Pediatric and Geriatric Pharmacology — MCQs

Pediatric and Geriatric Pharmacology Indian Medical PG Practice Questions and MCQs

Question 51: Which drug is linked to hypertrophic pyloric stenosis in infants?

A. Erythromycin (Correct Answer)
B. Ampicillin
C. Rifampicin
D. Tetracycline

Explanation: ***Erythromycin*** - Studies have shown an association between infantile exposure to **erythromycin** and an increased risk of developing **hypertrophic pyloric stenosis**. - This risk is particularly noted when erythromycin is administered during the **first two weeks of life**, possibly due to its potent motilin receptor agonism. *Tetracycline* - **Tetracycline** is known for causing **teeth discoloration** and **bone growth retardation** in infants and children. - It is generally contraindicated in pediatric populations due to these significant side effects, but it is not linked to pyloric stenosis. *Ampicillin* - **Ampicillin** is a penicillin antibiotic commonly used in infants for bacterial infections. - While it can cause side effects like **rashes** and **diarrhea**, there is no established link to hypertrophic pyloric stenosis. *Rifampicin* - **Rifampicin** is an antibiotic primarily used for treating tuberculosis. - Its main side effects include **hepatotoxicity** and **red-orange discoloration of body fluids**, but it has no known association with hypertrophic pyloric stenosis.

Question 52: Which antithyroid drug is preferred during the first trimester of pregnancy due to relatively lower placental transfer?

A. Carbimazole
B. Propylthiouracil (Correct Answer)
C. Both
D. None of the options

Explanation: ***Propylthiouracil*** - **Propylthiouracil (PTU)** is the preferred antithyroid drug during the **first trimester** of pregnancy because it crosses the placenta less readily than methimazole/carbimazole. - While it still crosses the placenta, its lower placental transfer and association with fewer fetal anomalies in early pregnancy make it a safer initial choice, especially to minimize the risk of **fetal embryopathy** associated with methimazole. *Carbimazole* - **Carbimazole** (which is metabolized to methimazole) can cross the placenta more easily than PTU and has been associated with **fetal anomalies**, particularly in the first trimester. - Its use is generally avoided during the first trimester due to concerns about congenital malformations such as **aplasia cutis** and **esophageal atresia**. *Both* - While both drugs can cross the placenta to some extent, their safety profiles and recommended use during pregnancy differ significantly. - Carbimazole (methimazole) has a higher risk of teratogenicity in the first trimester compared to PTU. *None of the options* - This option is incorrect because propylthiouracil is indeed known to cross the placenta and is commonly used in pregnancy, especially during the first trimester. - The choice of antithyroid drug is a critical consideration in managing hyperthyroidism in pregnancy.

Question 53: What is the drug of choice for managing generalized tonic-clonic seizures (GTCS) during pregnancy?

A. Lamotrigine (Correct Answer)
B. CBZ
C. Levetiracetam
D. Valproate

Explanation: ***Lamotrigine*** - **Lamotrigine** is considered **one of the preferred drugs** for managing epilepsy during pregnancy due to its relatively **low teratogenic risk** compared to older antiepileptic drugs. - Its established safety profile in pregnancy makes it a preferred option to balance seizure control and **fetal well-being**. - **Important Note:** For **GTCS specifically**, lamotrigine and levetiracetam are both considered appropriate first-line choices, with selection depending on individual patient factors and seizure control history. - Lamotrigine levels **decrease during pregnancy** and require monitoring and dose adjustments. *CBZ* - **Carbamazepine (CBZ)** is associated with an increased risk of **neural tube defects** and other congenital malformations when used during pregnancy, making it less favorable. - While effective for GTCS, its teratogenicity often leads to avoidance or careful consideration of alternatives in pregnant women. *Levetiracetam* - **Levetiracetam** is increasingly recognized as an **excellent choice for GTCS in pregnancy** with a favorable safety profile and growing evidence base. - Many recent guidelines and clinical practices favor levetiracetam as **first-line for GTCS** due to its low risk of major congenital malformations and good efficacy. - It is a **medically appropriate alternative** to lamotrigine, and in some contexts may be preferred, particularly for primary generalized epilepsy. *Valproate* - **Valproate** has the highest risk of **teratogenicity** among common antiepileptic drugs, including a significant risk of **neural tube defects**, developmental delay, autism spectrum disorder, and other anomalies. - Due to these significant risks, valproate is generally **contraindicated** in women of childbearing potential, especially during pregnancy, unless no other effective and safer alternative exists.

