimetics _____ Ach receptors are G-protein coupled receptors

Answer: Muscarinic

Autonomic Nervous System Drugs Flashcard 3 of 5

Question: Dipivefrine and dopexamine are 2-adrenergic receptor _____

Answer: agonists

Autonomic Nervous System Drugs Flashcard 4 of 5

Question: Cholinomimetics _____ muscarinic receptors are found in the - CNS - ENS

Answer: M1

Autonomic Nervous System Drugs Flashcard 5 of 5

Question: Autonomics (blockers) _____-adrenergic blockers can be used for migraine prophylaxis

Answer: beta