Central Nervous System Pharmacology Practice Questions

Q: Modafinil is approved by FDA for treatment of all except:

Lethargy in depression. ***Lethargy in depression*** - Modafinil is **not FDA-approved** for treating lethargy or fatigue specifically in the context of depression. Its primary indications are for disorders of excessive daytime sleepiness. - While it may be used off-label in some cases for depression-related fatigue, it lacks formal FDA approval and specific efficacy data for this indication. *Narcolepsy* - Modafinil is **FDA-approved** as a wakefulness-promoting agent for the treatment of excessive daytime sleepiness associated with **narcolepsy**. - It helps reduce the frequency and severity of sleep attacks by promoting wakefulness through effects on **dopamine**, **norepinephrine**, and **histamine** systems in the brain. *Shift work sleep disorder (SWSD)* - Modafinil is **FDA-approved** to improve wakefulness in patients with excessive sleepiness associated with **shift work sleep disorder**. - It helps individuals working non-traditional hours (night shifts, rotating shifts) maintain alertness during their work periods. *Obstructive sleep apnea syndrome (OSAS)* - Modafinil is **FDA-approved** as an **adjunctive treatment** for residual excessive daytime sleepiness in patients with **obstructive sleep apnea/hypopnea syndrome (OSAHS)** who are receiving adequate treatment with CPAP. - It addresses persistent sleepiness that remains even after appropriate primary airway management.

Q: Which drug is suitable for epilepsy related to a brain tumor?

Levetiracetam. ***Levetiracetam*** - Levetiracetam is often preferred for **tumor-related epilepsy** due to its favorable **pharmacokinetic profile**, minimal **drug-drug interactions**, and broad spectrum of activity against various seizure types. - It does not significantly induce or inhibit hepatic enzymes, making it a safer option for patients who may be on other medications for their tumor or cancer treatment. *Phenytoin* - **Phenytoin** has a narrow **therapeutic window** and significant **drug-drug interactions** due to its potent hepatic enzyme induction, which can complicate concomitant use with **chemotherapy** or other medications. - It also has a dose-dependent non-linear pharmacokinetic profile, making dose adjustments challenging and increasing the risk of **toxicity**. *Phenobarbitone* - **Phenobarbitone** is a potent enzyme inducer and has a high potential for **sedation** and cognitive side effects, which can significantly impair the quality of life for patients. - Its long half-life and propensity for **drug interactions** make it less desirable, especially in patients with brain tumors who may experience other neurological deficits. *Carbamazepine* - **Carbamazepine** is another potent **enzyme inducer** that can lead to significant **drug interactions**, particularly with chemotherapy agents, altering their metabolism and efficacy. - It often causes side effects like **drowsiness**, **dizziness**, and can lead to **hyponatremia**, which may be problematic in patients who are already compromised.

Q: A patient with grand mal epilepsy would likely be under treatment with:

Phenytoin. ***Phenytoin*** - **Phenytoin** is a classic and effective anticonvulsant widely used for treating **generalized tonic-clonic seizures** (grand mal epilepsy) [2], [4]. - Its mechanism involves blocking voltage-gated sodium channels, stabilizing the neuronal membrane and preventing the repetitive firing of action potentials [3]. *Pentobarbital* - **Pentobarbital** is a barbiturate primarily used as a sedative or for inducing medical coma, especially in refractory status epilepticus. - While it has anticonvulsant properties, it is not a first-line agent for the long-term management of chronic grand mal epilepsy due to its side effect profile and sedative effects. *Trimethadione* - **Trimethadione** is an older anticonvulsant specifically used for **absence seizures** (petit mal epilepsy). - It works by reducing T-type calcium currents in thalamic neurons, a mechanism distinct from that required for generalized tonic-clonic seizures [1]. *Meprobamate* - **Meprobamate** is a carbamate derivative primarily used as an anxiolytic and muscle relaxant. - It has sedative properties but is not considered an effective or appropriate treatment for any type of epilepsy, including grand mal seizures.

Q: A 65-year-old gentleman is having tremors, rigidity and reduced mobility. He is likely to be benefited by?

