Clinical Pharmacology and Drug Toxicity Practice Questions

Q: Which of the following substances is not classified as a carcinogen for bladder cancer?

Isopropyl alcohol. ***Isopropyl alcohol*** - Research does not link **isopropyl alcohol** to an increased risk of bladder cancer, making it a non-carcinogenic substance in this context. - It is commonly used as a solvent and antiseptic, but has not shown **urogenic carcinogenicity** in studies. *Phenacetin* - **Phenacetin** is an analgesic that has been associated with an increased risk of bladder cancer, particularly due to its metabolite, which can be nephrotoxic. - Its use has significantly declined due to its carcinogenic effects on the urinary system. *Benzidine* - **Benzidine** is a well-known bladder carcinogen, primarily linked to the dye industry, where exposure has led to increased rates of bladder cancer [1]. - This substance has been implicated in **urothelial carcinoma** due to its mutagenic properties. *Acrolein* - **Acrolein** is a toxic compound that can cause bladder irritation and has been studied for its potential carcinogenic effects related to bladder cancer. - It is released during the combustion of materials and is known to contribute to **chemical injury** in the bladder. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. (Basic Pathology) introduces the student to key general principles of pathology, both as a medical science and as a clinical activity with a vital role in patient care. Part 2 (Disease Mechanisms) provides fundamental knowledge about the cellular and molecular processes involved in diseases, providing the rationale for their treatment. Part 3 (Systematic Pathology) deals in detail with specific diseases, with emphasis on the clinically important aspects., pp. 217-218.

Q: Which of the following is classified as a Type E adverse reaction?

Rebound effect due to drug withdrawal. ***Rebound effect due to drug withdrawal*** - Type E adverse reactions are related to **end-of-treatment effects**, specifically withdrawal phenomena. - The **rebound effect** after drug cessation, such as worsened angina after stopping beta-blockers, is a classic example of a Type E reaction. *Toxicity* - This is a general term for adverse effects from excessive drug doses and is **not a specific type** in the ABCDEF classification. - Dose-dependent toxic effects typically align with **Type A** (augmented) reactions, which are predictable and related to the drug's pharmacology. *Augmented effect* - An **augmented effect** is classified as a Type A adverse drug reaction, meaning it is **dose-dependent**, predictable from the drug's known pharmacology, and common. - Examples include bleeding with anticoagulants or hypotension with antihypertensives. *Teratogenesis* - **Teratogenesis** refers to drug-induced fetal malformations and is categorized as a **Type D** (delayed) adverse drug reaction. - These effects are often severe, occur after prolonged exposure, and are rare.

Q: Microvesicular fatty liver is caused by ?

Valproate. ***Valproate*** - **Valproate** is a known cause of **microvesicular steatosis**, particularly in children, due to its interference with mitochondrial fatty acid oxidation. - This can lead to severe liver injury, including **acute liver failure**, as it impairs the liver's ability to metabolize fats. *Chronic diabetes mellitus (DM)* - Chronic DM is commonly associated with **macrovesicular steatosis** (NAFLD), not microvesicular, due to insulin resistance and increased hepatic lipid synthesis. - Unlike microvesicular steatosis, macrovesicular type usually does not immediately impair mitochondrial function. *Prolonged starvation* - Prolonged starvation can lead to **fatty liver**, usually **macrovesicular steatosis**, as the body mobilizes fatty acids from adipose tissue. - While it stresses the liver, it rarely causes the specific **microvesicular** pattern of fat accumulation. *Chronic inflammatory bowel disease (IBD)* - IBD can cause various liver complications, but **microvesicular fatty liver** is not a characteristic feature. - Liver issues in IBD are more often related to **sclerosing cholangitis** or secondary to nutritional deficiencies and medications.

Q: Which of the following substances is known to cause predominantly sensory neuropathy?

Cisplatin. ***Cisplatin*** - **Cisplatin** is a platinum-based chemotherapy drug well-known for causing **dose-dependent peripheral neuropathy**, primarily affecting sensory neurons. - Patients often present with **numbness**, **tingling**, and **loss of proprioception** in a glove-and-stocking distribution. - This is the **most characteristic** drug for **predominantly sensory neuropathy** among chemotherapeutic agents. *Pyridoxine excess* - While **pyridoxine (vitamin B6) excess** can cause sensory neuropathy, it is less commonly observed as a primary cause compared to cisplatin in the context of drug-induced neuropathies. - High doses of pyridoxine can lead to **dorsal root ganglionopathy**, affecting sensory nerve fibers. *Suramin* - **Suramin** is an anthelmintic agent primarily used for treating sleeping sickness, and it is known to cause a variety of side effects, including **renal toxicity** and **neurological symptoms**. - While neurological side effects can occur, they are not typically characterized as a **predominantly sensory neuropathy** in the same way as cisplatin. *Vincristine* - **Vincristine** is a vinca alkaloid chemotherapy agent that causes peripheral neuropathy. - However, vincristine typically causes **mixed motor and sensory neuropathy** with prominent motor involvement (foot drop, wrist drop). - This differs from cisplatin's **predominantly sensory** presentation.