Question 54: What is the initial loading dose of chloroquine base for treating uncomplicated malaria in children?

A. 5 mg/kg
B. 10 mg/kg (maximum 600 mg) (Correct Answer)
C. 15 mg/kg
D. 25 mg/kg

Explanation: ***10 mg/kg (maximum 600 mg)*** - The standard **initial loading dose** of chloroquine base for uncomplicated malaria in children is **10 mg/kg body weight**, with a maximum cap of **600 mg** to prevent toxicity. - This is followed by **5 mg/kg** at 6 hours, 24 hours, and 48 hours (total course of 25 mg/kg over 3 days). - This represents **WHO-recommended** weight-based dosing for pediatric malaria treatment. *5 mg/kg* - **5 mg/kg** is the dose for the **subsequent doses** (at 6, 24, and 48 hours after the initial dose), not the initial loading dose. - The initial dose must be higher (10 mg/kg) to rapidly achieve therapeutic blood levels. *15 mg/kg* - **15 mg/kg** exceeds the recommended initial dose and increases the risk of **chloroquine toxicity**. - Chloroquine has a narrow therapeutic index, and overdosing can cause serious **cardiovascular** (arrhythmias, hypotension) and **neurological** effects (seizures, visual disturbances). *25 mg/kg* - **25 mg/kg** represents the **total cumulative dose** over the entire 3-day treatment course, not the initial single dose. - Giving this amount as a single dose would result in severe toxicity and is contraindicated.

Question 55: What is the recommended dose of oseltamivir for a child aged 9 months?

A. 2 mg/kg twice daily for 5 days
B. 2.5 mg/kg twice daily for 5 days
C. 3 mg/kg twice daily for 5 days (Correct Answer)
D. 3.5 mg/kg twice daily for 5 days

Explanation: ***3 mg/kg twice daily for 5 days*** - For children aged **less than 1 year**, and weighing less than 15 kg, the recommended oseltamivir dose is **3 mg/kg** administered **twice daily** for 5 days. - This dosage regimen is effective in treating influenza and is based on studies of its **pharmacokinetics** and **efficacy** in this age group. *2 mg/kg twice daily for 5 days* - This dosage is **lower than recommended** for children under 1 year of age and may not achieve adequate therapeutic drug levels. - Subtherapeutic dosing could lead to **reduced antiviral efficacy** and potentially poorer clinical outcomes. *2.5 mg/kg twice daily for 5 days* - Similar to the 2 mg/kg dose, this is **below the standard recommendation** for infants and young children in this age bracket. - Inadequate dosing increases the risk of **treatment failure** and the development of **antiviral resistance**. *3.5 mg/kg twice daily for 5 days* - This dosage might be considered **higher than necessary** for a 9-month-old child and could potentially increase the risk of **adverse effects**. - While exact toxicities are rare within a reasonable range, adherence to recommended guidelines optimizes the **benefit-risk profile**.

Question 56: What is the drug of choice for hypertension in pregnancy?

