Mood Stabilizers — MCQs
A patient with depression was given Imipramine for 2 weeks. Relatives noticed increased excitement, colorful clothes, and increased talking. What is the next step in management?
Which anti-epileptic drug is most likely to cause aplastic anemia?
A patient on lithium therapy developed hypertension and was started on a thiazide diuretic. After a few days, he developed coarse tremors and other symptoms suggestive of lithium toxicity. What is the probable mechanism of interaction between thiazide diuretics and lithium?
Which of the following statements about lamotrigine is correct?
A patient is on warfarin therapy. All of the following drugs increase the risk of bleeding with warfarin except?
Which of the following antidepressant drugs is used in the treatment of nocturnal enuresis?
Which of the following is excreted in saliva?
Drugs used for Prophylaxis of migraine include the following except?
A patient presents with painful oral ulcers and target lesions on extremities. Which drug is MOST likely to cause this condition?
A 6-year-old child has poor school performance. On scolding by teacher abnormal behavior is noted. EEG is performed. Which of the following drugs will cause worsening of the patient?
Mood Stabilizers Indian Medical PG Practice Questions and MCQs
Question 1: A patient with depression was given Imipramine for 2 weeks. Relatives noticed increased excitement, colorful clothes, and increased talking. What is the next step in management?
- A. Continue Imipramine alone
- B. Manage with Valproate alone
- C. Discontinue Imipramine and start Valproate (Correct Answer)
- D. Antipsychotic with Imipramine continued
Explanation: ***Discontinue Imipramine and start Valproate*** - The patient's symptoms (increased excitement, colorful clothes, increased talking) after starting an antidepressant like **Imipramine** suggest a **manic switch**, indicating undiagnosed **bipolar disorder**. - **Imipramine** should be discontinued as it can exacerbate mania, and a mood stabilizer like **Valproate** is necessary to treat the manic episode. *Continue Imipramine alone* - Continuing Imipramine would likely worsen the manic symptoms, leading to increased agitation and potential harm. - Antidepressants can trigger or worsen manic episodes in individuals with underlying bipolar disorder. *Manage with Valproate alone* - While Valproate is an appropriate treatment for acute mania, simply managing with Valproate alone without discontinuing the offending antidepressant would be suboptimal. - The continued presence of Imipramine would counteract the mood-stabilizing effects of Valproate. *Antipsychotic with Imipramine continued* - Adding an antipsychotic might manage some acute manic symptoms, but continuing Imipramine would maintain the driving force behind the manic switch. - The primary action should be to remove the causative agent (Imipramine) and replace it with a mood stabilizer.
Question 2: Which anti-epileptic drug is most likely to cause aplastic anemia?
- A. Phenytoin
- B. Carbamazepine (Correct Answer)
- C. Levetiracetam
- D. Valproate
Explanation: ***Carbamazepine*** - **Carbamazepine** is an anti-epileptic drug that can cause **aplastic anemia** as a rare but serious adverse effect. It is also known to cause other hematological side effects like leukopenia and thrombocytopenia. - Regular monitoring of **complete blood counts** is recommended, especially during the initial phases of treatment, due to this risk. *Phenytoin* - While **phenytoin** can cause various adverse effects, including **folate deficiency** leading to megaloblastic anemia, it is not typically associated with **aplastic anemia**. - Other common side effects include gingival hyperplasia, hirsutism, and Stevens-Johnson syndrome. *Levetiracetam* - **Levetiracetam** is generally well-tolerated and is rarely associated with severe hematological adverse events like **aplastic anemia**. - Its most common side effects are somnolence, asthenia, and behavioral changes. *Valproate* - **Valproate** can cause **thrombocytopenia** and, in rare instances, bone marrow suppression, but it is not a primary cause of **aplastic anemia**. - Its most concerning adverse effects include hepatotoxicity and pancreatitis.
Question 3: A patient on lithium therapy developed hypertension and was started on a thiazide diuretic. After a few days, he developed coarse tremors and other symptoms suggestive of lithium toxicity. What is the probable mechanism of interaction between thiazide diuretics and lithium?
