Clinical Pharmacology and Drug Toxicity Practice Questions

Q: Alkalinization of urine is done in the management of poisoning with:

Aspirin. ***Aspirin*** - Alkalinization of urine is done in **aspirin overdose** to promote the **excretion of salicylic acid**, which is acidic. - By increasing the urine pH, more of the acidic aspirin metabolites become **ionized**, reducing their reabsorption in the renal tubules and increasing their elimination. *Morphine* - Morphine elimination is primarily through **hepatic metabolism** (glucuronidation) and subsequent renal excretion of inactive metabolites. - Urinary pH manipulation has **little impact** on its clearance. *Amphetamine* - Amphetamine is a **weak base**, and its excretion is enhanced by **acidification of urine**. - Alkalinization of urine would **increase reabsorption** and reduce its elimination, which is the opposite of what is desired in toxicity. *Atropine* - Atropine is primarily eliminated through **hepatic metabolism and renal excretion** of both unchanged drug and metabolites. - Manipulation of urinary pH has **minimal clinical utility** in enhancing its elimination.

Q: Which Benzodiazepine decreases post-operative nausea & vomiting:-

Midazolam. ***Midazolam*** - **Midazolam** is a commonly used benzodiazepine in anesthesia that has been shown to have **antiemetic properties** and can decrease the incidence of **postoperative nausea and vomiting (PONV)**. - Its mechanism may involve its sedative and anxiolytic effects, indirectly reducing the triggers for nausea. *Diazepam* - While **diazepam** is a benzodiazepine with sedative and anxiolytic effects, it is not primarily known for reducing PONV. - Its longer duration of action compared to midazolam can also contribute to unwanted **postoperative sedation**. *Lorazepam* - **Lorazepam** is another benzodiazepine used for anxiolysis and sedation but is not a primary agent for the prevention of PONV. - Like diazepam, its prolonged effects can lead to **delayed recovery** and drowsiness, which may not be desirable in the postoperative period. *All of the options* - While all listed drugs are benzodiazepines, only **midazolam** is consistently recognized and utilized for its ability to reduce PONV in the perioperative setting. - The other benzodiazepines do not demonstrate the same consistent benefit in PONV reduction and may have other side effects that limit their utility for this specific purpose.

Q: Which of these drugs can be a cause of rhabdomyolysis?

All of these. ***All of these*** - **Statins**, **salicylates**, and **antidepressants** (especially selective serotonin reuptake inhibitors or tricyclic antidepressants in overdose) have all been linked to cases of rhabdomyolysis. - The risk of rhabdomyolysis can increase significantly in the presence of **polypharmacy**, certain genetic predispositions, or concurrent medical conditions. **Statins (HMG-CoA reductase inhibitors)** - Well-known for their potential to cause **myopathy** and, in more severe cases, **rhabdomyolysis**, due to their effects on muscle cell integrity. - The risk is **dose-dependent** and can be exacerbated by interactions with other drugs that inhibit statin metabolism (e.g., fibrates, azole antifungals, macrolides). - Most commonly reported drug class associated with rhabdomyolysis. **Antidepressants** - Certain **antidepressants**, particularly in overdose or when combined with other serotonergic agents (leading to **serotonin syndrome**), can induce rhabdomyolysis. - **Tricyclic antidepressants (TCAs)** and **selective serotonin reuptake inhibitors (SSRIs)** have been implicated, either directly or indirectly through complications like seizures or hyperthermia. - Risk is higher in overdose situations or with drug-drug interactions. **Salicylates** - **Salicylates**, especially in cases of **acute or chronic toxicity** (e.g., **aspirin overdose**), can directly cause muscle damage leading to rhabdomyolysis. - Mechanisms involved may include uncoupling of oxidative phosphorylation, leading to **hyperthermia** and direct cellular toxicity within muscle tissue. - Less common than statins but well-documented in toxicity cases.

Q: 'Chemical mumps' is synonymous with

Iodine mumps. ***Iodine mumps*** - **Iodine mumps**, or **iodine-induced parotitis**, is a rare adverse effect of exposure to high doses of iodine-containing agents, often after diagnostic procedures using iodinated contrast media [1, 2]. - It presents with **acute, non-suppurative painful swelling** of the salivary glands, resembling infectious mumps. *Epidemic parotitis* - **Epidemic parotitis** is the medical term for **mumps**, an infectious disease caused by the mumps virus. - It is characterized by fever, headache, muscle aches, and most notably, the painful swelling of the **parotid glands**. *Nutritional mumps* - The term **nutritional mumps** is not a recognized medical condition or a synonym for iodine-induced parotitis. - While nutritional deficiencies can impact salivary gland function, they do not typically cause an acute 'mumps-like' presentation. *Nonspecific mumps* - **Nonspecific mumps** is not a standard medical term. - The term 'mumps' usually refers specifically to the viral infection (epidemic parotitis) or refers to the anatomical location of swelling (parotitis) without specifying an etiology.

