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Episode 10

The Invisible Mistake

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Let’stryyourself

  1. A recent flu outbreak exacerbated John’s condition, leading to his death

  2. A medication error occurred at the pharmacy, leading to an overdose of antiseptic solution.

  3. John’s poor living conditions led to secondary infections that worsened his condition.

  4. The systemic toxicity was due to prolonged exposure to environmental toxins in the workshop.

  5. The combination of amoxicillin and ciprofloxacin led to a fatal drug interaction.

  6. Miscalculation and incorrect preparation of the antiseptic solution

  7. John’s diet changes interfered with his medication effectiveness, leading to complications.

  8. The wound infection spread, causing sepsis and leading to death.

  9. The wound care instructions were misinterpreted, leading to inadequate treatment.

  10. John developed a severe allergic reaction to ciprofloxacin.

DetailedAnswer

The critical error that led to John Watson’s death was the miscalculation and incorrect preparation of the antiseptic solution. The prescription required a 50% alcohol-free antiseptic solution, but due to a distraction during the preparation process, the pharmacy technician used a 70% antiseptic solution instead. This resulted in a much higher concentration than intended, leading to systemic toxicity.

 

What Went Wrong:

    •    The pharmacy technician, due to a minor distraction, failed to correctly calculate and dilute the 70% antiseptic solution to 50%. Instead, John received 1500 mL of the undiluted 70% antiseptic solution.
    •    This high concentration of antiseptic led to systemic toxicity, as confirmed by the autopsy report. The excessive antiseptic chemicals overwhelmed John’s system, exacerbating his existing condition and leading to his sudden death.

Conclusion

John Watson’s tragic death was a direct result of a critical error in the preparation of his antiseptic solution. The failure to properly dilute the 70% solution to the prescribed 50% concentration resulted in a fatal systemic overdose of antiseptic chemicals. This case underscores the importance of careful preparation and verification processes in pharmacies to prevent such fatal mistakes.

 

To prepare 1500 mL of a 50% alcohol-free antiseptic solution from a 70% antiseptic solution using a dilution method, let's determine the volume of the 70% solution and the volume of pure water required.

 

Calculation:

1. Determine the volume of the 70% solution needed:

   Use the formula for dilution:
   C1xV1 = C2xV2
   C1 is the initial concentration (70% or 0.70).
   V1 is the volume of the 70% solution needed.
   C2 is the final concentration (50% or 0.50).
   V2 is the final volume (1500 mL).

   Rearrange the formula to solve for V1:

V1 = (0.50x1500)/0.70 

V1= 1071.43

So, you would need approximately 1071.43 mL of the 70% antiseptic solution.

 

2. Determine the volume of pure water needed:

Since the total volume required is 1500 mL, the volume of pure water Vw needed can be calculated as:
   Vw = V2 - V1
   Vw = 1500 - 1071.43
   Vw = 428.57mL
   

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Pharmacotherapy and Patient Care:

  1. A patient with chronic heart failure is prescribed digoxin. What is a common sign of digoxin toxicity?

    • A) Hyperglycemia

    • B) Bradycardia

    • C) Jaundice

    • D) Dry mouth

  2. A 45-year-old patient with anxiety is prescribed sertraline. What is an important counseling point for this medication?

    • A) Avoid grapefruit juice

    • B) Take the medication with food

    • C) It may take several weeks to see improvement

    • D) Monitor for signs of hypoglycemia

  3. A patient with hypertension is being treated with amlodipine. What is a common side effect of this medication?

    • A) Cough

    • B) Edema

    • C) Hyperkalemia

    • D) Dizziness

  4. A 60-year-old patient is started on levothyroxine for hypothyroidism. What is the most important counseling point regarding this medication?

    • A) Take it with a full glass of water

    • B) Avoid taking it with calcium or iron supplements

    • C) It should be taken in the evening

    • D) It is important to take it with food

  5. A patient with chronic obstructive pulmonary disease (COPD) is prescribed tiotropium. What is the primary mechanism of action of this drug?

