Clinical Pharmacology and Drug Toxicity Practice Questions

Q: A 25-year-old woman presents to the emergency department 6 hours after ingesting a large quantity of paracetamol tablets. What is the most likely progression of paracetamol poisoning in this case?

Increase in liver enzymes starting around 24 hours. ***Increase in liver enzymes starting around 24 hours*** - Phase 2 of paracetamol toxicity, occurring **24–72 hours post-ingestion**, is characterized by the onset of **hepatotoxicity**, marked by rising **AST** and **ALT** levels. - The patient is currently 6 hours post-ingestion (late Phase 1), so the most likely progression is entering Phase 2, where biochemical evidence of liver damage begins around 24 hours and continues to rise. *Liver failure within 24 hours* - **Acute liver failure** (manifested by coagulopathy, jaundice, and encephalopathy) typically develops around 3 to 4 days (72–96 hours) post-ingestion (Phase 3). - Within the first 24 hours, symptoms are usually mild or absent (Phase 1: nausea, vomiting, or asymptomatic). *Paracetamol achieves peak concentration within 4 hours* - While **peak plasma concentration** for standard paracetamol typically occurs around 4 hours post-ingestion, this pharmacokinetic event has already occurred since the patient presents at 6 hours. - The question asks for the subsequent toxicological *progression* (clinical course), not a past pharmacokinetic event. *Recovery within 72 hours* - Recovery (Phase 4) typically occurs after the peak injury period (around 4 days or later), especially with effective antidote treatment (**N-acetylcysteine**). - Given the ingestion of a **large quantity**, the patient is expected to progress through Phase 2 (**hepatotoxicity** at 24-72 hours) and possibly Phase 3 (peak toxicity at 72-96 hours), not recover within 72 hours.

Q: A 50-year-old factory worker was brought to the emergency room with complaints of headache, vomiting, and blurring of vision after he consumed local spirit. Which of the following is used for the treatment of his condition?

Fomepizole. ***Fomepizole***- Fomepizole is the preferred antidote for **methanol** and **ethylene glycol** poisoning because it competitively inhibits the enzyme **alcohol dehydrogenase** (ADH).- By inhibiting ADH, it prevents the metabolism of methanol into its toxic metabolite, **formic acid**, which is responsible for the characteristic **ocular toxicity** (blurring of vision) and **metabolic acidosis** seen in this patient.*Flumazenil*- Flumazenil is a competitive antagonist used to reverse the effects of **benzodiazepines**, primarily in cases of overdose or to reverse procedural sedation.- It has no role in the treatment of **methanol poisoning**, which causes toxicity via the accumulation of **formic acid**.*N-acetyl cysteine*- **N-acetyl cysteine (NAC)** is the specific antidote for **acetaminophen** (paracetamol) overdose, as it replenishes **glutathione** stores in the liver.- It is ineffective in the treatment of **methanol poisoning**, which requires ADH inhibition or **hemodialysis** to remove the toxins.*Naloxone*- **Naloxone** is an opioid antagonist used specifically to rapidly reverse the effects of **opioid overdose** by competing for the opioid receptors.- The patient's symptoms (headache, vomiting, blurring of vision) are classic for **methanol toxicity** and are not indicative of opioid overdose.

Q: Which of the following is a non-narcotic active principle of the opium poppy shown in the image below?

Noscapine. ***Noscapine*** - Noscapine is an **isoquinoline alkaloid** derived from the **opium poppy** (Papaver somniferum), which is depicted in the image. - It is a **non-narcotic antitussive** (cough suppressant) agent, meaning it does not have significant analgesic properties or potential for abuse typical of narcotics. *Morphine* - Morphine is a potent **narcotic analgesic** and the **most abundant opioid alkaloid** found in opium. - It works by binding to **opioid receptors** in the central nervous system, leading to pain relief, euphoria, and respiratory depression. *Codeine* - Codeine is another **narcotic opioid** derived from the opium poppy, known for its analgesic and antitussive effects. - It is a **prodrug** that is metabolized to morphine in the liver by the CYP2D6 enzyme, contributing to its opioid effects. *Thebaine* - Thebaine is an **opioid alkaloid** found in opium, but unlike morphine and codeine, it has little therapeutic use as an analgesic. - It is primarily used as a precursor in the industrial synthesis of other opioids, such as **oxycodone** and **naloxone**.

