MCQ with Explanations on Clinical Case Studies by Dr Pharma

Case 03 • 25/01/2023

   An 18-year-old female patient is brought to the emergency department due to a drug overdose. Which of the following routes of administration is the most desirable for administering the antidote for the drug overdose? 

A. Intramuscular. 

B. Subcutaneous. 

C. Transdermal. 

D. Oral. E. Intravenous.

Correct answer = E. 

The intravenous route of administration is the most desirable because it rapidly achieves therapeutic plasma levels of the antidote.

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Case 02 • 20/01/2023

   A 65-year-old female patient (60 kg) with a history of ischemic stroke was prescribed clopidogrel for stroke prevention. She was hospitalized again after 6 months due to recurrent ischemic stroke. Which of the following is a likely reason she did not respond to clopidogrel therapy? She is a:

A. Poor CYP2D6 metabolizer. 

B. Fast CYP1A2 metabolizer. 

C. Poor CYP2E1 metabolizer. 

D. Fast CYP3A4 metabolizer. 

E. Poor CYP2C19 metabolizer. 

Correct answer = E. 

Clopidogrel is a prodrug, and it is activated by CYP2C19, which is a cytochrome P450 (CYP450) enzyme. Thus, patients who are poor CYP2C19 metabolizers have a higher incidence of cardiovascular events (for example, stroke or myocardial infarction) when taking clopidogrel. 

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Case 01 • 21/11/2022

A 60-year-old female with T2DM for over 20 years, treated with multiple daily insulin injections, came in for a routine follow-up. Her recent medical history is significant for menorrhagia secondary to uterine fibroids. Her typical A1c value is 9.0%, however, her most recent A1c value was 10.6 %. The patient is quite surprised as she has really focused on managing her diabetes over the past 3 months, and checks her blood glucose before and after meals. Her blood glucose meter download report reveals an average glucose level of 191 mg/ dL, which is consistent with an A1c value of 8.3%. The A1c value does not seem to accurately reflect mean glycemic control in this patient. What could explain the inaccuracy of her Alc value? Comment below on what other tests could be used.

A. Iron deficiency anaemia

B. Anaemia from acute or chronic blood loss

C. Hemolytic Anemia

D. Vitamin E ingestion.

Answer: (A) Iron deficiency anaemia

 Iron deficiency anemia Any condition that prolongs the life of the erythrocyte or is associated with decreased red cell turnover exposes the cell to glucose for a longer period of time, resulting in higher A1c levels. Iron deficiency anemia is a commonly reported condition associated with falsely elevated A1c. Studies in patients with and without diabetes have demonstrated that treatment of iron deficiency anemia lowers A1c, although the exact mechanism remains unclear. Similarly, any condition that shortens the life of the erythrocyte or is associated with increased red cell turnover shortens the exposure of the cell to glucose, resulting in lower A1c levels. Conditions such as acute and chronic blood loss, hemolytic anemia, and splenomegaly can all cause falsely lowered A1c results. Supplements and medications associated with falsely lowered A1c include vitamin E, Ribavirin, and interferon-alpha. Vitamin E, at doses of 600-1200 mg per day, can reduce protein glycation leading to falsely low HbA1c levels 

Nitin S. HbA1c and factors other than diabetes mellitus affecting it. Singap Med J. 2010;51:616-622.