    • A) Beta-agonist

    • B) Anticholinergic

    • C) Corticosteroid

    • D) Leukotriene receptor antagonist

Pharmacokinetics:

  1. If a drug has a half-life of 6 hours, how many hours will it take for the drug to be reduced to 25% of its original concentration?

    • A) 6 hours

    • B) 12 hours

    • C) 18 hours

    • D) 24 hours

  2. A drug is administered orally and has a bioavailability of 80%. If the patient receives a 50 mg dose, what amount of the drug is absorbed into the bloodstream?

    • A) 10 mg

    • B) 20 mg

    • C) 40 mg

    • D) 50 mg

  3. What is the volume of distribution (Vd) if a drug has a dose of 100 mg and a plasma concentration of 2 mg/L?

    • A) 50 L

    • B) 100 L

    • C) 200 L

    • D) 500 L

Biostatistics:

  1. In a clinical trial, the absolute risk reduction (ARR) is 5% and the incidence in the control group is 15%. What is the incidence in the treatment group?

    • A) 10%

    • B) 15%

    • C) 20%

    • D) 25%

  2. A study has a p-value of 0.03. What does this indicate about the study's findings?

    • A) The results are not statistically significant

    • B) There is a 3% chance the results are due to random chance

    • C) The results are statistically significant

    • D) The study has a high risk of bias

Medication Safety:

  1. A patient on warfarin presents with a bleeding episode. What is the appropriate immediate management?

    • A) Administer activated charcoal

    • B) Increase the dose of warfarin

    • C) Administer vitamin K

    • D) Discontinue warfarin and start aspirin

  2. A patient develops a rash and fever after starting allopurinol. What is the most likely diagnosis?

    • A) Drug-induced lupus

    • B) Stevens-Johnson syndrome

    • C) Urticaria

    • D) Erythema multiforme

Compounding:

  1. A prescription requires 0.2% sodium chloride solution. If you have a 0.9% sodium chloride solution, how many milliliters of the 0.9% solution are needed to prepare 500 mL of the 0.2% solution?

    • A) 111 mL

    • B) 200 mL

    • C) 222 mL

    • D) 300 mL

  2. What is the proper procedure for sterilizing equipment used in compounding sterile products?

    • A) Wipe with alcohol

    • B) Use a dry heat sterilizer

    • C) Autoclave

    • D) Clean with a disinfectant spray

Immunizations:

  1. Which of the following vaccines is recommended for all adults annually to prevent a respiratory infection?

    • A) Hepatitis B

    • B) Tdap

    • C) Influenza

    • D) Varicella

  2. For which patient population is the zoster vaccine (Shingrix) recommended?

    • A) Adults aged 50 and older

    • B) Children aged 6 months and older

    • C) Adults aged 18-49

    • D) Pregnant women

Infectious Diseases:

  1. What is the first-line treatment for a patient with uncomplicated urinary tract infection (UTI)?

    • A) Ciprofloxacin

    • B) Trimethoprim-sulfamethoxazole

    • C) Vancomycin

    • D) Azithromycin

  2. A patient diagnosed with tuberculosis (TB) is started on a standard regimen. What is a key medication included in this regimen?

    • A) Rifampin

    • B) Azithromycin

    • C) Ceftriaxone

    • D) Doxycycline

Oncology:

  1. A patient with breast cancer is receiving tamoxifen. What is the primary mechanism of action of this medication?

    • A) Aromatase inhibition

    • B) Estrogen receptor antagonist

    • C) DNA alkylation

    • D) Topoisomerase inhibition

  2. What is a common side effect of taxane-based chemotherapy agents like paclitaxel?

    • A) Neuropathy

    • B) Hepatotoxicity

    • C) Hyperglycemia

    • D) Hyperkalemia

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ANSWERS:

Pharmacotherapy and Patient Care:

  1. B) Bradycardia
    Explanation: Digoxin toxicity commonly presents with bradycardia (slow heart rate) as a result of its effect on the heart's electrical conduction system.

