Antihypertensive Drugs: Diuretics in a Nutshell

Bloodpressure cuff and bloodpressure meds

When talking about heart conductivity, the first thing that comes to mind is the rate in which the heart contracts – either too much or too little. If the heart is contracting at an increased, irregular, and uncontrollable speed, then what we usually give is a rate-control drug.

Rate-control drugs are your:

  • Beta-blockers
  • Calcium-channel blockers

These drugs affect the electro-excitability within the heart. Diuretics, on the other hand, do not work like that.

What are Diuretics?

In the simplest sense, diuretics are medications that primarily decrease the heart’s workload. Diuretics are medications that are designed specifically to eliminate increased amounts of salt and water inside the body by passing it out as urine. Diuretics that are mainly used for high blood pressure reduces the amount of fluid from the blood vessels which significantly decreases pressure within the vessels. While they are usually prescribed for high blood pressure, there are other conditions that diuretics can treat as well.

Antihypertensive Medications

When talking about diuretics for the heart, there is some pertinent information that you need to know. It can be quite confusing to identify the different kinds of antihypertensive medications. But, there is an easier way to pinpoint which is which; just do the ABCD; those letters stand for the following:

  • A – Ace Inhibitors, Angiotensin Receptor Blockers (ARBs)
  • B – Beta-blockers (rate-control drug)
  • C – Calcium-channel blockers (inhibit electrical stimulations)
  • D – Diuretics (bring down the volume)

Classifications of Diuretics

Think of it this way: diuretics causes diarrhea of the kidneys and the bladder. You are basically diuresing contents out of the body. So what are the different kinds of diuretics?

  1. Loop Diuretics (Furosemide, popularly known as Lasix)
  2. Thiazide Diuretics (Hydrochlorothiazide)
  3. Potassium-Sparing Diuretics (Spironolactone, Aldactone, “-tone”)
  4. Osmotic Diuretics (Mannitol)

To easily ascertain what kind of diuretics you’re encountering, just try to relate to the different suffixes mentioned since these are the most commonly used diuretics in a hospital setting:

  • Loop = Furosemide

Considered as the “big guns” when decreasing workload, loop diuretics are potassium-wasting diuretics; they are fast-acting and effectively take off fluid out of the vascular spaces into the potty and not the body.

  • Thiazide = Hydrochlorothiazide

Thiazides are the second string of potassium-wasting diuretics; think of it as the backup quarterback. This medication is quite effective but not as good as loop diuretics.

  • Potassium-Sparing = Spironolactone, Aldactone

Potassium-sparing diuretics block aldosterone which you can think of as Aldos “Tyrone”). So, Aldostyrone is a nightclub bouncer that stands at the door of your kidneys. He is that bouncer that prevents sodium from going out of the kidneys. Holding back sodium inside the kidneys will attract more water. Blocking Aldostyrone will allow sodium to leave the kidneys and water will instantaneously follow.

Since this type of diuretic is potassium-sparing, there is no need to educate your client about potassium-rich foods. Unlike your loop and thiazide diuretics that you are required to emphasize the need for increased potassium intake because they waste potassium out of the body.

  • Osmotic = Mannitol

Osmotic diuretics are your last line of drugs and are rarely given in hospital settings just because Furosemide is more popular and fast-acting. However, osmotic diuretics can also be provided to decrease blood pressure and volume inside the vascular system.

There you go, a very informative, concise, and useful way of identifying and remembering your antihypertensive diuretics. For other relevant nursing topics, you can head on to our website,