A. Verapamil
B. Methyldopa (Correct Answer)
C. Furosemide
D. Enalapril

Explanation: ***Methyldopa*** - **Methyldopa** is considered a first-line agent because of its established safety profile for both the mother and the fetus throughout pregnancy. - It acts centrally as an **alpha-2 adrenergic agonist**, reducing sympathetic outflow and thereby lowering blood pressure. *Enalapril* - **Angiotensin-converting enzyme (ACE) inhibitors** like Enalapril are contraindicated in pregnancy due to their association with **fetal renal abnormalities**, **oligohydramnios**, and **growth restriction**, especially in the second and third trimesters. - Their use can lead to **fetal hypotension** and potentially **fetal death**. *Verapamil* - **Calcium channel blockers** like Verapamil are generally considered second-line agents for hypertension in pregnancy. - While generally safer than ACE inhibitors, **Labetalol** and **Nifedipine** are often preferred among calcium channel blockers, and **Methyldopa** has a longer track record of safety. *Furosemide* - **Diuretics** like Furosemide are generally not recommended for chronic hypertension in pregnancy as they can **reduce plasma volume** and potentially impair placental perfusion. - They are primarily used in cases of **pulmonary edema** or severe fluid overload, rather than routine management of hypertension.

Question 57: Which of the following drugs is given during pregnancy, resulting in fetal abnormalities such as cleft lip and central nervous system defects?

A. Warfarin
B. Phenytoin
C. Valproic acid
D. Retinoic acid (Vitamin A derivative) (Correct Answer)

Explanation: ***Retinoic acid (Vitamin A derivative)*** - **Retinoic acid** (including isotretinoin) is a **potent teratogen** with a characteristic pattern of malformations including **craniofacial defects (cleft lip/palate)**, **cardiac abnormalities** (transposition of great arteries, VSD), and **severe CNS defects** (hydrocephalus, microcephaly, neural tube defects) - The mechanism involves **disruption of gene expression** during embryogenesis, particularly affecting **neural crest cell migration** critical for facial and cardiac development - The combination of **cleft lip + CNS defects** is characteristic of retinoic acid embryopathy, making it the most fitting answer *Phenytoin* - **Phenytoin** causes **fetal hydantoin syndrome** with craniofacial anomalies (cleft lip/palate in ~5-10% of cases), **hypoplastic nails and distal phalanges**, wide-set eyes, and mild developmental delays - While cleft lip can occur, the overall pattern emphasizes **digital/nail hypoplasia** and milder CNS effects compared to retinoic acid *Valproic acid* - **Valproic acid** is primarily associated with **neural tube defects** (spina bifida in 1-2% of exposures), the hallmark of valproate embryopathy - Can cause minor facial anomalies and cardiac defects, but the **characteristic feature is spina bifida**, not cleft lip *Warfarin* - **Warfarin** causes **fetal warfarin syndrome** with distinctive features: **nasal hypoplasia**, **stippled epiphyses** (chondrodysplasia punctata), and potential CNS defects from hemorrhage - Does **not** typically cause cleft lip; the skeletal abnormalities are the defining feature

Question 58: Which of the following drugs can cause cartilage damage in children?

A. Cotrimoxazole and other sulfonamides
B. Penicillin and other beta-lactams
C. Metronidazole and other nitroimidazoles
D. Ciprofloxacin and other fluoroquinolones (Correct Answer)

Explanation: ***Ciprofloxacin and other fluoroquinolones*** - Fluoroquinolones, including ciprofloxacin, are known to cause **arthropathy** (joint disease) and **cartilage damage** in growing children and adolescents [1]. - This adverse effect has limited their use in pediatric populations, typically reserved for severe infections where other effective and safer alternatives are unavailable [1]. *Cotrimoxazole and other sulfonamides* - Sulfonamides are primarily associated with adverse effects like **hypersensitivity reactions** (e.g., Stevens-Johnson syndrome), **bone marrow suppression**, and **crystalluria**. - They are not typically linked to cartilage damage in children. *Penicillin and other beta-lactams* - Penicillins and other beta-lactam antibiotics are generally considered **safe in children** and are a common choice for pediatric infections. - Their primary adverse effects are hypersensitivity reactions, such as **rashes** or **anaphylaxis**, and gastrointestinal disturbances, not cartilage damage. *Metronidazole and other nitroimidazoles* - Metronidazole's main adverse effects include **gastrointestinal upset**, **metallic taste**, and **neurological symptoms** (e.g., peripheral neuropathy, seizures with high doses). - There is no known association between metronidazole and cartilage damage in children.

