Clinical Pharmacology and Drug Toxicity Practice Questions

Q: Which of the following is the most commonly reported pharmacological agent causing peliosis hepatis?

Anabolic steroids. ***Anabolic steroids*** - **Anabolic androgenic steroids** are consistently linked to peliosis hepatis, a condition characterized by **blood-filled cysts** within the liver. - The liver damage resulting from anabolic steroid use is often **dose-dependent** and can also lead to other complications like **hepatic adenomas** and **cholestasis**. *Methotrexate* - While methotrexate is a known cause of **hepatotoxicity**, it typically manifests as **fibrosis** and **cirrhosis**, not peliosis hepatis. - Its mechanism of liver injury involves direct cellular damage, distinct from the **vascular changes** seen in peliosis hepatis. *Pyrazinamide* - Pyrazinamide is an **anti-tuberculosis drug** well-known for its potential to cause **hepatocellular injury**, leading to **elevated liver enzymes** and **hepatitis**. - Its primary liver pathology does not involve the formation of **blood-filled cysts** characteristic of peliosis hepatis. *Interferon Alpha* - Interferon alpha can cause various adverse effects, including **flu-like symptoms**, **myelosuppression**, and **neuropsychiatric effects**. - While it can impact liver function, severe **hepatic vascular disorders** like peliosis hepatis are **not commonly associated** with its use.

Q: Methemoglobinemia is associated with:

Prilocaine. ***Prilocaine*** - **Prilocaine** is a local anesthetic known to cause **methemoglobinemia** at higher doses due to its metabolite, **o-toluidine**. - This metabolite oxidizes iron in hemoglobin from the ferrous (Fe2+) to the ferric (Fe3+) state, rendering it unable to bind oxygen. *Aminoester local anesthetic* - While some aminoester local anesthetics can cause allergic reactions, they are not typically associated with **methemoglobinemia**. - **Methemoglobinemia** is more commonly linked with aminoamide local anesthetics containing specific chemical structures. *Bupivacaine* - **Bupivacaine** is an aminoamide local anesthetic primarily known for its potential to cause **cardiotoxicity** at high systemic concentrations. - It does not commonly induce **methemoglobinemia**. *Mepivacaine* - **Mepivacaine** is another aminoamide local anesthetic, chemically similar to lidocaine. - While it can cause CNS toxicity and cardiovascular effects at high doses, it is not a significant cause of **methemoglobinemia**.

Q: Constipation is a possible side effect of drugs taken by the oral route. Which of the following medications is least likely to cause constipation?

docusate. ***docusate*** - **Docusate** is a **stool softener** and is actually used to prevent and treat constipation, making it the least likely to cause it. - It works by increasing the amount of water and fat the stool absorbs, making it easier to pass. *promethazine* - **Promethazine** is an antihistamine with **anticholinergic properties** that can slow down gut motility. - Reduced gastrointestinal motility is a common side effect of drugs with anticholinergic effects, leading to **constipation**. *loperamide* - **Loperamide** is an **opioid receptor agonist** that works by slowing down gut contractions. - It is specifically used as an **antidiarrheal medication**, and constipation is a well-known side effect of its action. *diphenhydramine* - **Diphenhydramine** is an antihistamine with significant **anticholinergic effects**. - Its anticholinergic action reduces intestinal motility and secretions, frequently causing **constipation**.

Q: Which one of the following nonsteroidal anti-inflammatory drugs has adverse effects on the liver?

Diclofenac Sodium. ***Diclofenac Sodium*** - **Diclofenac** is the NSAID most commonly associated with **hepatotoxicity** among commonly prescribed NSAIDs - Can cause **elevated liver enzymes** (transaminases) and in rare cases **severe hepatotoxicity** leading to acute liver failure - Has **black box warnings** in many countries regarding hepatic adverse effects - **Regular monitoring of liver function tests** is recommended for patients on long-term diclofenac therapy - Hepatotoxicity risk is dose-dependent and more common with prolonged use *Aspirin* - Aspirin (acetylsalicylic acid) is an NSAID with primary adverse effects related to **gastrointestinal irritation**, **bleeding**, and **antiplatelet effects** - In children, associated with **Reye's syndrome** (hepatic encephalopathy) - Very high doses or chronic use can cause mild, reversible liver enzyme elevations, but **significant hepatotoxicity is uncommon** in adults - Not prominently associated with liver toxicity compared to diclofenac *Ibuprofen* - Ibuprofen is a well-tolerated NSAID with most common adverse effects being **gastrointestinal discomfort**, **peptic ulcers**, and **renal impairment** - Although NSAIDs as a class can rarely cause idiosyncratic liver injury, ibuprofen has a **very low incidence of hepatotoxicity** - Considered one of the safer NSAIDs regarding hepatic effects *Naproxen* - Naproxen is a commonly used NSAID with primary adverse effects similar to other NSAIDs: **gastrointestinal irritation** and **renal effects** - Hepatotoxicity is **rare** with naproxen compared to diclofenac - Generally well-tolerated with respect to liver function - Idiosyncratic liver injury can occur but is uncommon

