All About Antihypertensive Series 4 – Diuretics

Hello all nursing students there,

This is the fourth topic in All About Antihypertensive Series… You can read other topics in this series here… Diuretics are primarily those drugs help in the diuresis or increased production of urine. These drugs mainly affect the renal mechanism for tubular secretion and reabsorption of water and electrolytes. Diuretics are classified as follows

Classification and Examples

Thiazide and Thiazide-like diuretics

  • Chlorothiazide
  • Hydrochlorothiazide
  • Metolazone
  • Chlorthalidone
  • Indapamide

Last two are the examples for Thiazide-like diuretics.

Loop Diuretics

  • Furosemide
  • Torsemide
  • Bumetanide

Potassium-sparing Diuretics

  • Amiloride
  • Spironolactone
  • Triamterene

Osmotic Diuretics

  • Mannitol

Carbonic Anhydrase Inhibitors

  • Acetazolamide
  • Methazolamide

Mechanism of  action

The action of the diuretics varies depending on the agents. Generally, all affect on the renal mechanism for tubular secretion and reabsorption and enhance the selective excretion of various electrolytes and water.

In the management of hypertension, the diuretic of choice is the Thiazide and the Thiazide-like diuretics and the loop diuretics. Other groups have only a weak Antihypertensive property and are used in different conditions too. For instance, potassium-sparing diuretics are to conserve potassium in patients receiving  Thiazide and loop diuretics, whereas, osmotic diuretics are a major choice in treating cerebral edema.

Contraindications

  • Hypersensitivity
  • Sulfa agents allergies
  • Gout
  • Pregnancy

Adverse effects

Thiazide and loop diuretics have the following side effects

  • Orthostatic hypotension
  • Metabolic alkalosis
  • Ototoxicity
  • They decrease levels of Na+, K+, and Mg+
  • They increase the levels of serum calcium, uric acid, glucose, cholesterol, and triglycerides

potassium-sparing diuretics specially Triamterene has the following side effects

  • Nausea
  • Flatulence
  • Skin Rashes
  • Nephrolithiasis

Drug Interactions

  • Additive hypokalemia with CORTICOSTEROIDS
  • Additive Hypotension with OTHER ANTIHYPERTENSIVES
  • Hyperkalemia with potassium-sparing diuretics and  ACEIs, ARBs, or Aliskiren
  • Lithium toxicity with potassium-sparing diuretics and LITHIUM as the combo reduce lithium excretion.

Nursing considerations

  • Fluid status must be monitored by, daily weight checks, maintenance of I/O chart, and assessment for any edema, lung sounds, skin turgor, and condition of the mucous membrane.
  • Assess any electrolyte imbalances by assessing for anorexia, muscle weakness, numbness, confusion, excessive thirst
  • Monitor pulse and BP before and during the therapy
  • Monitor lab values for electrolytes, especially K+, blood glucose, BUN, serum uric acid.
  • Administer oral diuretics in the morning to prevent sleep disturbances
  • Instruct to continue the Antihypertensive dose as prescribed even if the symptoms relieved.
  • Advise to change positions slowly to manage Orthostatic hypotension
  • Instruct to monitor weight weekly and to report significant changes.
  • Teach self-monitoring of pulse and BP
  • Caution on photosensitive reactions -instruct to use protective clothing and to use protective sunscreens

Hope you find it easy to follow and useful. Give your suggestions for further improvement…

Have a concentrated study time…

All About Antihypertensive series 3 – Calcium channel blockers, CCBs

Hi to all student nurses…

This is the 3rd topic in the All about Antihypertensive series. Calcium Channel Blockers or Calcium antagonist are drugs with multiple roles, which makes it the most widely used cardiovascular medicine. This multifunction (which you can find below) property makes these drugs effective not only in hypertension but also in angina, cardiac arrhythmias, some type of a headache etc.

Examples

CCBs includes drugs in three classes

  1. Phenylalkylamines ( verapamil)
  2. Benzothiazepines ( Diltiazem)
  3. Dihydropyridines ( Nifedipine and other alike drugs with the suffix  -dipine)

sometimes, phenylalkylamines and Benzothiazepines together is known under the class Nondihydropyridines

How CCBs act ( mechanism of action) 

These drugs inhibit or block the flow of extracellular  Ca2+ ions through the “L- type” Ca2+ channel, that is located on the vascular smooth muscles. This blocking results in the relaxation of smooth muscle cells, resulting in vasodilation and lowering of BP.