  2. C) It may take several weeks to see improvement
    Explanation: SSRIs like sertraline often require several weeks to show their full therapeutic effects due to their mechanism of action on neurotransmitter levels in the brain.

  3. B) Edema
    Explanation: Amlodipine, a calcium channel blocker, often causes peripheral edema as a common side effect due to its vasodilatory properties.

  4. B) Avoid taking it with calcium or iron supplements
    Explanation: Levothyroxine absorption can be reduced by calcium and iron supplements, so it's important to take levothyroxine separately from these products.

  5. B) Anticholinergic
    Explanation: Tiotropium is an anticholinergic medication used as a long-acting bronchodilator in COPD to help relax the muscles around the airways.

Pharmacokinetics:

  1. C) 18 hours
    Explanation: The drug will be reduced to 25% of its original concentration after 2 half-lives (6 hours x 2 = 12 hours) plus an additional 6 hours for the remaining quarter (18 hours in total).

  2. C) 40 mg
    Explanation: With 80% bioavailability, 40 mg of the 50 mg oral dose is absorbed into systemic circulation (50 mg x 0.80 = 40 mg).

  3. B) 50 L
    Explanation: Volume of distribution (Vd) is calculated using the formula Vd = Dose / Plasma concentration. For a dose of 100 mg and plasma concentration of 2 mg/L, Vd = 100 mg / 2 mg/L = 50 L.

Biostatistics:

  1. A) 10%
    Explanation: Absolute Risk Reduction (ARR) of 5% from an initial incidence of 15% gives a treatment group incidence of 10% (15% - 5% = 10%).

  2. C) The results are statistically significant
    Explanation: A p-value of 0.03 indicates that there is a 3% chance that the results are due to random chance, meaning the results are statistically significant.

Medication Safety:

  1. C) Administer vitamin K
    Explanation: Vitamin K is used to reverse the effects of warfarin and is the appropriate immediate management for bleeding complications due to warfarin.

  2. B) Stevens-Johnson syndrome
    Explanation: Stevens-Johnson syndrome is a severe reaction to allopurinol that presents with rash and fever, requiring immediate medical attention.

Compounding:

  1. C) 222 mL
    Explanation: To prepare a 0.2% sodium chloride solution from a 0.9% solution, use the dilution formula: (C1 x V1 = C2 x V2). For 500 mL of 0.2%, V1 = (0.2% / 0.9%) x 500 mL = 222 mL.

  2. C) Autoclave
    Explanation: Autoclaving is the most effective method for sterilizing equipment used in compounding sterile products, ensuring that all microorganisms are killed.

Immunizations:

  1. C) Influenza
    Explanation: The influenza vaccine is recommended annually for all adults to protect against seasonal flu.

  2. A) Adults aged 50 and older
    Explanation: The zoster vaccine (Shingrix) is recommended for adults aged 50 and older to prevent shingles.

Infectious Diseases:

  1. B) Trimethoprim-sulfamethoxazole
    Explanation: Trimethoprim-sulfamethoxazole is a first-line treatment for uncomplicated urinary tract infections due to its effectiveness against common UTI pathogens.

  2. A) Rifampin
    Explanation: Rifampin is a key medication in the standard regimen for treating tuberculosis (TB), used to target the TB bacteria.

Oncology:

  1. B) Estrogen receptor antagonist
    Explanation: Tamoxifen acts as an estrogen receptor antagonist, blocking estrogen from binding to its receptor on cancer cells, which helps treat estrogen-positive breast cancer.

  2. A) Neuropathy
    Explanation: Paclitaxel, a taxane-based chemotherapy agent, is commonly associated with peripheral neuropathy as a side effect.

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