Q: Sterile pyuria may occur due to:

Phenytoin. ***Phenytoin*** - **Phenytoin** is a well-known cause of **drug-induced acute interstitial nephritis (AIN)**, which is a classic cause of **sterile pyuria**. - **Acute interstitial nephritis** presents with inflammatory infiltration of the renal interstitium, leading to pyuria (white blood cells in urine) **without bacterial infection**. - Other features of drug-induced AIN include fever, rash, eosinophilia, and acute kidney injury. - Phenytoin, along with other drugs like penicillins, NSAIDs, and rifampicin, can trigger this hypersensitivity-mediated renal injury. *Paracetamol* - **Paracetamol (acetaminophen)** overdose causes **acute tubular necrosis (ATN)**, not interstitial nephritis. - ATN primarily presents with acute kidney injury, oliguria, and elevated creatinine, but **sterile pyuria is not a characteristic feature** of ATN. - The renal damage is direct tubular cell injury rather than inflammatory interstitial infiltration. *Lignocaine* - **Lignocaine (lidocaine)** is a local anesthetic and antiarrhythmic agent with side effects primarily affecting the **central nervous system and cardiovascular system**. - It is **not associated with renal toxicity** or sterile pyuria. *Cocaine* - **Cocaine** can cause kidney damage through **rhabdomyolysis**, **vasoconstriction**, and **hypertensive crisis**, leading to **acute kidney injury**. - While cocaine-related AKI can occur, it does not typically cause **drug-induced interstitial nephritis** or classic sterile pyuria. - Renal injury from cocaine is usually related to ischemic or myoglobinuric mechanisms rather than inflammatory infiltration.

Q: Belimumab is used in

Systemic lupus erythematosus. ***Systemic lupus erythematosus*** - **Belimumab** is a monoclonal antibody that targets and inhibits **B-cell activating factor (BAFF)**, reducing the survival of autoreactive B cells. - This medication is FDA-approved for the treatment of **active systemic lupus erythematosus (SLE)** in patients who are receiving standard therapy. *Osteoporosis* - **Osteoporosis** is primarily treated with bisphosphonates, denosumab, teriparatide, or romosozumab, which focus on bone density and remodeling. - Belimumab has **no direct mechanism of action** for increasing bone mass or preventing bone resorption. *Malignant melanoma* - **Malignant melanoma** is typically treated with surgical excision, targeted therapies (e.g., BRAF/MEK inhibitors), or immunotherapies (e.g., PD-1 or CTLA-4 inhibitors). - Belimumab's mechanism of action, targeting B-cell activating factor, is **not relevant to the treatment of melanoma**. *Merkel cell carcinoma* - **Merkel cell carcinoma** is a rare and aggressive skin cancer primarily treated with surgery, radiation, and immunotherapy, particularly PD-1 inhibitors like avelumab. - Belimumab's role in modulating B-cell activity **does not apply to the pathogenesis or treatment of Merkel cell carcinoma**.

Q: What is the cause of cough and angioedema in a patient receiving ACE inhibitors?

Bradykinin accumulation. ***Bradykinin accumulation*** - **ACE inhibitors** block the enzyme **angiotensin-converting enzyme (ACE)**, which is responsible for degrading **bradykinin**. - The resulting **accumulation of bradykinin** is a potent vasodilator and increases capillary permeability, leading to **cough** (5-20% of patients) and **angioedema** (0.1-0.7%). - This is the most **precise answer** as it specifies the mechanism: impaired degradation leading to accumulation. *Bradykinin (alone)* - While **bradykinin** is the mediator involved, this option is **less precise** than "bradykinin accumulation." - **Bradykinin** is naturally present in the body; the problem with ACE inhibitors is specifically the **accumulation** due to impaired degradation. - The correct answer requires understanding that it's the **excess levels**, not just the presence, that causes symptoms. *Increased renin levels* - **ACE inhibitors** block the conversion of **angiotensin I to angiotensin II**, leading to reduced negative feedback. - This causes **compensatory increase in renin secretion** from the juxtaglomerular apparatus. - However, increased renin is **not responsible** for cough or angioedema—these are bradykinin-mediated effects. *Increased angiotensin-II levels* - **ACE inhibitors** actually **decrease angiotensin-II levels**, which is their primary **antihypertensive mechanism**. - This option is **incorrect** as ACE inhibitors reduce (not increase) angiotensin-II. - The reduction in angiotensin-II does not cause cough or angioedema.