Q: All of the following occurs because of prostaglandin use except?

Excess water retention. ***Excess water retention*** - **Prostaglandins** generally promote **diuresis** and natriuresis, meaning they help the body excrete water and sodium, rather than retain them [2]. - While some prostaglandins can affect renal blood flow, direct causation of **excess water retention** as a primary side effect is not typical. *Flushes* - **Prostaglandins**, particularly **PGE1** and **PGE2**, are potent **vasodilators** and can cause cutaneous vasodilation, leading to **flushing** and a sensation of warmth [3]. - This effect is often mediated by the relaxation of vascular smooth muscle. *Increased motility of bowel* - Many **prostaglandins**, especially **PGE** and **PGF** series, stimulate **smooth muscle contraction**, including in the gastrointestinal tract [1]. - This increased contraction can lead to **enhanced bowel motility**, sometimes causing diarrhea or abdominal cramping [1]. *Nausea* - **Prostaglandins** can have various systemic effects, and activation of pathways in the central nervous system or direct irritation of the GI tract can lead to symptoms like **nausea** and vomiting [1]. - This is a common side effect, especially with systemic administration.

Q: What is the drug of choice for malaria in pregnancy?

Chloroquine. ***Chloroquine*** - **Chloroquine** is the drug of choice for **uncomplicated malaria in pregnancy** caused by **chloroquine-sensitive** strains of *P. vivax*, *P. ovale*, *P. malariae*, and *P. falciparum* [1]. - It has an **established safety profile** in pregnancy across all trimesters and is considered safe by WHO and CDC. - While resistance has emerged in many areas for *P. falciparum*, chloroquine remains effective for *P. vivax* malaria in most regions including India. - For **severe malaria** or **chloroquine-resistant falciparum malaria**, alternative regimens like quinine or artesunate are used [1]. *Quinine* - **Quinine** (usually with clindamycin) is the preferred treatment for **severe malaria** or **chloroquine-resistant *P. falciparum*** malaria in pregnancy, especially in the **first trimester**. - It is safe and effective but can cause side effects like **cinchonism** (tinnitus, headache, nausea) and **hypoglycemia**. - While safe throughout pregnancy, it is not the first-line choice for uncomplicated chloroquine-sensitive malaria. *Primaquine* - **Primaquine** is **contraindicated in pregnancy** because it can cause **hemolytic anemia** in individuals with **G6PD deficiency**, and G6PD status of the fetus cannot be determined [3]. - It is used for **radical cure** of *P. vivax* and *P. ovale* to eliminate liver hypnozoites, but must be deferred until after delivery [3]. *Artesunate* - **Artesunate** and other **artemisinin-based combination therapies (ACTs)** are highly effective antimalarials [2]. - Current WHO guidelines support ACT use in all trimesters for severe malaria when benefits outweigh risks. - For **uncomplicated falciparum malaria**, ACTs are preferred in the **second and third trimesters** in areas with chloroquine resistance [2]. - However, chloroquine remains the classical "drug of choice" for uncomplicated, chloroquine-sensitive malaria in pregnancy [1].

Q: Long-term steroid ingestion leads to all of the following except:

Hypoglycemia. ***Hypoglycemia*** - Chronic steroid use primarily leads to **hyperglycemia** due to increased **gluconeogenesis** and **insulin resistance**, not hypoglycemia. - Steroids raise blood glucose levels, potentially inducing or worsening **diabetes mellitus**. *Avascular necrosis of head of femur* - Long-term steroid use is a well-established risk factor for **avascular necrosis**, particularly affecting the **femoral head**. - This occurs due to impaired blood supply to the bone, leading to its death. *Cataract* - **Posterior subcapsular cataracts** are a known ocular complication of prolonged systemic corticosteroid therapy. - The mechanism involves direct effects of steroids on lens metabolism and protein aggregation. *Growth retardation* - In children, chronic corticosteroid therapy can suppress growth, leading to **growth retardation**. - This is due to interference with **growth hormone secretion** and direct effects on bone formation.

Q: What is the recommended dosage for chloroquine chemoprophylaxis in malaria prevention?

500 mg once weekly. ***500 mg once weekly*** - The recommended dosage for chloroquine chemoprophylaxis in malaria prevention is **500 mg salt** (or equivalent to 300 mg base) administered **once weekly**. - This regimen ensures adequate blood concentrations to prevent malarial infection in endemic areas. *500 mg/week* - While the 500 mg dose is correct, simply stating "500 mg/week" without specifying "once weekly" could be misinterpreted. - Chloroquine is generally taken as a **single weekly dose**, not divided doses. *400 mg once weekly* - A dosage of **400 mg** is **sub-therapeutic** for weekly chloroquine chemoprophylaxis. - This dose would likely not provide sufficient protection against malaria. *500 mg BD/week* - Taking chloroquine **twice weekly (BD/week)** at 500 mg is excessive for chemoprophylaxis. - This regimen can lead to increased side effects and toxicity without providing additional prophylactic benefit.