Question 59: Which drug is considered safest for treating latent tuberculosis in pregnancy?

A. INH (Correct Answer)
B. Rifampicin
C. Ethambutol
D. Streptomycin

Explanation: ***INH (Isoniazid)*** - **Isoniazid (INH)** is considered the **safest and preferred agent** for treating **latent tuberculosis infection (LTBI)** in pregnant women. - It can be given as a **6-9 month daily regimen** with **pyridoxine (vitamin B6)** supplementation to prevent maternal and fetal **peripheral neuropathy**. - Well-studied with extensive safety data in pregnancy (FDA Category A/C depending on source, but generally considered safe). *Rifampicin* - While generally safe in pregnancy for **active TB**, its use for **LTBI** is often deferred or avoided, particularly in the first trimester, due to theoretical concerns. - **Rifampicin** can interact with other medications through hepatic enzyme induction, which might be a consideration for pregnant women on multiple therapies. - Not the first-line choice for LTBI monotherapy in pregnancy. *Ethambutol* - **Ethambutol** is primarily used in **multi-drug regimens** for **active tuberculosis** and is less commonly used alone for **LTBI**. - Although generally considered safe in pregnancy, **INH** remains the preferred monotherapy for LTBI treatment due to more extensive safety data. *Streptomycin* - **Streptomycin** is **contraindicated during pregnancy** due to significant risk of **ototoxicity** (damage to cranial nerve VIII) in the fetus, leading to **permanent congenital deafness**. - It is an **aminoglycoside antibiotic** and should be avoided in pregnant women unless absolutely necessary for life-threatening conditions with no other alternatives.

Question 60: Which antimalarial drug is considered the safest during pregnancy?

A. Chloroquine (Correct Answer)
B. Pyrimethamine
C. None of the options
D. Proguanil

Explanation: ***Chloroquine*** - **Chloroquine** is considered the **safest antimalarial drug during pregnancy** and is the drug of choice for malaria prophylaxis and treatment in pregnant women. - It has been used extensively for decades with an **excellent safety profile** across all trimesters, including the first trimester. - Classified as **FDA Pregnancy Category C**, chloroquine has extensive clinical data supporting its safety, with no significant teratogenic effects reported. - **WHO and CDC** both recommend chloroquine as the preferred antimalarial for pregnant women in chloroquine-sensitive malaria areas. - It is effective against **Plasmodium vivax** and chloroquine-sensitive **P. falciparum** strains. *Pyrimethamine* - **Pyrimethamine** is a **dihydrofolate reductase inhibitor** that interferes with folate metabolism, which is crucial during pregnancy for fetal neural tube development. - Should be used with **caution in the first trimester** due to risk of **folate deficiency** and potential teratogenicity. - When used (typically as sulfadoxine-pyrimethamine), it must be co-administered with **folic acid supplementation** to reduce risks. - Not considered first-line due to these concerns. *Proguanil* - **Proguanil** is relatively safe but is typically used in **combination therapy** (atovaquone-proguanil) rather than as monotherapy. - While it has a reasonable safety profile as a **dihydrofolate reductase inhibitor**, it has **less extensive safety data** during pregnancy compared to chloroquine. - Generally considered a **second-line option** when chloroquine-resistant malaria is present. - Often requires folate supplementation when used during pregnancy. *None of the options* - This is incorrect because **chloroquine** is definitively recognized as the safest antimalarial during pregnancy, with decades of safe use and endorsement by major health organizations including WHO and CDC.

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