CHAPTER 25 – DRUGS AFFECTING THE KIDNEY AND BLADDER Flashcards
Brian, a 67 year old male, has a history of hypertension that has been treated for a number of years with angiotensin converting enzyme (ACE) inhibitor enalapril. He has made several visits to the health centre over the past 6 months and on each occasion his blood pressure has been higher than expected. The prescriber decides to change his medication to a combination tablet of enapril (20mg) and hydrochlorothiazide (6mg) once daily, and advises Brian that the combination drug contains a diuretic
Brian, a 67 year old male, has a history of hypertension that has been treated for a number of years with angiotensin converting enzyme (ACE) inhibitor enalapril. He has made several visits to the health centre over the past 6 months and on each occasion his blood pressure has been higher than expected. The prescriber decides to change his medication to a combination tablet of enapril (20mg) and hydrochlorothiazide (6mg) once daily, and advises Brian that the combination drug contains a diuretic
- As an observing health professional you are asked to explain to the prescriber how hydrochlorothiazide promotes diuresis.
Hydrochlorothiazide works by inhibiting reabsorption of sodium and chloride by blocking the binding to this site. Being that it is a thiazide diuretic it promotes renal excretion of water, sodium, chloride, potassium and magnesium
Brian asks you to explain to him any adverse effects he should be aware of.
Brian asks you to explain to him any adverse effects he should be aware of.
- Which common adverse effects of hydrocholothiazide are most likely to be problematic for Brian?
Brian may experience hypotension as he is also taking enapril which is also a decreases hypertension. Also Brian’s electrolyte balance may also be effected as well as his potassium levels.
Brain remains well for several months but on his latest visit he complains of pain and inflammation of his big toe joint. He indicates that he is unable to sleep because of the pain.
Brain remains well for several months but on his latest visit he complains of pain and inflammation of his big toe joint. He indicates that he is unable to sleep because of the pain.
- What is the most likely explanation for his big toe?
Brian is most likely experiencing Gout which due to an increase in plasma uric acid.
- Explain how hydrochlorothiazide may have contributed to Brian’s problem
Patients receiving thiazide diuretics may have an increase in plasma uric acid. This increase is persistent and may result from inhibition of tubular secretion of uric acid resulting from competition for the organic acid secretory pump in the proximal tubule or increased uric acid reabsorption
Brian tells the prescriber that because his toe was so painful he has taken for the last 5 days some of his wife’s prescribed non-steroidal anti-inflammatory drugs (NSAIDs). The prescriber takes Brian’s BP, which is elevated, advises Brian that he should not have taken the NSAIDs and immediately orders some renal function tests.
Brian tells the prescriber that because his toe was so painful he has taken for the last 5 days some of his wife’s prescribed non-steroidal anti-inflammatory drugs (NSAIDs). The prescriber takes Brian’s BP, which is elevated, advises Brian that he should not have taken the NSAIDs and immediately orders some renal function tests.
- Explain why the prescriber has ordered the renal function tests.
Renal toxicity with diuretics occurs frequently, especially amongst the elderly, via diminished renal excretion, altered plasma protein binding and interactions with other drugs such as non-steroidal anti-inflammatory drugs (NSAIDs). Remember that renal function may diminish over time or with concurrent illness..
- With regard to the NSAID Brian has taken, what is the explanation for his elevated BP?
Decreased naturiuresis and reduced antihypertensive and antihypertensive effect. In view of increased potential for nephrotoxicity, avoid concurrent use or adjust dose of diuretic.