Q: All of the following drugs are used in acute congestive glaucoma EXCEPT:

Atropine. ***Atropine*** - **Atropine** is a **muscarinic antagonist** that causes **mydriasis** (pupil dilation). - In acute congestive glaucoma, pupillary dilation can further narrow the **angle of the anterior chamber**, exacerbating the condition and increasing intraocular pressure. *Pilocarpine* - **Pilocarpine** is a **cholinergic agonist** that causes **miosis** (pupil constriction), pulling the iris away from the trabecular meshwork. - This action helps to **open the anterior chamber angle** and facilitate aqueous humor outflow, thus reducing intraocular pressure. *Acetazolamide* - **Acetazolamide** is a **carbonic anhydrase inhibitor** that reduces the production of **aqueous humor** by the ciliary body. - This leads to a decrease in intraocular pressure, making it a crucial medication in the management of acute glaucoma. *Mannitol* - **Mannitol** is an **osmotic diuretic** that creates an osmotic gradient, drawing fluid from the eye into the systemic circulation. - This effect rapidly reduces **intraocular volume** and pressure, making it useful in acute glaucoma crises.

Q: Adverse reactions following whole cell pertussis immunization include:

All of the options. ***All of the options*** - **Whole-cell pertussis vaccines** are associated with a range of common, generally self-limiting adverse reactions. - These include systemic effects like **fever** and irritability, often manifested by excessive crying, as well as local reactions at the injection site. *Fever* - **Fever** is a very common systemic adverse reaction following whole-cell pertussis immunization, indicating the body's immune response. - This reaction typically resolves within 24-48 hours. *Excessive cry* - **Excessive crying** (often described as inconsolable crying) for several hours is a known systemic adverse effect of whole-cell pertussis vaccines. - This symptom usually reflects irritability and discomfort experienced by the infant. *Local swelling* - **Local swelling** at the injection site, along with redness and tenderness, is a frequent local adverse reaction to whole-cell pertussis immunization. - These local reactions are generally mild and self-limiting, resolving within a few days.

Question 1

Which of the following is the most commonly reported pharmacological agent causing peliosis hepatis?

Accepted Answer

Anabolic steroids

Answer

Methotrexate

Answer

Pyrazinamide

Answer

Interferon Alpha

Question 2

Methemoglobinemia is associated with:

Accepted Answer

Prilocaine

Answer

Aminoester local anesthetic

Answer

Bupivacaine

Answer

Mepivacaine

Question 3

Constipation is a possible side effect of drugs taken by the oral route. Which of the following medications is least likely to cause constipation?

Accepted Answer

docusate

Answer

promethazine

Answer

loperamide

Answer

diphenhydramine

Question 4

Which one of the following nonsteroidal anti-inflammatory drugs has adverse effects on the liver?

Accepted Answer

Diclofenac Sodium

Answer

Aspirin

Answer

Ibuprofen

Answer

Naproxen

Question 5

Sterile pyuria may occur due to:

Accepted Answer

Phenytoin

Answer

Cocaine

Answer

Lignocaine

Answer

Paracetamol

Question 6

A woman consumes several tablets of amitriptyline (a case of amitriptyline poisoning). Which of the following is NOT an appropriate management step?

Accepted Answer

Atropine as antidote

Answer

Gastric lavage

Answer

Sodium bicarbonate infusion

Answer

Activated charcoal administration

Question 7

Belimumab is used in

Accepted Answer

Systemic lupus erythematosus

Answer

Osteoporosis

Answer

Malignant melanoma

Answer

Merkel cell carcinoma

Question 8

What is the cause of cough and angioedema in a patient receiving ACE inhibitors?

Accepted Answer

Bradykinin accumulation

Answer

Bradykinin

Answer

Increased renin levels

Answer

Increased angiotensin-II levels

Question 9

All of the following drugs are used in acute congestive glaucoma EXCEPT:

Accepted Answer

Atropine

Answer

Mannitol

Answer

Pilocarpine

Answer

Acetazolamide

Question 10

Adverse reactions following whole cell pertussis immunization include:

Accepted Answer

All of the options

Answer

Fever

Answer

Local swelling

Answer

Excessive cry

Clinical Pharmacology and Drug Toxicity — MCQs

Clinical Pharmacology and Drug Toxicity — MCQs

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