Bromocriptine. ***Bromocriptine*** - The patient's symptoms (tremors, rigidity, reduced mobility) are classic for **Parkinson's disease**, which involves a deficiency of **dopamine** [1]. - **Bromocriptine** is a **dopamine agonist** that directly stimulates dopamine receptors, thereby alleviating Parkinsonian symptoms [2]. *Reserpine* - **Reserpine** depletes **monoamines**, including dopamine, by inhibiting their uptake into synaptic vesicles. - This action would worsen Parkinsonian symptoms rather than improve them. *Acyclovir* - **Acyclovir** is an **antiviral agent** used to treat herpes virus infections. - It has no role in the management of movement disorders like Parkinson's disease. *Alpha methyl dopa* - **Alpha-methyldopa** is an **antihypertensive agent** that reduces sympathetic outflow by acting as an alpha-2 adrenergic agonist. - It does not address the dopamine deficiency seen in Parkinson's disease and is not used to treat movement disorders.

Q: The following drugs are used for prophylaxis of migraine except

Meperidine. ***Meperidine*** - **Meperidine** (pethidine) is an **opioid analgesic** primarily used for acute pain relief, not for migraine prophylaxis. - Its use can lead to **opioid dependence** and even worsen headache frequency in the long term, known as medication overuse headache. *Metoprolol* - **Metoprolol** is a **beta-blocker** commonly prescribed for migraine prophylaxis, especially in patients with co-existing hypertension or anxiety. - It works by modulating **adrenergic activity** and is considered a first-line agent for preventing migraine attacks. *Valproate* - **Valproate** (valproic acid/divalproex sodium) is an **anticonvulsant** that is effective in migraine prophylaxis. - It is thought to work by increasing **GABA activity** and modulating neuronal excitability, reducing migraine frequency. *Topiramate* - **Topiramate** is an **anticonvulsant** frequently used for migraine prophylaxis, particularly favored for its potential side effect of **weight loss**. - Its mechanism involves multiple actions, including **GABA potentiation**, glutamate antagonism, and modulation of voltage-gated ion channels.

Q: Drugs used for Prophylaxis of migraine include the following except?

Sumatriptan. ***Sumatriptan*** - **Sumatriptan** is a **triptan** drug class medication (5-HT1B/1D receptor agonist) used for the **acute treatment** of migraine attacks, not for prophylaxis. - It works by causing cranial vasoconstriction and inhibiting neuropeptide release, thereby aborting an active migraine attack. - Triptans are contraindicated in patients with coronary artery disease due to their vasoconstrictive effects. *Valproate* - **Valproate** (sodium valproate/divalproex) is an established **first-line agent for migraine prophylaxis**. - It exerts antimigraine effects through modulation of GABAergic transmission, voltage-gated sodium channels, and possibly NMDA receptor inhibition. - Effective dose for prophylaxis is typically 500-1000 mg/day in divided doses. *Propranolol* - **Propranolol**, a non-selective **beta-blocker**, is one of the most commonly used **first-line prophylactic agents** for migraine. - It reduces migraine frequency through multiple mechanisms including inhibition of norepinephrine, reduction of cortical spreading depression, and stabilization of vascular tone. - Typical prophylactic dose is 80-240 mg/day in divided doses. *TCAs* - **Tricyclic antidepressants (TCAs)**, particularly **amitriptyline**, are highly effective **first-line prophylactic agents** for migraine. - They work through modulation of serotonin and norepinephrine reuptake, as well as effects on ion channels and pain pathways. - Amitriptyline is typically used at doses of 25-150 mg at bedtime for migraine prophylaxis.

Q: Nephrotoxic agent is:

Methoxyflurane. ***Methoxyflurane*** - Methoxyflurane undergoes significant **metabolism** in the liver, releasing **fluoride ions** and dichloroacetic acid. - The fluoride ions can cause **dose-dependent high-output renal failure** by interfering with the kidney's concentrating ability, leading to nephrotoxicity. *N2O (Nitrous Oxide)* - While widely used, N2O is known for its ability to **oxidize vitamin B12**, which can impair methionine synthase activity. - It does not directly cause nephrotoxicity but is associated with **bone marrow suppression** with prolonged or repeated exposure. *Halothane* - Halothane is a potent **hepatotoxin**, primarily linked to **halothane-induced hepatitis**, ranging from mild liver enzyme elevation to fulminant hepatic failure. - It is not primarily associated with nephrotoxicity; its main organ toxicity concern is the **liver**. *Isoflurane* - Isoflurane is largely **excreted unchanged** by the lungs, with minimal metabolism. - Due to its low metabolism and minimal production of inorganic fluoride, it has a **low risk of nephrotoxicity**.

