Central Nervous System Pharmacology Practice Questions

Q: Which of the following is the shortest acting benzodiazepine?

Midazolam. ***Midazolam*** - **Midazolam** has a very short half-life (1.5-2.5 hours) and undergoes rapid metabolism, making it suitable for procedures needing **brief sedation** or inducing anesthesia. - Its quick onset and offset are due to its high lipid solubility and hepatic metabolism, leading to its prevalent use in **surgical and diagnostic settings**. *Alprazolam* - **Alprazolam** has an intermediate half-life (6-20 hours) and is commonly used for **anxiety disorders** and panic attacks. - While relatively fast-acting, its duration of action is significantly longer than Midazolam. *Chlordiazepoxide* - **Chlordiazepoxide** is a long-acting benzodiazepine with a half-life ranging from 5 to 30 hours, and its active metabolites can extend its effects even further. - It is often used for **alcohol withdrawal syndrome** and generalized anxiety. *Diazepam* - **Diazepam** is a long-acting benzodiazepine with a half-life of 20-100 hours, and its active metabolites (like desmethyldiazepam) have even longer half-lives. - It is used for conditions like **anxiety, muscle spasms, and seizures**, requiring prolonged therapeutic effects.

Q: Fingernail hypoplasia is a complication of which of the following drugs?

carbamazepine. ***Carbamazepine*** - **Fingernail hypoplasia** (underdevelopment of nails) is a known teratogenic effect associated with first-trimester exposure to **carbamazepine**, part of the **fetal anticonvulsant syndrome**. - Other features of this syndrome include characteristic facial dysmorphism, microcephaly, developmental delay, and skeletal abnormalities. *Risperidone* - Risperidone is an **atypical antipsychotic** and its primary teratogenic risks are related to neonatal adaptation syndrome, such as withdrawal symptoms, rather than structural defects like fingernail hypoplasia. - While all antipsychotics should be used with caution during pregnancy, specific associations with structural malformations are less common and less severe than with some antiepileptic drugs. *Lithium* - Lithium is associated with a specific cardiac malformation, **Ebstein's anomaly**, when taken during the first trimester of pregnancy. - It is not typically linked to limb or nail hypoplasia. *Olanzapine* - Olanzapine is another **atypical antipsychotic** whose use in pregnancy is primarily linked to risks like **gestational diabetes** and **neonatal withdrawal symptoms**. - There is no strong evidence linking olanzapine to structural malformations like fingernail hypoplasia.

Q: Donepezil is used in treatment of:

Alzheimer's dementia. ***Alzheimer's dementia*** - **Donepezil** is a **cholinesterase inhibitor** that increases the availability of **acetylcholine** in the brain, improving **cognitive function** in patients with Alzheimer's. - It is one of the primary medications approved for the symptomatic treatment of **mild to moderate** Alzheimer's disease. *Anxiety disorder* - **Anxiety disorders** are typically treated with **selective serotonin reuptake inhibitors (SSRIs)**, **benzodiazepines**, or psychotherapy. - Donepezil has no established role or efficacy in the treatment of anxiety disorders. *Schizophrenia* - **Schizophrenia** is managed with **antipsychotic medications** that primarily target **dopamine** and **serotonin** systems in the brain. - Donepezil's mechanism of action, increasing acetylcholine, is not relevant to the pathology or treatment of schizophrenia. *Parkinson's disease* - **Parkinson's disease** is primarily characterized by the degeneration of **dopaminergic neurons** and motor symptoms are treated with medications like **levodopa**. - While **rivastigmine** (another cholinesterase inhibitor) is approved for Parkinson's disease dementia, **donepezil** is specifically indicated for **Alzheimer's disease**, not Parkinson's disease.

Q: All of the following are Anticholinesterases used in Alzheimer's disease except

Memantine. ***Memantine*** - While used in Alzheimer's disease, **memantine** is an **NMDA receptor antagonist**, not an anticholinesterase. - It works by blocking excessive **glutamatergic stimulation**, which is implicated in neurodegeneration. *Donepezil* - **Donepezil** is an **acetylcholinesterase inhibitor** used to treat mild to moderate Alzheimer's disease. - It increases the availability of **acetylcholine** in the synaptic cleft, improving cognitive function. *Rivastigmine* - **Rivastigmine** is a **cholinesterase inhibitor** that acts on both **acetylcholinesterase** and **butyrylcholinesterase**. - It is approved for the treatment of mild to moderate Alzheimer's disease and Parkinson's disease dementia. *Galantamine* - **Galantamine** is an **acetylcholinesterase inhibitor** and an **allosteric potentiator of nicotinic acetylcholine receptors**. - It enhances cholinergic neurotransmission and is used in the treatment of mild to moderate Alzheimer's disease.

