Antibiotic anticancer drugs – Dactinomycin MCQs With Answer

Antibiotic anticancer drugs – Dactinomycin MCQs With Answer

Antibiotic anticancer drugs such as dactinomycin (Actinomycin D) are essential in B. Pharm curricula because they combine microbial origin with potent antineoplastic effects. Dactinomycin intercalates DNA and inhibits RNA synthesis, producing cytotoxicity in rapidly dividing cells. It is widely used in pediatric solid tumors (Wilms tumor, rhabdomyosarcoma, Ewing sarcoma) and gestational trophoblastic neoplasia. Key learning points include mechanism of action, pharmacokinetics, dose-limiting myelosuppression, hepatotoxicity, resistance mechanisms, drug interactions, handling, and clinical regimens. Mastering these topics improves safe chemotherapy preparation, monitoring, and patient counseling. This set of MCQs focuses on mechanisms, clinical uses, adverse effects, dosing, storage, and monitoring, with emphasis on B. Pharm exam relevance. Now let’s test your knowledge with 30 MCQs on this topic.

Q1. What is the primary mechanism of action of dactinomycin (actinomycin D)?

• Inhibition of topoisomerase II
• Intercalation into DNA and inhibition of RNA polymerase/transcription
• Alkylation of guanine bases
• Inhibition of microtubule polymerization

Correct Answer: Intercalation into DNA and inhibition of RNA polymerase/transcription

Q2. Which of the following best describes the main clinical indications for dactinomycin?

• Chronic myeloid leukemia and prostate cancer
• Wilms tumor, rhabdomyosarcoma, Ewing sarcoma and gestational trophoblastic neoplasia
• Metastatic melanoma and renal cell carcinoma
• Non-small cell lung cancer and head and neck cancer

Correct Answer: Wilms tumor, rhabdomyosarcoma, Ewing sarcoma and gestational trophoblastic neoplasia

Q3. Dactinomycin is produced by which microorganism?

• Streptomyces parvulus
• Streptomyces griseus
• Bacillus subtilis
• Penicillium notatum

Correct Answer: Streptomyces parvulus

Q4. Dactinomycin is also commonly known as:

• Dactinomycin (Actinomycin D)
• Adriamycin
• Bleomycin
• Mitomycin C

Correct Answer: Dactinomycin (Actinomycin D)

Q5. What is the primary dose-limiting toxicity of dactinomycin?

• Neurotoxicity
• Cardiotoxicity
• Myelosuppression
• Nephrotoxicity

Correct Answer: Myelosuppression

Q6. Dactinomycin most directly inhibits which cellular process?

• DNA replication
• RNA transcription
• Mitosis (spindle formation)
• Protein translation

Correct Answer: RNA transcription

Q7. How should dactinomycin be stored to preserve stability?

• At room temperature exposed to light
• Refrigerated and protected from light
• Frozen at −20 °C
• Stored at 37 °C

Correct Answer: Refrigerated and protected from light

Q8. The primary route of elimination for dactinomycin is:

• Renal excretion of unchanged drug
• Biliary excretion and fecal elimination
• Pulmonary exhalation
• Secretion in sweat

Correct Answer: Biliary excretion and fecal elimination

Q9. What is the FDA pregnancy category for dactinomycin?

• Category A
• Category B
• Category C
• Category D

Correct Answer: Category D

Q10. Which chemotherapy regimen commonly includes dactinomycin for pediatric tumors?

• R-CHOP
• VAC (vincristine, actinomycin D, cyclophosphamide)
• FOLFOX
• BEP

Correct Answer: VAC (vincristine, actinomycin D, cyclophosphamide)

Q11. A common mechanism of resistance to dactinomycin involves:

• Increased activation by intracellular enzymes
• Increased drug efflux via P-glycoprotein (multidrug resistance)
• Enhanced drug uptake into cells
• Selective inhibition of drug-metabolizing enzymes

Correct Answer: Increased drug efflux via P-glycoprotein (multidrug resistance)

Q12. Which mucosal adverse effect is commonly observed with dactinomycin therapy?

• Ototoxicity
• Mucositis / stomatitis
• Photosensitivity dermatitis
• Peripheral neuropathy

Correct Answer: Mucositis / stomatitis

Q13. Dactinomycin’s inhibition of transcription occurs primarily by:

• Blocking DNA replication forks
• Blocking RNA polymerase progression along DNA (transcriptional blockade)
• Inhibiting ribosomal subunits
• Disrupting spindle microtubules

Correct Answer: Blocking RNA polymerase progression along DNA (transcriptional blockade)

Q14. Prior to each dose of dactinomycin, which laboratory test is most important to monitor?

