Central Nervous System Pharmacology Practice Questions

Q: Abuse of which of the following is the most common cause of seizures:

Cocaine. ***Cocaine*** - **Cocaine** is a potent **central nervous system stimulant** that can induce seizures through neuronal excitation, vasoconstriction, and direct neurotoxicity. - Its abuse is frequently linked to a variety of neurological complications, including **ischemic stroke** and **intracranial hemorrhage**, both of which can also lower seizure threshold. *Short term barbiturates* - **Barbiturates** are **CNS depressants** often prescribed for sedation or seizure control; their withdrawal, not short-term abuse, is a more common cause of seizures. - While acute intoxication with very high doses could cause seizures, their primary effect is general CNS depression rather than excitation. *Opioids* - **Opioids primarily cause CNS depression** and are not typically associated with inducing seizures. - **Opioid withdrawal** can sometimes lead to seizures, but this is less common than with other substances and is not directly due to abuse itself. *Short term benzodiazepines* - **Benzodiazepines** are **anticonvulsants** and are commonly used to treat seizures; acute abuse is unlikely to cause seizures. - Similar to barbiturates, **benzodiazepine withdrawal** is a significant cause of seizures, but this is distinct from short-term abuse.

Q: Heart is not sensitized by –

Diethyl–ether. ***Diethyl–ether*** - Diethyl ether does not significantly **sensitize the myocardium to catecholamines**, making it less prone to inducing arrhythmias compared to other volatile anesthetics. - Its mechanism of myocardial depression is more subtle and generally involves a **direct negative inotropic effect** rather than arrhythmogenesis. *Chloroform* - Chloroform is known to **sensitize the heart to adrenaline (epinephrine)**, increasing the risk of potentially fatal **cardiac arrhythmias**, including ventricular fibrillation. - Its use has been largely abandoned due to this significant cardiac toxicity and other adverse effects like **hepatotoxicity**. *Halothane* - Halothane potentilaly **sensitizes the myocardium to catecholamines**, leading to an increased incidence of **arrhythmias**, especially when exogenous epinephrine is administered. - This effect contributes to its less favorable cardiac safety profile compared to newer inhaled anesthetics like isoflurane or desflurane.

Q: 30 year old female with partial seizure. Drug of choice:

Carbamazepine. ***Carbamazepine*** - **Carbamazepine** is a first-line drug of choice for treating **partial seizures** due to its efficacy in controlling seizure activity with a generally favorable side effect profile. - It works by blocking **voltage-gated sodium channels**, thereby stabilizing the inactivated state of Na+ channels and preventing repetitive firing of action potentials. *Phenytoin* - While **phenytoin** is effective for partial seizures by blocking **sodium channels**, its use is often limited by its non-linear kinetics and significant side effects, including **gingival hyperplasia**, hirsutism, and cerebellar atrophy with chronic use. - Due to these side effects and monitoring difficulties, it's often considered a second-line option or for acute seizure control rather than initial monotherapy. *Phenobarbitone* - **Phenobarbitone** is an older antiepileptic drug that enhances **GABAergic neurotransmission**, but it is generally not a first-line agent for partial seizures due to its sedative properties, cognitive side effects, and potential for drug interactions. - Its use has largely been replaced by newer, better-tolerated drugs as a primary treatment. *Na+ valproate* - **Sodium valproate** is a broad-spectrum antiepileptic drug effective for both partial and generalized seizures, but it is typically not the first-line drug of choice specifically for partial seizures in female patients of childbearing age due to concerns about **teratogenicity and PCOS risk**. - Its mechanism involves multiple actions, including enhancing GABA activity, blocking sodium channels, and blocking T-type calcium channels.

Q: Most common drug used in Spasticity in patients with spinal cord injury is:

Baclofen. ***Baclofen*** - **Baclofen** is the most commonly prescribed muscle relaxant for spasticity, especially in cases related to **spinal cord injury** and multiple sclerosis. - It acts as a **GABA-B receptor agonist**, reducing excitatory neurotransmitter release and thus decreasing muscle tone. *Salicylates* - **Salicylates** (e.g., aspirin) primarily act as **analgesics** and **anti-inflammatory** agents. - They are not used for treating spasticity. *Tizanidine* - **Tizanidine** is an **alpha-2 adrenergic agonist** used for spasticity, but it is generally considered a second-line agent compared to baclofen. - It works by reducing the release of excitatory amino acids, thereby enhancing presynaptic inhibition. *Diazepam* - **Diazepam** is a **benzodiazepine** that acts as a **GABA-A receptor agonist**, enhancing inhibitory neurotransmission. - While it can reduce spasticity, its sedative effects and potential for dependence make it less preferred than baclofen for chronic management in spinal cord injury.

