Drugs in Psychiatric Disorders Practice Questions

Q: A 40-year-old patient with refractory epilepsy is on a multi-drug antiepileptic regimen. Two weeks after a dosage adjustment, he develops diffuse morbilliform rash, fever and oral mucosal erosions. Which of the following antiepileptic drugs can most saf ely be continued?

Clobazam. ***Clobazam*** - Clobazam is a **benzodiazepine** that acts as a positive allosteric modulator of GABA-A receptors, which is structurally distinct from traditional aromatic antiepileptic drugs (AEDs) like phenytoin or lamotrigine. - It is not associated with the **hypersensitivity reactions** (like DRESS syndrome or SJS/TEN) commonly triggered by the aromatic AEDs involved in the patient's current regimen. *Phenytoin* - Phenytoin is a known culprit for drug-induced **hypersensitivity reactions** (DRESS syndrome) due to its metabolites (arene oxides) that cause immune dysregulation. - It is strictly contraindicated in patients presenting with **morbilliform rashes** and systemic symptoms like fever and mucosal involvement, as continuation can lead to fatal complications. *Valproate* - Valproate is an aliphatic AED, but it can contribute to **DRESS syndrome** and also causes **hepatotoxicity**, which exacerbates the patient's systemic inflammatory response. - It is generally advised to discontinue implicated agents in a multidrug regimen to stabilize the patient, making it an unsafe drug to continue in this clinical context. *Lamotrigine* - Lamotrigine has a high potential for causing **severe cutaneous adverse reactions (SCARs)** such as **Stevens-Johnson Syndrome (SJS)** and **Toxic Epidermal Necrolysis (TEN)**, especially when titrated rapidly. - Given the presence of **oral mucosal erosions**, this drug is a highly suspicious trigger and must be discontinued immediately to prevent further progression.

Q: Which of the following ECG change is most characteristically associated with lithium therapy?

T-wave inversion. ***T-wave inversion*** - **Lithium** therapy is well-recognized for causing benign and reversible ECG changes, most characteristically **T-wave flattening or inversion**. - These changes are generally considered **non-specific** and typically do not require discontinuation of the medication unless associated with clinical cardiac symptoms or toxicity. *ST-segment elevation* - **ST-segment elevation** is much more characteristic of conditions like **acute myocardial infarction** or **pericarditis**, not lithium use. - It is not a common side effect of mood stabilizers and would necessitate a thorough investigation for **ischemic heart disease**. *ST-segment depression* - **ST-segment depression** is a classic sign of **myocardial ischemia** or **digoxin toxicity**. - This finding is not associated with lithium therapy and would indicate a different underlying pathology requiring separate investigation. *QT interval prolongation* - While **QT interval prolongation** is a serious adverse effect of many antipsychotic medications and antidepressants, it is not the primary ECG change associated with **lithium**. - Prolongation of the **QT interval** poses a risk for **torsades de pointes**, and its absence is a distinguishing feature of lithium compared to many other psychotropic agents.

Q: Which of the following drugs has the highest potential to cause metabolic syndrome?

Clozapine. **Explanation:** Metabolic syndrome—characterized by significant weight gain, hyperlipidemia, and hyperglycemia (Type 2 Diabetes)—is a major adverse effect of **Second-Generation Antipsychotics (SGAs)**. **1. Why Clozapine is correct:** Clozapine (along with Olanzapine) carries the **highest risk** of metabolic syndrome. The underlying mechanism involves potent antagonism of **H1 (histamine)** and **5-HT2C (serotonin)** receptors, which leads to increased appetite, sedation, and direct interference with insulin sensitivity. Clozapine is associated with the most profound weight gain and the highest incidence of new-onset diabetes among all antipsychotics. **2. Analysis of incorrect options:** * **Quetiapine:** Also carries a high risk of metabolic syndrome, but it is clinically ranked lower than Clozapine and Olanzapine. * **Risperidone:** Carries a moderate risk. It is more notorious for causing hyperprolactinemia (due to D2 blockade in the tuberoinfundibular pathway) than severe metabolic derangement. * **Aripiprazole:** This is a partial D2 agonist and has the **lowest risk** (metabolically neutral) along with Ziprasidone and Lurasidone. **3. NEET-PG High-Yield Pearls:** * **Hierarchy of Metabolic Risk:** Clozapine = Olanzapine > Quetiapine > Risperidone > Aripiprazole = Ziprasidone. * **Monitoring:** Patients on Clozapine require mandatory monitoring of BMI, fasting blood glucose, and lipid profiles. * **Clozapine "Must-Knows":** It is the drug of choice for **resistant schizophrenia**, but its use is limited by **agranulocytosis** (requires regular CBC monitoring) and a lowered seizure threshold.

Q: Which drug can cause psychosis?