Q: The toxin shown below will cause:

Gangrene of fingers and toes. ***Gangrene of fingers and toes*** - The image displays **ergot sclerotia** (dark, elongated structures) growing on a grain stalk, which produce **ergot alkaloids**. - **Ergotism**, caused by ingestion of these alkaloids, leads to intense **vasoconstriction**, resulting in **ischemia** and eventually **gangrene** of the extremities, classically fingers and toes. *Opisthotonus* - **Opisthotonus** is a severe hyperextension and spasticity of the head, neck, and spinal column. - It is typically associated with conditions like **tetanus** or severe brain injury, not ergot poisoning. *DIC* - **Disseminated Intravascular Coagulation (DIC)** is a disorder characterized by systemic activation of blood coagulation, leading to microthrombi formation and consumption of clotting factors and platelets. - While various toxins can induce DIC, **ergot alkaloids** primarily cause vasoconstriction and ischemic tissue damage, rather than widespread coagulation imbalance directly. *Lock jaw* - **Lockjaw** or **trismus** is a sustained spasm of the masticatory muscles, preventing the mouth from opening. - This is a classic symptom of **tetanus**, caused by the neurotoxin **tetanospasmin**, not ergot alkaloids.

Q: Which of the following drugs taken by the mother during pregnancy can cause the congenital defect shown in the image?

Retinoic acid. ***Retinoic acid*** - The image depicts a severe **cleft lip and palate**, a common and well-documented teratogenic effect of **retinoids**, especially **isotretinoin (13-cis-retinoic acid)**, when taken during pregnancy. - Retinoic acid is an active metabolite of **vitamin A** and has critical roles in **embryonic development**; however, its excess can disrupt normal craniofacial development. *Folic acid* - **Folic acid** supplementation during pregnancy is protective and prevents **neural tube defects** (e.g., spina bifida, anencephaly), not associated with causing cleft lip or palate. - Adequate folic acid intake is recommended before and during early pregnancy to prevent neural tube defects. *Niacin* - **Niacin (vitamin B3)** supplementation in standard doses has not been directly implicated in causing cleft lip and palate. - Severe niacin deficiency can lead to **pellagra**, but this is not related to the craniofacial malformation shown. *Thiamine* - **Thiamine (vitamin B1)** supplementation is safe during pregnancy and not associated with teratogenic effects. - Thiamine deficiency can lead to **beriberi**, affecting the cardiovascular or nervous systems, but there is no established link between thiamine and cleft lip and palate.

Q: The condition shown in the image can be seen with all of the following EXCEPT:

Flupirtine. The image displays severe **gingival hypertrophy**, characterized by an overgrowth of gum tissue that covers a significant portion of the teeth. ***Flupirtine*** - **Flupirtine** is a centrally acting non-opioid analgesic that is not associated with gingival hypertrophy. - Its adverse effects are primarily related to neurological and hepatic systems, such as **dizziness**, **nausea**, and **liver enzyme elevation**. *M4 AML* - **Acute Myeloid Leukemia (AML) M4 subtype**, also known as acute myelomonocytic leukemia, is frequently associated with **gingival infiltration** and hypertrophy due to the proliferation of leukemic cells. - This infiltrative process can cause significant gingival enlargement, sometimes leading to tooth displacement and difficulty with oral hygiene. *Cyclosporine* - **Cyclosporine** is an immunosuppressant commonly used in organ transplantation and autoimmune diseases, and it is a well-known cause of drug-induced gingival hypertrophy. - The mechanism involves increased collagen synthesis and reduced collagen degradation in the gingival connective tissue. *Nifedipine* - **Nifedipine** is a calcium channel blocker used to treat hypertension and angina, and it is another common medication that causes drug-induced gingival hypertrophy. - The exact mechanism is not fully understood but is thought to involve altered fibroblast activity and collagen accumulation in the gingiva.