Q: The cardiovascular side effects of Dexmedetomidine are as follows:

Hypotension and Bradycardia. ***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.

Q: Rivastigmine & donepezil are drugs used predominantly in the management of ?

Dementia. ***Dementia*** - **Rivastigmine** and **donepezil** are **acetylcholinesterase inhibitors** that increase acetylcholine levels in the brain. - This mechanism is primarily used to improve **cognitive function** in patients with **Alzheimer's disease** and other forms of dementia. *Dissociation* - Dissociation involves a mental process causing a lack of connection between thoughts, memory, and identity, and is not typically treated with cholinesterase inhibitors. - Management often involves **psychotherapy** and sometimes anti-anxiety medications or antidepressants, if comorbid conditions are present. *Delusions* - Delusions are fixed, false beliefs often associated with psychotic disorders like **schizophrenia** or severe mood disorders. - Treatment primarily involves **antipsychotic medications**, not acetylcholinesterase inhibitors. *Depression* - Depression is a mood disorder characterized by persistent sadness and loss of interest. - It is typically treated with **antidepressants** (e.g., SSRIs, SNRIs), psychotherapy, or lifestyle changes, none of which include rivastigmine or donepezil.

Q: All of the following can be used in increased intracranial tension (ICT) except:

Ketamine. ***Ketamine*** - **Ketamine** is known to increase **cerebral blood flow** and **intracranial pressure (ICP)**, making it contraindicated in situations of increased ICT. - Its mechanism involves **cerebral vasodilation** and direct central nervous system stimulation, which can exacerbate existing intracranial hypertension. *Thiopentone* - **Thiopentone** is a barbiturate that reduces cerebral metabolic rate, leading to decreased **cerebral blood flow** and **ICP**. - It is often used for neuroprotection and to manage acute increases in ICT due to its potent vasoconstrictive effects on cerebral vessels. *Acetazolamide* - **Acetazolamide** is a **carbonic anhydrase inhibitor** that reduces **cerebrospinal fluid (CSF) production**, thus lowering ICT. - It is particularly useful in conditions like **idiopathic intracranial hypertension (pseudotumor cerebri)** where CSF overproduction contributes to elevated pressure. *Mannitol* - **Mannitol** is an **osmotic diuretic** that creates an osmotic gradient, drawing water from the brain parenchyma into the intravascular space, thereby reducing brain volume and **ICP**. - It is a rapid-acting agent frequently used in emergency settings for acute management of increased ICT.

Q: Which of the following is used in the treatment of Multiple Sclerosis:

Interferon Beta. ***Interferon Beta*** - **Interferon beta** is a disease-modifying therapy commonly used for **relapsing-remitting multiple sclerosis (RRMS)** to reduce the frequency and severity of relapses. - It works by modulating the immune system, decreasing inflammation and preventing demyelination in the central nervous system. *Interferon Alpha* - **Interferon alpha** is primarily used in the treatment of certain **cancers** (e.g., leukemia, melanoma) and **viral infections** (e.g., chronic hepatitis B and C). - It does not have a recognized role in the standard treatment protocols for multiple sclerosis. *Infliximab* - **Infliximab** is a **monoclonal antibody** that targets **tumor necrosis factor-alpha (TNF-α)** and is used in the treatment of inflammatory conditions like rheumatoid arthritis, Crohn's disease, and ulcerative colitis. - While TNF-α plays a role in inflammation, **anti-TNF therapy** has been shown to potentially worsen MS and is generally contraindicated. *Interferon gamma* - **Interferon gamma** is a pro-inflammatory cytokine that can exacerbate MS symptoms and **increase disease activity**. - It is **not used** in the treatment of multiple sclerosis and in fact, some studies suggest it may be detrimental.

