Diuretics also called water or fluid pills, because it helps the body remove excess sodium and water, which help control blood pressure. It is more effective if the cause of hypertension is due to fluid built up in the body.
How does diuretics work? Diuretics also called as ‘fluid or water pills,’ because it causes you to pass more urine than usual. Diuretics work on your kidneys and make it to flushing sodium out of your body along with the unwanted extra fluid. This sodium and water removal will reduce blood volume and thus lowered your blood pressure.
Mechanisms of Action - Initially these drugs reduce the plasma volume and cardiac output. Long term effect of these drugs are decrease in total peripheral vascular resistance.
The Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure recommends most people try thiazide diuretics as the first-line drug treatment for hypertension and heart problems related to high blood pressure.
If diuretics are not able to lower your blood pressure, then your doctor may recommend additional hypertension medications to lower your blood pressure.
The British Hypertension Society recommends thiazide-type diuretic or calcium channel blocker as the first-line therapy in patients over 55 years.
Various studies suggest low dose thiazide-type diuretic as the first-line therapy for hypertension patients.
Because of the effectiveness of thiazide diuretics as an antihypertensive, they are the first-line of treatment for most patients with hypertension.
These drugs do reduce blood pressure by increasing urine production; this also promotes excretion of more than the normal quantity of sodium, potassium, and magnesium. It leads to these mineral deficiencies. To avoid this, you should take potassium and magnesium rich foods.
Thiazide diuretics lowered mortality and morbidity from stroke, heart attack, and heart failure more than beta blockers.
Who should avoid diuretics? Avoid diuretics, if you are breastfeeding women (it may pass into the breast milk), problems making urine, kidney or liver problems, and pregnant women. You should discuss with the doctor regarding the risks of using diuretics.
Advantages of this drug - Least expensive antihypertensive drugs. Best drug for treatment of systolic hypertension and for hypertension in the elderly. Can be combined with all other antihypertensive drugs to produce synergetic effect.
Is diuretic induce hyperglycemia?
Prolonged high-dose thiazide diuretic therapy can cause glucose intolerance and may occasionally lead to diabetes mellitus.
Short-term metabolic & epidemiologic studies and various clinical trials suggest a connection between thiazide diuretic use and the development of type 2 diabetes. However, in another review of the placebo-controlled hypertension trials with diuretics, there was only about 1% increase in new-onset diabetes compared with placebo.
The results are controversial, we hope diuretic-induced glucose intolerance is dose-dependent, it is less common with loop diuretics, and not noted among spironolactone use. And it is reversible on withdrawal of the agent.
How does loop diuretics cause hypokalemia?
Loop and thiazide diuretics get rid of water, sodium, and potassium from the body. This increased potassium loss can potentially cause hypokalemia.
Thiazide and loop diuretics can cause potassium loss from the blood, which leads to abnormal heart rhythms. If it happens to you, then eat potassium rich foods, a potassium supplement, or take a potassium-sparing diuretic.
Can diuretics worsen gout?
Thiazide and loop diuretics have shown to increase your serum urate levels, thus increased your risk of gout.
Water pills removes the excess water from your body, this causes increased uric acid levels. If you have never had gout and using diuretics for hypertension treatment, you are at risk of developing gout. Diuretics reduce urate excretion and increase its reabsorption; the effect is dose dependent.
Types of diuretics
There are three types of diuretic medications, they are thiazide, loop, and potassium-sparing diuretics.
Thiazides are the most commonly prescribed diuretics used to treat high blood pressure. These drugs decrease fluids in your body as well as relax your blood vessels.
Commonly available thiazides diuretics are:
- Chlorothiazide (brand name: Diuril),
- Chlorthalidone (brand name: Thalitone),
- Hydrochlorothiazide (brand name: Esidrix, Microzide & Oretic),
- Metolazone (brand name: Zaroxolyn), indapamide (brand name: Lozol),
- Bendroflumethiazide (brand name: Aprinox, Bendroflumethiazide, Bendroflumethiazide BP & Prestim).
Loop diuretics are often used to treat a hypertensive patient with heart failure.
Commonly available loop diuretics are:
- Torsemide (brand name: Demadex), furosemide (brand name: Lasix),
- Bumetanide (brand name: Bumex),
- Ethacrynic acid (brand name: Edecrin).
All diuretic except potassium-sparing diuretics cause you to lose potassium; this can lead to arrhythmia. These diuretics reduce fluid levels in your body without losing potassium. Potassium-sparing diuretics may prescribe for people at risk of low potassium levels. This diuretic is less effective in reducing your blood pressure as compared to other diuretics. Thus doctors prescribe it with another hypertension drug.
Commonly available potassium-sparing diuretics are:
- Amiloride (brand name: Midamar),
- Spironolactone (brand name: Aldactone),
- Triamterene (brand name: Dyrenium),
- Eplerenone (brand name: Inspra).
Commonly available diuretic combinations are:
- Amiloride hydrochloride + hydrochlorothiazide (brand name: Moduretic),
- Spironolactone + hydrochlorothiazide (brand name: Aldactazide),
- Triamterene + hydrochlorothiazide (brand name: Dyazide & Maxzide).
What are the side effects of diuretics?
It is a good idea to avoid these drugs if you have a history of diabetes or gout.
Low blood potassium level, high potassium level (if on potassium-sparing diuretics), low sodium levels, and increased blood sugar level. Other side effects are a headache, dizziness, thirst, muscle cramps, increased cholesterol level, skin rash, blood uric acid, gout, diarrhea, frequent urination, stomach upset, interfere with calcium metabolism, hormonal issues, and impotence (22%).
Metabolic side effects are (uncommon with small doses) hypokalemia, hypomagnesaemia, hypernatremia, hyperuricemia, dyslipidemia (increased total and LDL cholesterol), impaired glucose tolerance, and hyperkalemia (with thiazides).
What are the warning signs of diuretic?
Consult a doctor immediately if you are having: heavy rash, breathing or swallowing problems, and Hyperuricemia (Gout).