Q: SLE like syndrome may be produced by all except:-

Psoralen. ***Psoralen*** - **Psoralen** is a photosensitizing drug used in combination with ultraviolet A (UVA) light (PUVA therapy) for skin conditions like **psoriasis** and **vitiligo** [2]. - While it causes photosensitivity, it is **not associated** with inducing a systemic lupus erythematosus (SLE)-like syndrome. *Sulfonamide* - **Sulfonamides** like sulfamethoxazole are known to cause drug-induced lupus, which can present with symptoms similar to SLE. - They can trigger autoimmune reactions, including the production of **antinuclear antibodies (ANAs)**. *Procainamide* - **Procainamide**, an antiarrhythmic drug, is one of the most common causes of **drug-induced lupus** [1]. - It frequently leads to the development of **anti-histone antibodies**, a hallmark of drug-induced lupus, often without renal or central nervous system involvement [1]. *Hydralazine* - **Hydralazine**, an antihypertensive medication, is also a well-known cause of **drug-induced lupus** [1]. - Like procainamide, it is associated with the production of **anti-histone antibodies** and can lead to a lupus-like syndrome [1].

Q: Drug which should not be given in renal disease is :

Gentamicin. ***Gentamicin***- **Gentamicin** is an **aminoglycoside antibiotic** known for its **nephrotoxic** properties, meaning it can cause kidney damage [1].- In patients with pre-existing renal disease, the drug can accumulate, leading to increased risk of **acute tubular necrosis** and worsening renal function, making it contraindicated or requiring significant dose adjustment.*Ceftriaxone*- **Ceftriaxone** is a third-generation **cephalosporin antibiotic** that is primarily eliminated via **biliary excretion**, with only a small portion excreted renally.- While dose adjustments may be needed in severe renal impairment, it is generally considered **safe in renal disease** compared to drugs like aminoglycosides.*Doxycycline*- **Doxycycline** is a **tetracycline antibiotic** that is primarily eliminated by non-renal routes, mainly through **fecal excretion**.- It is often favored in patients with **renal impairment** because it does not accumulate to toxic levels in the kidneys.*Nitroprusside*- **Nitroprusside** is a powerful **vasodilator** used in hypertensive emergencies, metabolized to **cyanide**, which then becomes **thiocyanate**.- Thiocyanate is primarily **renally excreted**, and in renal failure, **thiocyanate accumulation** can lead to toxicity, but the absolute contraindication is not as universal as with gentamicin, as careful monitoring can allow its use.

Q: Which drug does not lead to osteoporosis?

Thyroxine. ***Thyroxine*** - While **thyrotoxicosis** (excessive thyroid hormone levels) can accelerate bone turnover and lead to bone loss, appropriate physiological doses of **thyroxine replacement therapy** for hypothyroidism generally *do not* cause osteoporosis. - Maintaining **euthyroid status** with thyroxine replacement is crucial for overall health and does not significantly increase the risk of osteoporosis when monitored correctly. *Alcohol* - **Chronic alcohol abuse** is a significant risk factor for **osteoporosis** due to its toxic effects on osteoblasts, inhibition of calcium absorption, and nutritional deficiencies. - It also leads to increased cortisol levels and often liver disease, further contributing to **bone loss**. *Warfarin* - Long-term use of **warfarin**, an anticoagulant, has been associated with decreased bone mineral density and an increased risk of **osteoporosis**. - This is primarily due to its antagonistic effect on **vitamin K**, which is essential for the gamma-carboxylation of osteocalcin and other bone matrix proteins. *Heparin* - Both unfractionated and to a lesser extent, **low-molecular-weight heparin**, can induce **osteoporosis** with prolonged use, typically after several months. - Heparin's mechanism of action in bone involves stimulating bone resorption, inhibiting osteoblast activity, and potentially increasing the activity of collagenase.

Q: In a patient on cisplatin therapy, which of the following diuretics would be preferred?

Mannitol. ***Mannitol*** - Cisplatin is a highly **nephrotoxic** drug, and mannitol is often co-administered to induce a potent osmotic diuresis, which helps to flush out the drug and its metabolites through the kidney tubules. - This **osmotic diuretic** effect increases urine flow and minimizes the contact time of cisplatin with renal tubular cells, thereby reducing the risk and severity of **acute tubular necrosis (ATN)**. *Acetazolamide* - Acetazolamide is a **carbonic anhydrase inhibitor** primarily used for glaucoma, altitude sickness, and metabolic alkalosis. - It is not typically used to mitigate cisplatin-induced nephrotoxicity, and its mechanism does not directly address the primary toxic effects of cisplatin on renal tubules. *Thiazide* - Thiazide diuretics (e.g., hydrochlorothiazide) work by inhibiting the **sodium-chloride cotransporter** in the distal convoluted tubule. - While they promote diuresis, their effect is generally less potent than loop diuretics or osmotic diuretics, and they do not provide the same protective osmotic effect against cisplatin nephrotoxicity. *Furosemide* - Furosemide is a **loop diuretic** that acts on the thick ascending limb of the loop of Henle, producing significant diuresis. - While it can increase urine output, it does not offer the same **renal protective benefits** as mannitol against cisplatin toxicity and can potentially exacerbate electrolyte imbalances, especially **hypokalemia**, which is a concern with cisplatin.

