Question

a.) Morgan, a 65-year old female, has been prescribed a thiazide diuretic for the treatment of hypertension. She has achieved good blood pressure control. She unfortunately dropped a rock on her foot which caused quite a bit of blunt force trauma. As she is in pain and her foot has swollen, she decides to start taking naproxen. After a few days, she starts feeling ill, and her blood pressure registers higher than it typically does (145/90 mmHg). Regarding her pharmacotherapy, explain i) how the thiazide diuretic assists with blood pressure control, ii) how naproxen will control pain and inflammation, and iii) why her blood pressure suddenly increased. (10½)

b.) After consulting her physician, Morgan recovers and her blood pressure starts to decrease. She takes a holiday overseas soon thereafter with her husband, and experiences some oedema in her legs due to the flight. She figures that the diuretic will help remedy this, so decides to increase the dose to reduce the swelling quicker. Increasing the dosage does not increase the effect of the drug dramatically though. Explain the i) rationale of using her diuretic for her oedema treatment, and ii) why the increased concentration did not cause a significant effect.

Answer 1

(i) Thiazide diuretic functions in such a way that they expands the blood vessels, making the blood flow easy and hence lowers the blood pressure. Secondly they also flushes out the extra salt (sodium) and fluid from the body through urine and relaxes the blood flow by reducing the amount of fluid and hence controls blood pressure.

(ii) Naproxen is nothing but a strong pai killer and belong to non-steroidal anti-inflammatory drugs category. They functions by decreasing the pain and inflammation causing hormones in the body and are widely used as pain relieving agent for conditions like headache, muscle aches and menstrual cramps.

(iii) The use of non-steroidal anti-inflammatory drug i.e. Naproxen suddenly increased her blood pressure. The afferent arterioles are type of blood vessels that plays a major role in regulating blood pressure. Non-steroidal anti-inflammatory drugs tightens them and blocks eicosanoids responsible for causing hormones effect(stated earlier)

This results in lowering of renal perfusion flow and retention of excess body fluid and hence raises the blood pressure.

(b) Diuretics works on a simple mechanism of eliminating excess fluid from the body by causing the kidney to expel more sodium and fluid from the body. In oedema, fluid retention take place in the body and this fluid causes part to become swollen. She thought of getting rid of this fluid with the use of diuretics. When diuretics are taken, intravascular fluids are taken ou tfrom the body. But due to this reduction in capillary hydraulic pressure, the oedema mobilizes again inside the intravascular space. Secondly, diuretics starts its working within 1-2 hours of administration but the effects can take longer time to reflect. These two are the reasons why the increased concentration did not caused a significant effect with Morgan.