Pharmacology - diuretics Flashcards
What is the role of diuretics?
to increase the amount of water and salt expelled from the body as urine
prevent fluid/mineral reabsorption in the kidney nephrons
What are they also known as?
Water tablets
What sports may use diuretics?
Aesthetic/weight category sports
-judo, gymnastics, boxing, ballet
Where they want to decrease bw
What are they able to do if a person is taking other drugs?
Diuretics can mask the presence of other drugs in urine samples
What are diuretics used to treat?
HT, heart failure and other CV problems
What other food/nutrients have diuretic effects?
Caffeine
alcohol
Give examples of different types of diuretics
bendroflumethiazide - used for HT
frurosemide - most potent - lose minerals (Na, K, Mg) rapidly
spironolactone - lose fluid but preserve loss of minerals
acetazolamide - used for glaucoma or mountain/altitude sickness
How do diuretics work specifically?
target transport systems which prevents reabsorption of water and electrolytes which is urinated out
there is a reduction in fluid and salt content in the body and a decrease in circulating blood volume
- aim is to reduce BP
What is the effect of long term regular exercise and diuretics use?
Negative water balance causing a drop in BP which would enhance the effects of diuretics
How does exercise effect intracellular K+ in blood vessels?
It acutely shifts intracellular K=, adrenaline/noradrenaline levels increase which drives K= back into cells
- we don’t lose a massive amount of K with diuretics
What effect does thiazide have on insulin resistance?
enhances IR which increases the risk of diabetes, exercise does the opposite - decreases IR
There is an increased risk in patients taking thiazide and BB of diabetes therefore only chose BB if really necessary
What are the varying effects of diuretics on exercisers?
Loss of volume and electrolytes
<40% VO2 max - small effects of GFR and urine flow
>60% VO2 max - big decrease in urine flow and GFR
ADH decreased with HI exercise
Fluid loss causes decreases in BP, HR and increased SV and ability to thermoregulate may be difficult so performance is sacrificed
Decreased blood skin flow
K+ is moved to ECF or lost in urine causing muscle fatigue
Inference with long term training as RAAS doesn’t function normally
Loop diuretics may lower respiratory capacity and VO2 max at higher dosages
How do diuretics affect performance?
Detrimental effect to aerobic and muscle performance if hypohydrated
- even after rehydrated, detrimental effects on performance and recovery
K+ causes muscle fatigue and nerve conduction problems when it is lost in urine and in ECF
Reduced thermoregulation because circulating blood volume is decreased and required more in essential organs
- more chance of fainting and reaching exhaustion quicker
CA inhibitors - useful in hypotoxic conditions to improve respiratory capacity but detrimental in normative conditions - cause acidosis
Effects of abusing diuretics
Hyperthermia/heat exhaustion decreased exercise duration photosensitivity if exercising outdoors muscle cramps or cardiac arrhythmia caused by electrolyte loss disqualification of competition
Is it banned in competitions?
Yes unless there is a proven HT case
Basic guidance and tips for diuretic use
Rapid dehydration limits performance
HT patients have a limited tolerance to exercise so adjust targets
Avoid use of other fluid lose methods
Patients still sweat out when exercising so replace fluid carefully to avoid electrolyte imbalances
Wear suncream if using thiazide
Usually take in morning to avoid interrupted sleep patterns and to monitor urine output