Q: Which of the following medications in the treatment of Parkinson's disease is an NMDA antagonist?

Amantadine. ***Amantadine*** - **Amantadine** is an **NMDA receptor antagonist**, which contributes to its antiparkinsonian effects by modulating glutamatergic neurotransmission. - It works by reducing the **excitatory effects of glutamate**, potentially improving motor fluctuations and dyskinesia in Parkinson's disease. *Selegiline* - **Selegiline** is a **selective irreversible inhibitor of monoamine oxidase B (MAO-B)**, which prevents the breakdown of dopamine. - It enhances the availability of dopamine in the brain but does not act as an NMDA antagonist. *Entacapone* - **Entacapone** is a **catechol-O-methyltransferase (COMT) inhibitor** that prevents the peripheral breakdown of levodopa. - This action increases the bioavailability of levodopa to the brain, but it is not an NMDA antagonist. *Ropinirole* - **Ropinirole** is a **dopamine agonist** that directly stimulates dopamine receptors in the brain. - It mimics the effects of dopamine but does not interact with NMDA receptors.

Q: Modafinil is used for

Narcolepsy. ***Narcolepsy*** - **Modafinil** is a **wakefulness-promoting agent** primarily used to improve wakefulness in patients with excessive daytime sleepiness associated with **narcolepsy**. - Its mechanism involves increasing levels of **dopamine** and **norepinephrine** in specific brain regions, promoting alertness without significant cardiovascular or euphoric effects. *Psychogenic erectile dysfunction* - This condition is typically treated with **phosphodiesterase-5 (PDE5) inhibitors** like sildenafil or tadalafil, which improve blood flow to the penis. - Modafinil has no established role in the treatment of erectile dysfunction, as it does not directly affect the physiological mechanisms of erection. *Orthostatic hypotension* - **Orthostatic hypotension** is managed by increasing blood volume and venoconstriction, often using medications like **fludrocortisone** or **midodrine**. - While modafinil has some sympathomimetic properties, it is not a first-line or common treatment for orthostatic hypotension. *OCD* - **Obsessive-compulsive disorder (OCD)** is primarily treated with **selective serotonin reuptake inhibitors (SSRIs)** and cognitive-behavioral therapy (CBT). - Modafinil is not indicated for OCD and would not address the underlying pathology of obsessions and compulsions.

Question 1

Modafinil is approved by FDA for treatment of all except:

Accepted Answer

Lethargy in depression

Answer

Narcolepsy

Answer

Shift work sleep disorder (SWSD)

Answer

Obstructive sleep apnea syndrome (OSAS)

Question 2

Which drug is suitable for epilepsy related to a brain tumor?

Accepted Answer

Levetiracetam

Answer

Phenytoin

Answer

Phenobarbitone

Answer

Carbamazepine

Question 3

What is the drug of choice for treatment of simple partial seizures?

Accepted Answer

Carbamazepine

Answer

Phenytoin

Answer

Valproate

Answer

Barbiturate

Question 4

A patient with grand mal epilepsy would likely be under treatment with:

Accepted Answer

Phenytoin

Answer

Pentobarbital

Answer

Trimethadione

Answer

Meprobamate

Question 5

A 65-year-old gentleman is having tremors, rigidity and reduced mobility. He is likely to be benefited by?

Accepted Answer

Bromocriptine

Answer

Reserpine

Answer

Acyclovir

Answer

Alpha methyl dopa

Question 6

The following drugs are used for prophylaxis of migraine except

Accepted Answer

Meperidine

Answer

Metoprolol

Answer

Valproate

Answer

Topiramate

Question 7

Drugs used for Prophylaxis of migraine include the following except?

Accepted Answer

Sumatriptan

Answer

Valproate

Answer

TCAs

Answer

Propranolol

Question 8

Nephrotoxic agent is:

Accepted Answer

Methoxyflurane

Answer

N2O

Answer

Halothane

Answer

Isoflurane

Question 9

Which of the following medications in the treatment of Parkinson's disease is an NMDA antagonist?

Accepted Answer

Amantadine

Answer

Selegiline

Answer

Entacapone

Answer

Ropinirole

Question 10

Modafinil is used for

Accepted Answer

Narcolepsy

Answer

Psychogenic erectile dysfunction

Answer

Orthostatic hypotension

Answer

OCD

Central Nervous System Pharmacology — MCQs

Central Nervous System Pharmacology — MCQs

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