Your Daily Meds - 9 December, 2022
Good morning and welcome to your Friday dose of Your Daily Meds.
Bonus Review: So what is a reticulocyte?
Answer: It’s an erythrocyte in the final stage of maturation. Erythrocytes enter the blood and extrude their basophilic cellular debris (RNA, mitochondria, other organelles in their cytoplasm) over a couple of days. Reticulocytes should be about 1% of all red cells.
When recovering from blood loss, with increased erythropoeisis in the bone marrow, naturally more reticulocytes enter the blood.
Pharmacology Corner:
On the wards, you are asked by your registrar to prescribe Apixaban for the patient you have just reviewed. You recall something about monitoring renal function before prescribing those ‘-ban’ drugs - Apixaban and Rivaroxaban. Which of the following creatinine clearance values is the lowest value at which Apixaban should be given?
Calculated creatinine clearance less than 15 mL/min
Calculated creatinine clearance less than 25 mL/min
Calculated creatinine clearance less than 60 mL/min
Calculated creatinine clearance less than 45 mL/min
Calculated creatinine clearance less than 75 mL/min
Have a think and meet me further down for the answer and discussion.
Case:
You have been asked by the Nurses to prescribe something for the 28-year-old (non-pregnant) female in Bed 6 who is complaining of headache associated with nausea and vomiting, photophobia and sound sensitivity. Which of the following is least likely to help in reducing the nausea?
Metoclopramide 10mg intramuscularly
Domperidone 10 mg orally
Ondansetron 4 mg intravenously
Prochlorperazine 5 mg orally
Diclofenac potassium 50 mg orally
Pause here, pick an answer, and meet me at the bottom.
Back to the Med Chart:
Answer: Calculated creatinine clearance less than 25 mL/min
Apixaban is a direct factor Xa inhibitor - taken orally and significantly renally excreted.
It should not be used in patients with severe kidney impairment, with calculated creatinine clearance less than 25 mL/min, or severe liver impairment.
Creatinine clearance is calculated from the patient’s sex, age, weight and serum creatinine using the Cockroft-Gault equation.
Meanwhile on The Ward:
This sounds like Migraine.
Migraines need nonopioid analgesics (first) +/- triptans. If there is nausea, an oral antiemetic should be trialled. Recommended antiemetics include metoclopramide, domperidone, ondansetron and prochlorperazine.
Metoclopramide - blocks dopamine receptors and, if in higher doses, serotonin receptors, of the chemoreceptor trigger zone (CTZ) of the central nervous system.
Domperidone - blocks dopamine receptors in the periphery and does not easily cross the blood brain barrier. It increases oesophageal peristalsis, increases lower oesophageal pressure and increases gastric motility and peristalsis.
Ondansetron - a selective 5-HT3-receptor antagonist, blocking serotonin peripherally on vagal nerve terminals and centrally in the CTZ.
Prochlorperazine - an antipsychotic medication which acts to block postsynaptic mesolimbic D1 and D2 receptors in the brain, including in the CTZ.
So - Diclofenac potassium, an NSAID that reversibly inhibits cyclooxygenase-1 and -2 enzymes, is least likely to help in reducing the nausea of migraines.
FOAMED Friday:
Heparin Induced Thrombocytopaenia
A Virtual Journey into the Heart
News: I made a little Ward Call Course for you all. It maps out an Evening Ward Call shift and covers a bunch of common tasks that you may need to do, like:
Deteriorating Patients
Heparin Infusions
Fluid Orders
Electrolyte Replacement
Difficult patients - Discharge Against Medical Advice, Ryan’s Rule
End of Life etc
You can find the course page here:
It’s free and always will be. Let me know what you think.
Remember, you are free to rip these questions and answers and use them for your own flashcards, study and question banks.
As always, please contact me with any questions, concerns, tips or suggestions. Have a great day!
Luke.