- A. Thiazide increases the tubular reabsorption of lithium (Correct Answer)
- B. Thiazide inhibits the metabolism of lithium
- C. Thiazides act as an add-on drug to lithium
- D. None of the above
Explanation: ***Thiazide increases the tubular reabsorption of lithium*** - Thiazide diuretics cause a decrease in sodium reabsorption in the distal convoluted tubule, leading to increased sodium excretion in urine. - The kidneys, in an attempt to conserve sodium, increase reabsorption in the proximal tubule. Because **lithium** is reabsorbed similarly to sodium in the proximal tubule, this increased reabsorption also affects lithium, leading to a rise in its plasma concentration and toxicity. *Thiazide inhibits the metabolism of lithium* - Lithium is primarily excreted by the kidneys and is not significantly metabolized in the body. - Thiazide diuretics do not affect enzyme systems responsible for drug metabolism. *Thiazides act as an add on the drug to lithium* - This statement is vague and does not explain a mechanism of interaction leading to toxicity. - While both drugs might be prescribed concurrently for different conditions, "add on" does not describe a pharmacological interaction causing altered drug levels. *None of the above* - This option is incorrect because a clear and well-understood mechanism for the interaction between thiazide diuretics and lithium exists.
Question 4: Which of the following statements about lamotrigine is correct?
- A. Is the first choice for absence seizures.
- B. Has a half-life of approximately 24 hours. (Correct Answer)
- C. Is not significantly metabolized in the liver.
- D. Has decreased efficacy in treating depressive episodes.
Explanation: ***Has a half-life of approximately 24 hours.*** - Lamotrigine's **half-life** is typically around **24 to 33 hours** in adults, which allows for once or twice-daily dosing. - This relatively long half-life is advantageous for maintaining **stable plasma concentrations** and improving patient adherence. *Is the first choice for absence seizures.* - **Ethosuximide** or **valproate** are generally considered first-line treatments for **absence seizures**. - Lamotrigine is not the preferred initial therapy due to its **slower titration** and occasional lack of efficacy in this seizure type. *Is not significantly metabolized in the liver.* - Lamotrigine is **significantly metabolized** in the liver, primarily through **glucuronidation** by the **UGT1A4 enzyme**. - This hepatic metabolism explains many of its **drug interactions**, particularly with other antiepileptic drugs affecting UGT enzymes. *Has decreased efficacy in treating depressive episodes.* - Lamotrigine is known for its **mood-stabilizing properties** and is effective in treating and preventing **depressive episodes**, particularly in **bipolar disorder**. - Its efficacy in depression is a key distinguishing feature, making it a valuable option for patients with comorbid mood disorders.
Question 5: A patient is on warfarin therapy. All of the following drugs increase the risk of bleeding with warfarin except?
- A. Isoniazid
- B. Amiodarone
- C. Carbamazepine (Correct Answer)
- D. Cimetidine
Explanation: ***Carbamazepine*** - Carbamazepine **induces cytochrome P450 enzymes**, specifically **CYP3A4** and **CYP2C9**, which are responsible for warfarin metabolism. - This induction leads to a **faster metabolism of warfarin**, thus **decreasing its anticoagulant effect** and thereby reducing the risk of bleeding. *Isoniazid* - Isoniazid is an **inhibitor of cytochrome P450 enzymes**, primarily **CYP2C9**, which metabolizes the more potent S-warfarin isomer. - This inhibition **decreases warfarin metabolism**, leading to **increased anticoagulant effect** and higher risk of bleeding. *Amiodarone* - Amiodarone is a potent **inhibitor of cytochrome P450 enzymes**, significantly **CYP2C9** and **CYP3A4**. - It leads to a **reduced metabolism of warfarin**, causing **elevated INR** and an increased risk of bleeding. *Cimetidine* - Cimetidine is a known **inhibitor of various cytochrome P450 enzymes**, particularly **CYP1A2**, **CYP2C9**, and **CYP3A4**. - Its inhibitory action on warfarin metabolism results in **higher warfarin levels** and an **increased risk of bleeding**.
Question 6: Which of the following antidepressant drugs is used in the treatment of nocturnal enuresis?
- A. Imipramine (Correct Answer)
- B. Fluoxetine
- C. Trazodone
- D. Sertraline
Explanation: ***Imipramine*** - **Imipramine**, a **tricyclic antidepressant (TCA)**, is effective in treating nocturnal enuresis, particularly in children. - Its mechanism of action in this context is thought to involve anticholinergic effects, leading to **increased bladder capacity**, and alpha-adrenergic effects, causing **contraction of the internal urethral sphincter**. *Fluoxetine* - **Fluoxetine** is a **selective serotonin reuptake inhibitor (SSRI)** primarily used to treat depression, anxiety disorders, and obsessive-compulsive disorder. - It does not have a primary indication or established efficacy for the treatment of nocturnal enuresis. *Trazodone* - **Trazodone** is an **antidepressant** with sedative properties, often used for insomnia and depression. - While it modulates serotonin, it is not a first-line or established treatment for nocturnal enuresis. *Sertraline* - **Sertraline** is another **selective serotonin reuptake inhibitor (SSRI)** commonly prescribed for depression, anxiety, and panic disorder. - Like other SSRIs, it is not indicated for and has no significant role in the management of nocturnal enuresis.