Q: Renal stones are seen as a complication by using the following drug:

Zonisamide. ***Zonisamide*** - **Zonisamide** is a sulfonamide derivative that can inhibit **carbonic anhydrase**, leading to metabolic acidosis and increased urinary calcium excretion, which promotes the formation of **kidney stones**. - Patients on zonisamide should be monitored for **renal stone formation** and advised to maintain adequate hydration. *Oxcarbazepine* - **Oxcarbazepine** is an antiepileptic drug known for causing **hyponatremia** and, less commonly, dermatological reactions such as rash. - It is not typically associated with a significant risk of **renal stone formation**. *Phenytoin* - **Phenytoin** is an older antiepileptic drug commonly associated with side effects such as **gingival hyperplasia**, hirsutism, and folate deficiency. - While it has various side effects, **nephrolithiasis** (kidney stones) is not a common or recognized complication. *Tiagabine* - **Tiagabine** is an antiepileptic drug that works by inhibiting GABA reuptake. Its main side effects include dizziness, weakness, and somnolence. - There is no significant evidence to suggest that **tiagabine** causes **renal stone formation**.

Q: Which is given to prevent relapse in multiple sclerosis?

IFN-beta. ***Correct: IFN-beta*** - **Interferon-beta** is a disease-modifying therapy (DMT) commonly prescribed to **reduce the frequency and severity of relapses** and slow disease progression in **relapsing-remitting multiple sclerosis (RRMS)** [1], [2]. - Its mechanism of action involves **modulating the immune system**, reducing inflammation, and preventing immune cells from attacking the myelin sheath in the central nervous system. *Incorrect: Corticosteroids* - **Corticosteroids** (e.g., methylprednisolone) are primarily used for **acute treatment of MS relapses** to shorten their duration and severity, not for long-term relapse prevention [1]. - Their long-term use is limited by significant side effects, making them unsuitable as chronic preventive therapy [1]. *Incorrect: IFN-gamma* - **Interferon-gamma** has been shown to **exacerbate MS symptoms** and increase relapse rates, making it contraindicated in MS treatment. - It promotes a **pro-inflammatory immune response**, which is detrimental in an autoimmune demyelinating disease like MS. *Incorrect: Cyclosporine* - **Cyclosporine** is an immunosuppressant primarily used to prevent **organ transplant rejection** and in some severe autoimmune conditions. - While it has immunomodulatory properties, it is **not a first-line or standard treatment for MS relapse prevention** due to its significant toxicity profile (e.g., nephrotoxicity) and less favorable efficacy compared to approved DMTs.

Question 1

Abuse of which of the following is the most common cause of seizures:

Accepted Answer

Cocaine

Answer

Short term barbiturates

Answer

Opioids

Answer

Short term benzodiazepines

Question 2

Heart is not sensitized by –

Accepted Answer

Diethyl–ether

Answer

Chloroform

Answer

Halothane

Answer

None of the above

Question 3

30 year old female with partial seizure. Drug of choice:

Accepted Answer

Carbamazepine

Answer

Phenytoin

Answer

Phenobarbitone

Answer

Na+ valproate

Question 4

Most common drug used in Spasticity in patients with spinal cord injury is:

Accepted Answer

Baclofen

Answer

Salicylates

Answer

Tizanidine

Answer

Diazepam

Question 5

The cardiovascular side effects of Dexmedetomidine are as follows:

Accepted Answer

Hypotension and Bradycardia

Answer

Hypertension and Tachycardia

Answer

Hypertension and Bradycardia

Answer

Hypotension and Tachycardia

Question 6

Rivastigmine & donepezil are drugs used predominantly in the management of ?

Accepted Answer

Dementia

Answer

Dissociation

Answer

Delusions

Answer

Depression

Question 7

All of the following can be used in increased intracranial tension (ICT) except:

Accepted Answer

Ketamine

Answer

Thiopentone

Answer

Acetazolamide

Answer

Mannitol

Question 8

Which of the following is used in the treatment of Multiple Sclerosis:

Accepted Answer

Interferon Beta

Answer

Interferon Alpha

Answer

Infliximab

Answer

Interferon gamma

Question 9

Renal stones are seen as a complication by using the following drug:

Accepted Answer

Zonisamide

Answer

Oxcarbazepine

Answer

Phenytoin

Answer

Tiagabine

Question 10

Which is given to prevent relapse in multiple sclerosis?

Accepted Answer

IFN-beta

Answer

Corticosteroids

Answer

IFN-gamma

Answer

Cyclosporine

Central Nervous System Pharmacology — MCQs

Central Nervous System Pharmacology — MCQs

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