How Familiar Are You With Your Blood Pressure Pill?

How familiar are you with your blood pressure medication?

Maybe you are already experiencing some of the adverse effects yet you are still unaware that it is because of the drug.

If ever you are taking maintenance medication for high blood pressure, it is important to ask your doctor a number of questions before swallowing that pill.

Questions such as...


♥ What SIDE EFFECTS do you expect from taking the medication?

HOW FAST before you can see the effect (Onset of action)?

HOW LONG does the blood pressure control last in your body (Duration of action)?

HOW DOES IT actually WORK to lower your blood pressure (Mechanism of Action)?

As these are some of the frequently asked questions that I also encounter when I check patients at the clinic, I thought that it will be good to discuss them according to drug type and in simplified manner so that you can easily understand.

Although drug outcome for each individual varies, I will present the most common effects that majority go through in general.


1. VASODILATOR – Causes the smooth muscles of your blood vessel walls toRELAX. Widening of the blood vessel diameter leads to lower blood pressure.

  • Example: Hydralazine Hydrochloride

o Onset of Action – 1 to 2 hours

o Duration of Action – 3 to 8 hours

o Side Effects – Headache, Palpitation

2. BETA-BLOCKER – Decreases the workload of your heart by reducing the heart rate. Lower heart rate leads to lower blood pressure.

  • Example: Metoprolol

o Onset of Action – 1 to 2 hours

o Duration of Action – 3 to 6 hours

o Side Effects – Dizziness, Fatigue, Headache

o (other examples: Atenolol, Propranolol)

3. DIURETICEliminates excess salt and water from your body. Lesser body salt and water, lower blood pressure.

  • Example: Furosemide

o Onset of Action – 1/2 to 1 hour

o Duration of Action – 6 to 8 hours

o Side Effects – Dizziness, Decreased potassium, Headache, Increased uric acid

o (other examples: Hydrochlorothiazide, Indapamide, Spirinolactone)

4. CALCIUM CHANNEL BLOCKERDecreases calcium entry into your heart and arterial cells. Lower calcium entry into the heart and artery, lower blood pressure.

  • Example: Amlodipine

o Onset of Action – 24 hours

o Duration of Action – 24 hours

o Side Effects – Dizziness, Fatigue, Headache, Palpitation, Edema

o (other examples: Nifedipine, Felodipine, Verapamil)

5. ANGIOTENSIN CONVERTING ENZYME (ACE) INHIBITOR – Angiotensin is a chemical in your body that causes your blood vessels to become narrow. This type of drug inhibits the enzyme ACE from converting Angiotensin into the active form. Lower Angiotensin, lower blood pressure.

  • Examples: Captopril

o Onset of Action – 30 minutes

o Duration of Action – 8 to 12 hours

o Side Effects – Cough, Skin Rash, Allergy

o (other examples: Enalapril, Perindopril, Ramipril)

6. ANGIOTENSIN II RECEPTOR BLOCKERBlocks the receptor where Angiotensin binds to. No Angiotensin interaction with its receptor, lower blood pressure.

  • Examples: Losartan

o Onset of Action – 6 hours

o Duration of Action – 24 hours

o Side Effects – Cough, Fatigue, Dizziness

o (other examples: Telmisartan, Valsartan)

7. CENTRAL AGONIST – Stimulates nerve receptors in the brain that causes inhibition in release of Norepinephrine. Lower norepinephrine, lower sympathetic tone, lower blood pressure.

  • Examples: Clonidine

o Onset of Action – <1 hour

o Duration of Action – 6 to 10 hours

o Side Effects – Skin reactions, Dry mouth, Drowsiness, Fatigue

o (other example: Alpha Methyldopa)

These are the types and some examples of your blood pressure tablets in a nutshell.

If you are taking one, or perhaps two or more, be sure to always follow your doctor’s orders.

About the Author Alex Saroca MD

Alex Saroca is the founder of Tabachoy Academy. He is a general physician by profession, an author, a blogger, and an entrepreneur. He is on a mission to educate and make Filipinos realize - especially those with overweight, high blood pressure, and type 2 diabetes - that lifestyle modification is still more powerful than any drug in preventing heart disease, treating heart disease, and improving one's physical state and longevity.

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