Question 7: Which of the following is excreted in saliva?
- A. Lithium (Correct Answer)
- B. Chloramphenicol
- C. Ampicillin
- D. Tetracycline
Explanation: ***Lithium*** - **Lithium** is actively excreted in saliva, making salivary lithium levels a potential, though not routinely used, indicator of serum levels. - The salivary glands can concentrate lithium, leading to concentrations in saliva that are typically **2 to 3 times higher** than in plasma (saliva/plasma ratio of approximately 2-3:1). - This property makes saliva a useful non-invasive medium for therapeutic drug monitoring of lithium. *Chloramphenicol* - **Chloramphenicol** is primarily metabolized in the liver by glucuronidation and excreted in the urine. - While small amounts may be found in various body fluids, it is not a significant component of salivary excretion. *Ampicillin* - **Ampicillin**, a penicillin antibiotic, is mainly eliminated unchanged via renal excretion. - Salivary excretion is not a primary route of elimination for ampicillin. *Tetracycline* - **Tetracycline** antibiotics are primarily excreted unchanged by the kidneys and, to a lesser extent, in bile. - While some drugs can be detected in saliva, tetracycline is not notably excreted through this route in clinically significant amounts.
Question 8: Drugs used for Prophylaxis of migraine include the following except?
- A. Valproate
- B. Sumatriptan (Correct Answer)
- C. TCAs
- D. Propranolol
Explanation: ***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.
Question 9: A patient presents with painful oral ulcers and target lesions on extremities. Which drug is MOST likely to cause this condition?
- A. Metformin
- B. Allopurinol (Correct Answer)
- C. Atorvastatin
- D. Amlodipine
Explanation: ***Allopurinol*** - **Allopurinol** is a well-known cause of drug-induced **Stevens-Johnson Syndrome (SJS)** or **Toxic Epidermal Necrolysis (TEN)**, which presents with typical mucocutaneous lesions like painful oral ulcers and target lesions on the skin. - The drug is frequently implicated, especially in patients with **renal impairment** or those started on high doses, making it the most likely choice given the severe symptoms. *Metformin* - **Metformin** is a common medication for type 2 diabetes, primarily causing **gastrointestinal side effects** like nausea, diarrhea, and abdominal discomfort. - It is **rarely associated** with severe cutaneous adverse reactions like SJS/TEN. *Atorvastatin* - **Atorvastatin** is a statin commonly used for hyperlipidemia, and its most common side effects include **myalgia**, headache, and gastrointestinal issues. - While it can rarely cause *rashes*, it is **not a typical or frequent cause** of severe mucocutaneous reactions such as target lesions or painful oral ulcers characteristic of SJS/TEN. *Amlodipine* - **Amlodipine**, a calcium channel blocker, is typically associated with side effects such as **edema**, headache, and flushing. - Although drug eruptions can occur with amlodipine, **severe mucocutaneous reactions** like SJS/TEN presenting with target lesions and oral ulcers are **exceedingly rare** and not characteristic of this drug.
Question 10: A 6-year-old child has poor school performance. On scolding by teacher abnormal behavior is noted. EEG is performed. Which of the following drugs will cause worsening of the patient?
- A. Ethosuximide
- B. Valproate
- C. Carbamazepine (Correct Answer)
- D. Clonazepam
Explanation: ***Carbamazepine*** - The EEG image shows **generalized spike-wave complexes at 3 Hz**, which are characteristic of **absence seizures** (also known as petit mal seizures). - **Carbamazepine** is known to **exacerbate absence seizures** and should be avoided in patients with this diagnosis. *Ethosuximide* - This is a **first-line drug** specifically for treating **absence seizures**. - It works by blocking **T-type calcium channels** in the thalamus, effectively reducing spike-wave discharges. *Valproate* - **Valproate** is a broad-spectrum anticonvulsant effective against various seizure types, including **absence seizures**, generalized tonic-clonic seizures, and myoclonic seizures. - It is an appropriate choice if ethosuximide is ineffective or if other seizure types coexist. *Clonazepam* - **Clonazepam** is a **benzodiazepine** that can be used as an add-on therapy for **absence seizures**, especially in refractory cases. - While it has sedative side effects, it does not typically worsen absence seizures; rather, it helps control them.
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