Q: A 6-year-old child was having multiple vomiting episodes after eating at mid-day meal scheme in school. The Doctor at PHC gave injectable anti-emetics after which the child developed following posturing. What is the clinical diagnosis and what drug should be given to counteract this posturing?

Oculogyric spasm, promethazine. ***Oculogyric spasm, promethazine*** - The image shows upward deviation of the eyes, known as an **oculogyric spasm**, a form of **acute dystonia**. This is a common extrapyramidal symptom (EPS) caused by dopamine receptor blocking antiemetics (e.g., metoclopramide, prochlorperazine) or antipsychotics. - **Promethazine**, an antihistamine with anticholinergic properties, or other anticholinergics like **benztropine** or **diphenhydramine**, are effective in treating acute dystonias by restoring the dopamine-acetylcholine balance in the basal ganglia. *Tardive dyskinesia, benztropine* - **Tardive dyskinesia** presents with involuntary, repetitive, and often bizarre movements (e.g., lip smacking, tongue protrusion), typically developing after chronic exposure to dopamine-blocking agents, not acutely. - While benztropine can treat some EPS, it is **not the primary treatment for tardive dyskinesia**, which often requires different management strategies, including switching medications or using VMAT2 inhibitors. *Malignant neuroleptic syndrome, dantrolene* - **Neuroleptic malignant syndrome (NMS)** is a severe, life-threatening reaction characterized by rigidity, fever, altered mental status, and autonomic instability. This differs from the isolated oculogyric spasm observed. - **Dantrolene** is used to treat the muscle rigidity and hyperthermia in NMS, along with bromocriptine for dopamine activity, but is not indicated for acute dystonia. *Akathisia, propranolol* - **Akathisia** is an unpleasant subjective sensation of inner restlessness and the need to move, often manifesting as pacing or fidgeting. This is distinct from the sustained muscle contractions seen in dystonia. - While propranolol can be used to treat akathisia, it would not resolve an **oculogyric spasm**.

Q: The following malformation in a baby due to drug intake by mother is classified as \qquad ADR?

Type D. ***Type D*** - **Type D** ADRs are **delayed effects** that include **teratogenicity** and **carcinogenicity**, occurring after prolonged exposure or during critical developmental periods. - The image shows **phocomelia** (severe limb malformation), a classic example of drug-induced teratogenicity (e.g., **thalidomide**), which is classified as a Type D ADR. *Type A* - **Type A** ADRs are **augmented** reactions that are predictable, dose-dependent pharmacological effects of drugs. - Examples include **bleeding** with anticoagulants or **hypotension** with antihypertensives, not congenital malformations. *Type E* - **Type E** ADRs are **end-of-use** effects or **withdrawal symptoms** that occur when a drug is discontinued. - These reactions (like **opioid withdrawal**) are unrelated to developmental malformations from in-utero drug exposure. *Type F* - **Type F** is not a recognized category in standard ADR classification systems, which typically include only Types A through E. - The established classification covers predictable, unpredictable, chronic, delayed, and end-of-use effects without requiring a Type F category.

Q: A 65-year-old patient of dilated cardiomyopathy was prescribed 1 mg warfarin tablet for sustained atrial fibrillation. The chemist however gave him 2 mg tablets by mistake which resulted in him developing hemorrhagic complications (bleeding). CT scan is performed. This is which kind of ADR? (Recent NEET Pattern 2016-17) Warfarin Sodium Tablets, USP Crystalline 2 mg Protect from light

