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 Indian Medical PG Question 6: A mother reports that her daughter ingested a substance in an unknown dose. The girl presents with hypertension, tachycardia, mydriasis, and hyperthermia. What is the most likely substance?

• A. Heroin
• B. Morphine
• C. Cocaine (Correct Answer)
• D. Chlorpheniramine
• E. Organophosphate

Autonomic Nervous System Drugs Explanation: ***Cocaine*** - The presented symptoms of **hypertension, tachycardia, mydriasis, and hyperthermia** are characteristic of a **sympathomimetic toxidrome**, frequently caused by cocaine overdose. - Cocaine acts as a **norepinephrine-dopamine-serotonin reuptake inhibitor**, leading to excessive stimulation of the central and peripheral nervous systems. *Heroin* - Heroin is an **opioid**, and overdose generally presents with **respiratory depression, bradycardia, miosis (pinpoint pupils)**, and hypotension, which are contrary to the patient's symptoms. - Patients typically exhibit central nervous system **depression**, rather than the hyperactive state seen here. *Morphine* - Similar to heroin, morphine is an **opioid** and causes symptoms like **respiratory depression, bradycardia, miosis**, and hypotension. - These effects are the opposite of the **sympathomimetic** signs observed in the patient. *Chlorpheniramine* - Chlorpheniramine is an **antihistamine** with significant **anticholinergic effects**. An overdose might cause **mydriasis and tachycardia**, but not typically severe hypertension or hyperthermia as the primary features. - Other anticholinergic signs such as **dry mucous membranes, urinary retention, and altered mental status (delirium)** would also be expected. *Organophosphate* - Organophosphate poisoning causes a **cholinergic toxidrome** due to **acetylcholinesterase inhibition**, resulting in excessive cholinergic stimulation. - Classic presentation includes **SLUDGE syndrome** (Salivation, Lacrimation, Urination, Defecation, GI upset, Emesis) along with **miosis (pinpoint pupils), bradycardia, bronchospasm**, and muscle fasciculations. - These findings are the **opposite** of the sympathomimetic signs seen in this patient.

Autonomic Nervous System Drugs Indian Medical PG Question 7: An induction agent of choice for poor-risk patients with cardiorespiratory disease as well as in situations where preservation of a normal blood pressure is crucial:-

• A. Ketamine
• B. Etomidate (Correct Answer)
• C. Propofol
• D. Thiopentone

Autonomic Nervous System Drugs Explanation: ***Etomidate*** - Etomidate is preferred in patients with **cardiac disease** or **hemodynamic instability** due to its minimal effects on cardiovascular function. - It maintains **cardiovascular stability**, including myocardial contractility and blood pressure, making it ideal for procedures where maintaining a normal blood pressure is crucial. *Ketamine* - Ketamine often causes a **sympathetic stimulating effect**, leading to increases in heart rate and blood pressure, which may be detrimental in such patients. - It is associated with **tachycardia** and **hypertension**, undesirable in a poor-risk patient with cardiorespiratory disease. *Propofol* - Propofol is a potent **vasodilator** and myocardial depressant, which can lead to significant **hypotension**, especially in volume-depleted or critically ill patients. - Its use can result in a dose-dependent decrease in **arterial blood pressure** and **cardiac output**. *Thiopentone* - Thiopentone can cause **myocardial depression** and significant **hypotension**, especially in patients with compromised cardiovascular function. - It leads to a notable decrease in **vascular tone** and venous return, thus lowering blood pressure.

Autonomic Nervous System Drugs Indian Medical PG Question 8: Continued suppression of bacterial growth after antibiotic levels have fallen below the Minimum Inhibitory Concentration (MIC) is known as?

• A. Time dependent killing
• B. Sequential blockade
• C. Concentration dependent killing
• D. Post antibiotic effect (Correct Answer)

Autonomic Nervous System Drugs Explanation: ***Post antibiotic effect*** - The **post-antibiotic effect (PAE)** refers to the continued suppression of bacterial growth after antibiotic levels have fallen below the **Minimum Inhibitory Concentration (MIC)**. - This phenomenon allows for less frequent dosing while maintaining efficacy, which is important for drug scheduling. *Time dependent killing* - **Time-dependent killing** means that the duration for which the antibiotic concentration stays above the **MIC** is the most important factor for efficacy, not necessarily the peak concentration. - Antibiotics with this characteristic, such as **beta-lactams**, often require frequent dosing or continuous infusion. *Sequential blockade* - **Sequential blockade** occurs when two drugs act on consecutive steps in a metabolic pathway, leading to a synergistic effect that results in enhanced microbial killing. - A classic example is the combination of **sulfamethoxazole and trimethoprim**, which inhibit different enzymes in the folic acid synthesis pathway. *Concentration dependent killing* - **Concentration-dependent killing** indicates that the rate and extent of bacterial killing increase as the antibiotic concentration rises, particularly when it exceeds the **MIC**. - Antibiotics like **aminoglycosides** exhibit this effect, often benefiting from high peak concentrations to maximize efficacy.