Q: All of the following can be used for prophylaxis of migraine except

Sumatriptan. ***Sumatriptan*** - Sumatriptan is a **triptan**, a class of drugs primarily used for the **acute treatment** of migraine attacks, not for prophylaxis. - It works by constricting intracranial blood vessels and inhibiting pro-inflammatory neuropeptide release. *Topiramate* - **Topiramate** is an **antiepileptic drug** commonly used for migraine prophylaxis, especially in patients with associated epilepsy. - Its mechanism of action involves various pathways, including modulation of **GABA** and **glutamate** receptors. *Valproate* - **Valproate** (Divalproex sodium) is another **antiepileptic drug** effective in preventing migraine headaches. - It works by increasing **GABA** levels in the brain and stabilizing neuronal membranes. *Propranolol* - **Propranolol** is a **beta-blocker** widely used for migraine prophylaxis, particularly in patients with co-occurring hypertension or anxiety. - It acts by preventing cerebral vasodilation and influencing central serotonergic pathways.

Q: All of the following are effective topically except-

Procaine. ***Procaine*** - **Procaine** is an ester-type local anesthetic with poor topical penetration due to its **chemical structure and low lipophilicity**. - It is primarily used for **infiltration anesthesia** and nerve blocks, requiring direct injection into tissues to achieve its local anesthetic effects. *Amethocaine* - **Amethocaine** (tetracaine) is a potent ester local anesthetic that is very effective for **topical anesthesia**, particularly on mucous membranes and the eye. - Its high lipophilicity allows for good absorption through the skin and mucous membranes, providing prolonged anesthetic effects. *Lidocaine* - **Lidocaine** is an amide-type local anesthetic that is widely used for **topical anesthesia** due to its excellent penetration and rapid onset of action. - It is available in various forms such as creams, gels, and patches for surface anesthesia. *Cocaine* - **Cocaine** is a naturally occurring ester local anesthetic that is highly effective topically, particularly on **mucous membranes** (e.g., nasal passages). - Besides its local anesthetic properties, it also causes **vasoconstriction**, which helps to reduce bleeding.

Q: Opioid antagonist that can be given orally –

Naltrexone. ***Naltrexone*** - **Naltrexone** is an opioid antagonist used for treating **opioid dependence** and alcohol dependence. - It has good oral bioavailability and is administered orally, typically as a daily dose. *Pentazocine* - **Pentazocine** is an opioid agonist-antagonist, primarily acting as an **agonist** at kappa opioid receptors and a weak antagonist or partial agonist at mu opioid receptors. - It is not a pure opioid antagonist and thus cannot reverse opioid effects effectively. *Naloxone* - **Naloxone** is a pure opioid antagonist primarily used to reverse **acute opioid overdose** due to its rapid onset and short duration of action. - While it can be given orally, it has very **low oral bioavailability** due to extensive first-pass metabolism, making it unsuitable for chronic oral administration. *Nalbuphine* - **Nalbuphine** is an opioid agonist-antagonist, similar to pentazocine, acting as an **agonist** at kappa opioid receptors and an antagonist at mu opioid receptors. - It is typically administered parenterally for pain relief and is not used as an oral opioid antagonist.

Q: Which of the following statements about EMLA is true?

Mixture of local anesthetics. ***Mixture of local anesthetics*** - **EMLA** (Eutectic Mixture of Local Anesthetics) is a cream composed of a 1:1 mixture of **lidocaine** and **prilocaine**. - This eutectic mixture has a lower melting point than its individual components, allowing it to penetrate the skin more effectively for **topical anesthesia**. *Can be used for intubation* - EMLA is a **topical anesthetic cream** designed for skin surface application rather than mucosal surfaces or deep tissue. - Its slow onset and limited depth of penetration make it **unsuitable for intubation**, which requires rapid and profound anesthesia of the airway. *Faster acting* - EMLA requires an application time of **at least 60 minutes** (and sometimes longer for deeper anesthesia) to achieve maximal effect. - This **slow onset** is a significant limitation and is much slower than injected local anesthetics or other rapid-acting topical agents. *Used only in children* - EMLA is indeed **commonly used in children** to reduce pain from venipuncture, vaccinations, and minor procedures. - However, it is also widely used in **adults** for similar indications, such as before IV insertions, laser treatments, or skin biopsies.