Q: Increased osmolar gap is not seen in poisoning of:

Paracetamol. ***Paracetamol*** - **Paracetamol (acetaminophen)** poisoning does NOT cause an **increased osmolar gap** because it is not an osmotically active alcohol or small molecule that accumulates significantly in the blood. - Paracetamol toxicity primarily causes **hepatotoxicity** through the formation of the toxic metabolite **NAPQI** (N-acetyl-p-benzoquinone imine), which depletes glutathione stores. - It may cause a **high anion gap metabolic acidosis** in severe cases due to lactic acidosis from hepatic failure, but this does not increase the osmolar gap. *Methanol* - **Methanol** poisoning leads to an **increased osmolar gap** because methanol itself is a small, osmotically active alcohol that accumulates in the blood before it is metabolized. - Its toxic metabolites, **formic acid** and **formaldehyde**, contribute to the characteristic **high anion gap metabolic acidosis** with visual disturbances. *Acetone* - **Acetone** (from isopropanol ingestion) causes an **increased osmolar gap** due to the presence of acetone itself as an osmotically active substance. - Unlike methanol or ethylene glycol, acetone metabolism does not produce highly acidic byproducts, so it typically causes an **increased osmolar gap without a significant anion gap metabolic acidosis** ("osmolar gap without anion gap"). *Ethylene glycol* - **Ethylene glycol** poisoning causes an **increased osmolar gap** due to the parent compound accumulating in the blood. - Its toxic metabolites, particularly **glycolic acid** and **oxalic acid**, lead to a significant **high anion gap metabolic acidosis** with calcium oxalate crystal formation and acute kidney injury.

Q: Hypomagnesemia due to increased excretion by the kidney is caused by all except:

Digitalis. ***Digitalis*** - **Digitalis** (digoxin) is a cardiac glycoside that inhibits the **Na+/K+-ATPase pump**; it is not directly associated with renal magnesium wasting. Instead, its toxicity can be exacerbated by hypomagnesemia, but it does not cause it. - While it affects electrolyte balance intracellularly, it does not primarily lead to increased **urinary excretion of magnesium**. *Aminoglycoside* - **Aminoglycosides** like gentamicin can cause **renal tubular damage**, particularly in the distal tubules. - This damage impairs the kidney's ability to reabsorb magnesium, leading to increased **urinary magnesium excretion** and hypomagnesemia. *Furosemide* - **Furosemide** is a **loop diuretic** that inhibits the Na-K-2Cl cotransporter in the thick ascending limb of the loop of Henle. - This inhibition reduces the **transepithelial potential difference**, which in turn reduces the passive reabsorption of magnesium and calcium, leading to increased urinary excretion. *Cisplatin* - **Cisplatin** is a chemotherapeutic agent known to cause **renal tubular toxicity**, particularly affecting the distal convoluted tubule. - This toxicity often results in impaired magnesium reabsorption and consequently increased **urinary magnesium loss**.

Question 1

Alkalinization of urine is done in the management of poisoning with:

Accepted Answer

Aspirin

Answer

Morphine

Answer

Amphetamine

Answer

Atropine

Question 2

Which Benzodiazepine decreases post-operative nausea & vomiting:-

Accepted Answer

Midazolam

Answer

Diazepam

Answer

Lorazepam

Answer

All of the options

Question 3

Which of these drugs can be a cause of rhabdomyolysis?

Accepted Answer

All of these

Answer

Statins

Answer

Antidepressants

Answer

Salicylates

Question 4

'Chemical mumps' is synonymous with

Accepted Answer

Iodine mumps

Answer

Nutritional mumps

Answer

Epidemic parotitis

Answer

Nonspecific mumps

Question 5

SLE like syndrome may be produced by all except:-

Accepted Answer

Psoralen

Answer

Sulfonamide

Answer

Procainamide

Answer

Hydralazine

Question 6

Drug which should not be given in renal disease is :

Accepted Answer

Gentamicin

Answer

Ceftriaxone

Answer

Doxycycline

Answer

Nitroprusside

Question 7

Which drug does not lead to osteoporosis?

Accepted Answer

Thyroxine

Answer

Alcohol

Answer

Warfarin

Answer

Heparin

Question 8

In a patient on cisplatin therapy, which of the following diuretics would be preferred?

Accepted Answer

Mannitol

Answer

Acetazolamide

Answer

Thiazide

Answer

Furosemide

Question 9

Increased osmolar gap is not seen in poisoning of:

Accepted Answer

Paracetamol

Answer

Methanol

Answer

Acetone

Answer

Ethylene glycol

Question 10

Hypomagnesemia due to increased excretion by the kidney is caused by all except:

Accepted Answer

Digitalis

Answer

Aminoglycoside

Answer

Furosemide

Answer

Cisplatin

Clinical Pharmacology and Drug Toxicity — MCQs

Clinical Pharmacology and Drug Toxicity — MCQs

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