• Fasting blood glucose
• Complete blood count (CBC)
• Thyroid function tests
• Serum amylase

Correct Answer: Complete blood count (CBC)

Q15. On extravasation risk classification, dactinomycin is considered a:

• Non-vesicant
• Irritant only
• Vesicant (can cause severe local tissue necrosis)
• Purely emetogenic agent with no local effects

Correct Answer: Vesicant (can cause severe local tissue necrosis)

Q16. Dose adjustment of dactinomycin is most often required in which organ impairment?

• Renal impairment
• Hepatic impairment
• Pulmonary impairment
• Ocular impairment

Correct Answer: Hepatic impairment

Q17. Which adverse effect is least commonly associated with dactinomycin?

• Myelosuppression
• Mucositis
• Cardiotoxicity
• Alopecia

Correct Answer: Cardiotoxicity

Q18. Which structural feature of dactinomycin intercalates into DNA?

• Anthracycline ring
• Phenoxazone chromophore
• Platinum coordination center
• Taxane diterpene nucleus

Correct Answer: Phenoxazone chromophore

Q19. What is the usual route of administration for dactinomycin in clinical practice?

• Oral
• Intravenous (IV)
• Intramuscular (IM)
• Topical

Correct Answer: Intravenous (IV)

Q20. In case of dactinomycin overdose, the most appropriate immediate management is:

• Activated charcoal administration
• Administration of dexrazoxane as an antidote
• Supportive care and symptomatic management
• Naloxone reversal

Correct Answer: Supportive care and symptomatic management

Q21. Which hematologic abnormality is a sensitive early indicator of dactinomycin toxicity?

• Neutropenia
• Hyperglycemia
• Hyponatremia
• Hyperkalemia

Correct Answer: Neutropenia

Q22. Concurrent use of which category of drugs increases the risk of severe toxicity with dactinomycin?

• Aminoglycoside antibiotics
• Other bone marrow suppressants (e.g., cyclophosphamide)
• Topical antihistamines
• Beta blockers

Correct Answer: Other bone marrow suppressants (e.g., cyclophosphamide)

Q23. Which pediatric tumor is classically treated with dactinomycin as part of first-line therapy?

• Acute lymphoblastic leukemia
• Wilms tumor
• Small cell lung cancer
• Hodgkin lymphoma

Correct Answer: Wilms tumor

Q24. Pharmacokinetically, dactinomycin is best described as:

• Primarily renally excreted unchanged with minimal tissue binding
• Highly protein bound with extensive tissue binding and enterohepatic cycling
• Rapidly metabolized to inactive metabolites excreted in urine
• Excreted unchanged via pulmonary routes

Correct Answer: Highly protein bound with extensive tissue binding and enterohepatic cycling

Q25. A local sign suggestive of dactinomycin extravasation injury is:

• Generalized maculopapular rash
• Blistering and local tissue necrosis at the infusion site
• Immediate anaphylaxis with bronchospasm
• Diffuse peripheral neuropathy

Correct Answer: Blistering and local tissue necrosis at the infusion site

Q26. Which antiemetic class is commonly used as prophylaxis with dactinomycin-containing regimens?

• Anticholinergics (e.g., scopolamine)
• 5-HT3 receptor antagonists (e.g., ondansetron)
• Opioid antagonists (e.g., naloxone)
• Loop diuretics (e.g., furosemide)

Correct Answer: 5-HT3 receptor antagonists (e.g., ondansetron)

Q27. Which pharmacokinetic phenomenon is notable with dactinomycin and affects dosing considerations?

• Rapid renal clearance without enterohepatic recycling
• Enterohepatic recirculation and prolonged tissue retention
• Exclusive pulmonary elimination
• Complete first-pass metabolism after oral dosing

Correct Answer: Enterohepatic recirculation and prolonged tissue retention

Q28. Regarding reproductive effects, dactinomycin is associated with:

• No reproductive toxicity
• Increased fertility in both sexes
• Potential gonadal toxicity and impaired fertility in both sexes
• Only transient effects with no long-term impact

Correct Answer: Potential gonadal toxicity and impaired fertility in both sexes

Q29. Dose reduction of dactinomycin is most clearly indicated in which situation?

• Severe renal impairment with creatinine clearance <30 mL/min
• Severe hepatic impairment with elevated bilirubin or transaminases
• Mild asthma
• Controlled hypothyroidism

Correct Answer: Severe hepatic impairment with elevated bilirubin or transaminases

Q30. Dactinomycin is classified pharmacologically as a:

• Platinum-based alkylating agent
• Antimetabolite
• Antitumor antibiotic
• Taxane mitotic inhibitor

Correct Answer: Antitumor antibiotic

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