Type A. ***Type A*** - This is an **exaggerated pharmacological effect** of warfarin due to a higher than intended dose, leading to excessive anticoagulation and subsequent **hemorrhagic stroke** (bleeding in the brain). - Type A ADRs are **predictable** based on the known pharmacology of the drug and are dose-dependent. *Type B* - Type B ADRs are **unpredictable**, idiosyncratic reactions that are not directly related to the pharmacological action of the drug (e.g., allergic reactions). - They are typically **dose-independent** and often occur in a small subset of the population. *Type C* - Type C ADRs are associated with **long-term exposure** to a drug, leading to chronic effects or tolerance. - Examples include drug dependence or adrenal suppression from prolonged corticosteroid use. *Type D* - Type D ADRs are also related to **delayed effects** of drug exposure, such as carcinogenesis or teratogenesis. - These effects may not manifest until months or years after the drug was taken.

Question 1

A 25-year-old woman presents to the emergency department 6 hours after ingesting a large quantity of paracetamol tablets. What is the most likely progression of paracetamol poisoning in this case?

Accepted Answer

Increase in liver enzymes starting around 24 hours

Answer

Recovery within 72 hours

Answer

Paracetamol achieves peak concentration within 4 hours

Answer

Liver failure within 24 hours

Question 2

A 50-year-old factory worker was brought to the emergency room with complaints of headache, vomiting, and blurring of vision after he consumed local spirit. Which of the following is used for the treatment of his condition?

Accepted Answer

Fomepizole

Answer

Flumazenil

Answer

N-acetyl cysteine

Answer

Naloxone

Question 3

Which of the following is a non-narcotic active principle of the opium poppy shown in the image below?

Accepted Answer

Noscapine

Answer

Morphine

Answer

Codeine

Answer

Thebaine

Question 4

The toxin shown below will cause:

Accepted Answer

Gangrene of fingers and toes

Answer

Opisthotonus

Answer

DIC

Answer

Lock jaw

Question 5

Which of the following drugs taken by the mother during pregnancy can cause the congenital defect shown in the image?

Accepted Answer

Retinoic acid

Answer

Folic acid

Answer

Niacin

Answer

Thiamine

Question 6

The condition shown in the image can be seen with all of the following EXCEPT:

Accepted Answer

Flupirtine

Answer

M4 AML

Answer

Cyclosporine

Answer

Nifedipine

Question 7

A 6-year-old child was having multiple vomiting episodes after eating at mid-day meal scheme in school. The Doctor at PHC gave injectable anti-emetics after which the child developed following posturing. What is the clinical diagnosis and what drug should be given to counteract this posturing?

Accepted Answer

Oculogyric spasm, promethazine

Answer

Tardive dyskinesia, benztropine

Answer

Malignant neuroleptic syndrome, dantrolene

Answer

Akathisia, propranolol

Question 8

A 35-year-old farmer consumed a pesticide due to inability to repay loans. On examination he is having increased sweating, salivation and muscle fasciculations. The family members have also brought the empty canister of insecticide. All are correct about the condition except: (Recent NEET Pattem 2016-17)

Accepted Answer

Ach excess at neuromuscular junction leads to hypersalivation

Answer

ECG shows 2nd degree heart block

Answer

Atropine will reverse peripheral muscular paralysis

Answer

RBC cholinesterase level decreases by >50% in organophosphate poisoning

Question 9

The following malformation in a baby due to drug intake by mother is classified as \qquad ADR?

Accepted Answer

Type D

Answer

Type A

Answer

Type E

Answer

Type F

Question 10

A 65-year-old patient of dilated cardiomyopathy was prescribed 1 mg warfarin tablet for sustained atrial fibrillation. The chemist however gave him 2 mg tablets by mistake which resulted in him developing hemorrhagic complications (bleeding). CT scan is performed. This is which kind of ADR? (Recent NEET Pattern 2016-17) Warfarin Sodium Tablets, USP Crystalline 2 mg Protect from light

Accepted Answer

Type A

Answer

Type B

Answer

Type C

Answer

Type D

Clinical Pharmacology and Drug Toxicity — MCQs

Clinical Pharmacology and Drug Toxicity — MCQs

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