  • L-type Ca2+ channels, located on vascular smooth muscles, cardiac myocytes, and nodal tissue (SA and AV node). It regulates Ca2+ influx into the muscle cells and stimulates smooth muscle and cardiac myocytes contraction .once these channels are blocked,
  • Vascular smooth muscle relaxation – Vasodilation
  • Decrease myocardial force generation –  -ve inotropy
  • Decrease heart rate –  -ve chronotrophy
  • Decrease conduction velocity within the heart –  -ve dromotrophy

(If we consider the calcium channel as a mountain passage and the membrane as the mountain itself, CCBs act as a closed check post preventing the entry of ca2+ ions into the cells.)

CCBs

Indications

Mainly used in the following  cases

  1. Hypertension
  2. Arrhythmia
  3. Angina
  4. Raynaud’s disease
  5. Cluster headache.

Contraindications

  • Hypersensitivity
  • Pregnancy and lactation

Side Effects

Serious side effects are rare for CCBs. Major side effects may include-

  • Flushing
  • Headaches
  • Hypotension
  • Peripheral oedemas
  • Bradycardia

Grapefruit intake is not recommended along with CCBs, as it alters the effects of the drug.

Beta blockers are not given with CCBs, as both groups depress cardiac electrical and mechanical activities 

Nursing Considerations

  • Monitor BP and pulse before therapy, and in between the therapy
  • Monitor ECG periodically for prolonged period  therapy
  • Administer along with meals or milk to reduce the gastric irritation
  • Teach the patient self-monitoring of  Pulse and BP, and ask to inform any alteration
  • Advise to change position slowly to minimize the effects of Orthostatic hypotension.
  • Advise to inform any signs of side effects

These are the important points in CCBs. Have a happy and enthusiastic study time.

 

All About Antihypertensive Drugs Series-1-ACE INHIBITORS

Hello dear all nursing students…

Thought to share with you the different categories of antihypertensive drugs in the simplest way (the way which I think would help in your exams). This topic is divided into various series under the headline – All about Antihypertensive Drugs Series… In this very first series, I will give you some notes on ACE inhibitors.

ACE INHIBITORS (prils suffix group)

These are the most widely prescribed Antihypertensive agents. This group includes the drugs with – pril suffix.

Examples of ACE inhibitors

  1. Captopril ( Capoten)
  2. Enalapril ( Vasotec)
  3. Lisinopril ( Zestril)
  4. Ramipril ( Tritace)

HOW ACE INHIBITORS ACT

* As the name indicates, the fundamental action of these drugs is the inhibition or blocking of Angiotensin Converting Enzyme, which is responsible for the convention of Angiotensin I to Angiotensin II in the Renin-Angiotensin-Aldosterone mechanism, thus prevent Aldosterone release and its effects.

ACE inhibitors ———-> prevent AT II production —-> results in

  1. No Aldosterone release
  2. Eliminate sodium ions
  3. Retain potassium ions
  4. Decrease peripheral arterial resistance
  5. overall, Decrease in BP and Blood Volume

INDICATIONS (When it is used)

* Hypertension – Primary use is to decrease BP

* Congestive Heart Failure (CHF) – In combination with diuretics and digitalis for the overall improvement of the patient

* Ischemic Heart Disease – To reduce the risk of attack and stroke

* Diabetic Nephropathy – prevents progression of Nephropathy

CONTRAINDICATIONS

*Hypersensitivity

* Pregnancy

* Renovascular diseases

* Aortic stenosis

SIDE EFFECTS

* Hypotension

* Persistent dry cough

* Nausea

* Hyperkalemia

NURSING CONSIDERATIONS

* Closely monitor BP before and in between the administration. Systolic BP should be maintained > 80 mm of Hg.

* obtain baseline vital signs and lab reports of CBC, LFT, RFT, electrolytes, prior to treatment.

* First dose Hypotension management- an Initial dose of ACE inhibitors has the risk of 1st dose Hypotension. So, advise the patient to sit or lie down for 2 – 4 hours after the first dose.

* Orthostatic Hypotension management- Advise the patient to rise and change the position very slowly

* Teach the importance of withholding of potassium-sparing diuretics and other potassium supplements

* Advise reporting any of the signs and symptoms of side effects

* Explain to the patient that taste loss is expected for 2-3 months, and if it persists to notify the physician

BONUS NOTES

CAPTOPRIL

  • First ACE inhibitor
  • Only ACE inhibitor capable of passing Blood-Brain Barrier
  • Cause false positive result for urine acetone

ACE INHIBITORS – FLASH CARDS 

ACE Inhibitors Effects

DRUGS OF APRIL

INDICATIONS

CONTRAINDICATION

ACE Inhibitors NURSING considerations