Q: A young male, Farhan, suffers from a seizure disorder which is characterized by tonic rigidity of limbs followed in 20-30 seconds by tremors progressing to massive jerking of the body. This clonic phase lasts for 1-3 minutes. The anti-seizure drug of choice for this patient is:

Valproic acid. ***Valproic acid***\n- The description of tonic rigidity followed by tremors and massive jerking of the body is characteristic of a **generalized tonic-clonic seizure (GTCS)** [1], [2].\n- **Valproic acid** is a **broad-spectrum antiepileptic drug** and is considered the **drug of choice** for GTCS due to its efficacy across multiple seizure types and favorable profile for long-term management [1].\n- It is the **most commonly recommended first-line agent** for newly diagnosed GTCS in most clinical guidelines [1].\n\n*Clonazepam*\n- **Clonazepam** is a benzodiazepine primarily used for absence seizures, myoclonic seizures, and status epilepticus [1].\n- While it has broad anti-seizure activity, it is **not first-line monotherapy** for long-term management of GTCS due to concerns about **tolerance, dependence, and sedation** [1].\n\n*Ethosuximide*\n- **Ethosuximide** is **specifically indicated only for absence seizures** (petit mal seizures).\n- It has **no efficacy against tonic-clonic seizures** and would be completely inappropriate for this patient.\n\n*Fosphenytoin*\n- **Fosphenytoin** is a prodrug of phenytoin and is an effective treatment for generalized tonic-clonic seizures [1].\n- While phenytoin/fosphenytoin is a valid first-line option for GTCS, **valproic acid is generally preferred** as the drug of choice due to its **broader spectrum of activity**, better tolerability profile, and effectiveness across more seizure types [1].\n- Fosphenytoin is commonly used in both acute management (status epilepticus) and chronic therapy, but requires monitoring for side effects like gingival hyperplasia, hirsutism, and drug interactions.

Q: All of the following drugs are used in prophylaxis of migraine, except

Levetiracetam. ***Levetiracetam*** - **Levetiracetam** is an antiepileptic drug primarily used for the treatment of seizures. - It is **not indicated** or commonly used for the prophylaxis of migraine. *Propranolol* - **Propranolol** is a non-selective beta-blocker that is a well-established and effective medication for migraine prophylaxis. - It helps reduce the frequency and severity of migraine attacks. *Topiramate* - **Topiramate** is an antiepileptic drug that is also approved and widely used for migraine prophylaxis. - Its mechanism of action in migraine prevention includes modulating neurotransmitters and ion channels. *Flunarizine* - **Flunarizine** is a calcium channel blocker commonly used for migraine prophylaxis, especially in Europe and other regions. - It helps stabilize vascular tone and neuronal excitability, reducing migraine frequency.

Question 1

Which of the following is the shortest acting benzodiazepine?

Accepted Answer

Midazolam

Answer

Alprazolam

Answer

Chlordiazepoxide

Answer

Diazepam

Question 2

Fingernail hypoplasia is a complication of which of the following drugs?

Accepted Answer

carbamazepine

Answer

risperidone

Answer

lithium

Answer

olanzapine

Question 3

Donepezil is used in treatment of:

Accepted Answer

Alzheimer's dementia

Answer

Anxiety disorder

Answer

Schizophrenia

Answer

Parkinson's disease

Question 4

All of the following are Anticholinesterases used in Alzheimer's disease except

Accepted Answer

Memantine

Answer

Donepezil

Answer

Rivastigmine

Answer

Galantamine

Question 5

All of the following can be used for prophylaxis of migraine except

Accepted Answer

Sumatriptan

Answer

Topiramate

Answer

Valproate

Answer

Propranolol

Question 6

All of the following are effective topically except-

Accepted Answer

Procaine

Answer

Amethocaine

Answer

Lidocaine

Answer

Cocaine

Question 7

Opioid antagonist that can be given orally –

Accepted Answer

Naltrexone

Answer

Pentazocine

Answer

Naloxone

Answer

Nalbuphine

Question 8

Which of the following statements about EMLA is true?

Accepted Answer

Mixture of local anesthetics

Answer

Can be used for intubation

Answer

Faster acting

Answer

Used only in children

Question 9

A young male, Farhan, suffers from a seizure disorder which is characterized by tonic rigidity of limbs followed in 20-30 seconds by tremors progressing to massive jerking of the body. This clonic phase lasts for 1-3 minutes. The anti-seizure drug of choice for this patient is:

Accepted Answer

Valproic acid

Answer

Clonazepam

Answer

Ethosuximide

Answer

Fosphenytoin

Question 10

All of the following drugs are used in prophylaxis of migraine, except

Accepted Answer

Levetiracetam

Answer

Propranolol

Answer

Topiramate

Answer

Flunarizine

Central Nervous System Pharmacology — MCQs

Central Nervous System Pharmacology — MCQs

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