Autonomic Nervous System Drugs Indian Medical PG Question 9: Ocular effects that include mydriasis are characteristic of which of the following drugs?

• A. phenylephrine (alpha agonist) (Correct Answer)
• B. neostigmine (cholinesterase inhibitor)
• C. phentolamine (alpha blocker)
• D. mecamylamine (ganglionic blocker)

Autonomic Nervous System Drugs Explanation: ***phenylephrine (alpha agonist)*** - **Phenylephrine** is a direct-acting **alpha-1 adrenergic agonist** that causes contraction of the **pupillary dilator muscle**, leading to **mydriasis** (pupil dilation). [1] - It is frequently used clinically to dilate pupils for **ophthalmologic examinations** due to its selective action on alpha-1 receptors in the eye. [2] *neostigmine (cholinesterase inhibitor)* - **Neostigmine** inhibits acetylcholinesterase, increasing acetylcholine at the neuromuscular junction and muscarinic receptors. This leads to **miosis** (pupil constriction), not mydriasis. - Its ophthalmic use is primarily for treating **glaucoma** by improving aqueous humor outflow through cholinergic effects on the ciliary muscle. *phentolamine (alpha blocker)* - **Phentolamine** is a **non-selective alpha-adrenergic antagonist** that blocks both alpha-1 and alpha-2 receptors. - Alpha-1 receptor blockade in the eye would relax the pupillary dilator muscle, leading to **miosis** or prevention of mydriasis, not its induction. *mecamylamine (ganglionic blocker)* - **Mecamylamine** is a **ganglionic blocker** that antagonizes nicotinic receptors in both sympathetic and parasympathetic ganglia. - Blocking parasympathetic ganglia can cause some mydriasis, but ganglionic blockers have widespread, non-selective autonomic effects and are not primarily used for isolated mydriasis.

Autonomic Nervous System Drugs Indian Medical PG Question 10: The cardiovascular side effects of Dexmedetomidine are as follows:

• A. Hypertension and Tachycardia
• B. Hypertension and Bradycardia
• C. Hypotension and Bradycardia (Correct Answer)
• D. Hypotension and Tachycardia

Autonomic Nervous System Drugs Explanation: ***Hypotension and Bradycardia*** - **Dexmedetomidine** is an **alpha-2 adrenergic agonist** that causes a dose-dependent decrease in heart rate (bradycardia) and blood pressure (hypotension) due to reduced sympathetic outflow. - The initial hypertensive effect seen with rapid IV administration is usually transient and followed by sustained hypotension. *Hypertension and Tachycardia* - This combination is not typical for **dexmedetomidine**, which primarily exerts its effects by centrally reducing sympathetic tone, leading to lowered heart rate and blood pressure. - **Tachycardia** is a rare and usually reflex-mediated response if severe hypotension occurs, but it's not a primary effect. *Hypertension and Bradycardia* - While an initial, transient **hypertension** can occur with rapid **dexmedetomidine** infusion due to peripheral alpha-2 stimulation, this is not its predominant long-term cardiovascular effect. - The sustained effect is usually **hypotension**, not hypertension, making this option incorrect as a primary side effect. *Hypotension and Tachycardia* - Although **hypotension** is a common side effect of **dexmedetomidine**, **tachycardia** is generally not. - The drug mainly causes a reduction in heart rate (**bradycardia**) as part of its central sympatholytic action.

Autonomic Nervous System Drugs Flashcard 1 of 10

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

Answer: Gallamine, Rocuronium and Pancuronium

Autonomic Nervous System Drugs Flashcard 2 of 10

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

Answer: Muscarinic

Autonomic Nervous System Drugs Flashcard 3 of 10

Question: Dipivefrine and dopexamine are 2-adrenergic receptor _____

Answer: agonists

Autonomic Nervous System Drugs Flashcard 4 of 10

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

Answer: M1

Autonomic Nervous System Drugs Flashcard 5 of 10

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

Answer: beta

Autonomic Nervous System Drugs Flashcard 6 of 10

Question: Autonomics_____ is a non-selective irreversible 1 and 2 adrenergic receptor antagonist

Answer: Phenoxybenzamine

Autonomic Nervous System Drugs Flashcard 7 of 10

Question: The following is a flower of? _____

Answer: Atropa belladonna

Autonomic Nervous System Drugs Flashcard 8 of 10

Question: The image shows _____ fruit, where the active principle is atropine, scopolamine and hyoscyamine

Answer: Datura

Autonomic Nervous System Drugs Flashcard 9 of 10

Question: malathion effect lasts for _____ time

Answer: 3 months

Extra Information: 

Autonomic Nervous System Drugs Flashcard 10 of 10

Question: Specific adverse effects of timolol: allergic _____ and punctal stenosis

Answer: blepharoconjunctivitis