Amfetamine. ### Explanation **Correct Option: B. Amfetamine** Amfetamine is a potent CNS stimulant that acts primarily by increasing the release of biogenic amines, particularly **Dopamine**, from presynaptic nerve terminals. According to the **Dopamine Hypothesis of Schizophrenia**, excessive dopaminergic activity in the mesolimbic pathway is linked to psychotic symptoms. High doses or chronic use of amfetamines can induce a "stimulant psychosis" that clinically mimics paranoid schizophrenia, characterized by delusions, hallucinations, and stereotypic behavior. **Analysis of Incorrect Options:** * **A. Ofloxacin:** While fluoroquinolones can occasionally cause CNS side effects like insomnia or dizziness, they are not classically associated with inducing frank psychosis. * **C. Capreomycin:** This is a polypeptide protein synthesis inhibitor used in MDR-TB. Its primary toxicities are **nephrotoxicity** and **ototoxicity** (8th cranial nerve damage), similar to aminoglycosides. * **D. Rifampicin:** A key anti-tubercular drug known for causing orange-colored secretions (urine, sweat, tears) and hepatotoxicity. It does not have psychotropic side effects. **High-Yield Clinical Pearls for NEET-PG:** * **Other drugs causing psychosis:** Levodopa (dopamine precursor), Steroids ("Steroid Psychosis"), Isoniazid (INH), Ketamine, and Cocaine. * **Drug of Choice for Amfetamine Psychosis:** Antipsychotics like **Haloperidol** (D2 blockers) are used to manage acute symptoms. * **Mechanism Recap:** Amfetamines reverse the direction of the dopamine transporter (DAT), pumping dopamine out into the synapse.

Q: Which is the recently approved drug for psychosis associated with Parkinsonism?

Pimavanserin. **Explanation:** **Pimavanserin** is the correct answer. It is a novel atypical antipsychotic specifically FDA-approved for the treatment of hallucinations and delusions associated with **Parkinson’s Disease Psychosis (PDP)**. **Mechanism of Action:** Unlike traditional antipsychotics that block Dopamine (D2) receptors—which would worsen motor symptoms in Parkinson’s—Pimavanserin acts as a **selective inverse agonist and antagonist at 5-HT2A receptors**. It has no significant affinity for D2, muscarinic, or histaminergic receptors. This allows it to treat psychotic symptoms without deteriorating motor function. **Analysis of Incorrect Options:** * **A. Lorcaserin:** A selective 5-HT2C receptor agonist previously used for weight loss (withdrawn from many markets due to safety concerns); it has no role in psychosis. * **C. Cycloserine:** An antitubercular drug (second-line) that also acts as a partial NMDA receptor agonist; it is not used for Parkinsonian psychosis. * **D. Mianserin:** A tetracyclic antidepressant that blocks alpha-2 adrenergic and 5-HT receptors; while it has sedative properties, it is not the indicated treatment for PDP. **Clinical Pearls for NEET-PG:** * **Drug of Choice for PDP:** Pimavanserin is preferred. If unavailable, **Quetiapine** or **Clozapine** (at low doses) are the traditional alternatives because they have the lowest D2 affinity among standard antipsychotics. * **Avoid:** Typical antipsychotics (e.g., Haloperidol) and certain atypicals (e.g., Risperidone) as they severely worsen Parkinsonian tremors and rigidity. * **Side Effects:** Pimavanserin can cause QT interval prolongation; monitor patients with pre-existing cardiac conditions.

Question 1

A 40-year-old patient with refractory epilepsy is on a multi-drug antiepileptic regimen. Two weeks after a dosage adjustment, he develops diffuse morbilliform rash, fever and oral mucosal erosions. Which of the following antiepileptic drugs can most saf ely be continued?

Accepted Answer

Clobazam

Answer

Phenytoin

Answer

Valproate

Answer

Lamotrigine

Question 2

Which of the following ECG change is most characteristically associated with lithium therapy?

Accepted Answer

T-wave inversion

Answer

ST-segment elevation

Answer

ST-segment depression

Answer

QT interval prolongation

Question 3

Which of the following drugs has the highest potential to cause metabolic syndrome?

Accepted Answer

Clozapine

Answer

Risperidone

Answer

Quetiapine

Answer

Aripiprazole

Question 4

Which drug can cause psychosis?

Accepted Answer

Amfetamine

Answer

Ofloxacin

Answer

Capreomycin

Answer

Rifampicin

Question 5

Which is the recently approved drug for psychosis associated with Parkinsonism?

Accepted Answer

Pimavanserin

Answer

Lorcaserin

Answer

Cycloserine

Answer

Mianserin

Drugs in Psychiatric Disorders — MCQs

Drugs in Psychiatric Disorders — MCQs

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