Q: Which of the following best describes a Type B adverse drug reaction?

Unpredictable bizarre reaction. ***Unpredictable bizarre reaction*** - Type B reactions are **unpredictable**, **bizarre**, and not directly related to the drug's known pharmacological actions. - They often involve **immunological reactions** or genetic predispositions, such as allergies or idiosyncratic responses. *Augmented effect of drug* - This describes a **Type A** adverse drug reaction, which is predictable and results from an **exaggerated pharmacological effect** of the drug. - It is typically dose-dependent and can be managed by adjusting the dosage. *Effect seen on chronic use of drug* - This description can apply to several types of adverse reactions, but it commonly relates to **Type C (chronic) reactions**, where effects occur only after prolonged exposure. - These reactions might be due to **cumulative toxicity** or adaptive changes in the body. *Delayed effect of drug* - This aligns with **Type D (delayed) adverse drug reactions**, which manifest long after the drug exposure has ended or after a period of latency. - Examples include **carcinogenesis** or teratogenesis, occurring months or years later.

Q: Which of the following antiepileptic drugs is most classically associated with causing hirsutism?

Phenytoin. ***Phenytoin*** - **Phenytoin** is the **most classically associated** antiepileptic drug with **hirsutism**, which is abnormal/excessive growth of hair [1]. - The mechanism involves changes in **androgen metabolism** and stimulation of hair follicle growth. - Other cosmetic side effects include **gingival hyperplasia** and **coarsening of facial features** [1].*Valproate* - Valproate can paradoxically cause both **hair loss (alopecia)** and **hirsutism**, particularly in women and children. - However, phenytoin has a **stronger and more classical association** with hirsutism. - Valproate is also known for **weight gain**, **hepatotoxicity**, **pancreatitis**, and **teratogenicity**.*Carbamazepine* - Carbamazepine's common side effects include **drowsiness**, **dizziness**, **diplopia**, and **hyponatremia**. - It is not classically linked to **hirsutism** as a prominent adverse effect. - Can cause **agranulocytosis** and **Stevens-Johnson syndrome** in rare cases.*Phenobarbitone* - Phenobarbitone is an older antiepileptic drug associated with **sedation**, **cognitive impairment**, and **dependence**. - It does not commonly cause **hirsutism**. - Also causes **enzyme induction** leading to multiple drug interactions.

Question 1

Which of the following substances is not classified as a carcinogen for bladder cancer?

Accepted Answer

Isopropyl alcohol

Answer

Acrolein

Answer

Phenacetin

Answer

Benzidine

Question 2

Which of the following is classified as a Type E adverse reaction?

Accepted Answer

Rebound effect due to drug withdrawal

Answer

Toxicity

Answer

Augmented effect

Answer

Teratogenesis

Question 3

Microvesicular fatty liver is caused by ?

Accepted Answer

Valproate

Answer

Chronic diabetes mellitus (DM)

Answer

Prolonged starvation

Answer

Chronic inflammatory bowel disease (IBD)

Question 4

Which of the following substances is known to cause predominantly sensory neuropathy?

Accepted Answer

Cisplatin

Answer

Pyridoxine excess

Answer

Suramin

Answer

Vincristine

Question 5

All of the following occurs because of prostaglandin use except?

Accepted Answer

Excess water retention

Answer

Increased motility of bowel

Answer

Nausea

Answer

Flushes

Question 6

What is the drug of choice for malaria in pregnancy?

Accepted Answer

Chloroquine

Answer

Primaquine

Answer

Artesunate

Answer

Quinine

Question 7

Long-term steroid ingestion leads to all of the following except:

Accepted Answer

Hypoglycemia

Answer

Avascular necrosis of head of femur

Answer

Growth retardation

Answer

Cataract

Question 8

What is the recommended dosage for chloroquine chemoprophylaxis in malaria prevention?

Accepted Answer

500 mg once weekly

Answer

500 mg/week

Answer

400 mg once weekly

Answer

500 mg BD/week

Question 9

Which of the following best describes a Type B adverse drug reaction?

Accepted Answer

Unpredictable bizarre reaction

Answer

Augmented effect of drug

Answer

Effect seen on chronic use of drug

Answer

Delayed effect of drug

Question 10

Which of the following antiepileptic drugs is most classically associated with causing hirsutism?

Accepted Answer

Phenytoin

Answer

Valproate

Answer

Carbamazepine

Answer

Phenobarbitone

Clinical Pharmacology and Drug Toxicity — MCQs

Clinical Pharmacology and Drug Toxicity — MCQs

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