The five main classes of blood pressure medication
Blood pressure medications are not all the same. They target different mechanisms that regulate blood pressure. Your doctor selects a medication class based on your age, ethnicity, other health conditions, and whether you have had side effects from previous medications. Understanding how each class works helps you have informed conversations with your doctor and recognize what side effects to expect.
1. ACE inhibitors
How they work: ACE (angiotensin-converting enzyme) inhibitors block an enzyme that produces angiotensin II, a hormone that narrows blood vessels. When blood vessels relax and widen, blood pressure drops.
Common Australian brand names: Perindopril (Coversyl), Ramipril (Tritace, Ramace), Enalapril (Renitec), Quinapril (Accupril), Lisinopril (Prinivil), Fosinopril, Trandolapril
Who they are best for: People with diabetes, chronic kidney disease, or heart failure. ACE inhibitors protect kidney function and reduce protein loss in urine. They are often the first choice for younger adults.
Common side effects: Persistent dry cough (affects 10-15% of users), dizziness when standing up, elevated potassium levels, rarely angioedema (swelling of the face or throat, which requires immediate medical attention).
PBS availability: Yes, all ACE inhibitors are PBS-listed. Most cost $25 per script ($7.70 with concession card).
2. Angiotensin receptor blockers (ARBs)
How they work: ARBs block the receptor where angiotensin II binds, achieving the same result as ACE inhibitors but through a different pathway. They do not cause the cough that ACE inhibitors do.
Common Australian brand names: Irbesartan (Avapro, Karvea), Candesartan (Atacand), Telmisartan (Micardis), Olmesartan (Olmetec), Valsartan (Diovan), Losartan (Cozaar)
Who they are best for: People who cannot tolerate ACE inhibitors due to cough. ARBs are equally effective for kidney protection and heart failure. They are a good alternative for people with diabetes or chronic kidney disease.
Common side effects: Dizziness, elevated potassium (less common than with ACE inhibitors), rarely low blood pressure. ARBs generally have fewer side effects than other classes and are well tolerated.
PBS availability: Yes, all major ARBs are PBS-listed.
3. Calcium channel blockers
How they work: These medications prevent calcium from entering the muscle cells of blood vessels and the heart. Without calcium, blood vessels cannot contract as forcefully, so they relax and blood pressure drops.
Common Australian brand names: Amlodipine (Norvasc), Felodipine (Plendil), Lercanidipine (Zanidip), Nifedipine (Adalat), Diltiazem (Cardizem), Verapamil (Isoptin)
Who they are best for: Older adults and people of African or Caribbean descent, who often respond better to calcium channel blockers than to ACE inhibitors or ARBs. Also used for people with angina (chest pain) or certain heart rhythm problems.
Common side effects: Ankle swelling (especially with amlodipine), flushing, headache, dizziness, constipation (more common with verapamil). The ankle swelling is cosmetic and not dangerous but can be bothersome.
PBS availability: Yes, all are PBS-listed.
Grapefruit interaction
4. Beta blockers
How they work: Beta blockers block the effects of adrenaline on the heart and blood vessels. They slow the heart rate, reduce the force of heart contractions, and lower the amount of blood the heart pumps per minute. This reduces the pressure on artery walls.
Common Australian brand names: Metoprolol (Betaloc, Metoprolol Sandoz), Atenolol (Tenormin), Bisoprolol (Bicor), Carvedilol (Dilatrend), Nebivolol (Nebilet), Propranolol (Inderal)
Who they are best for: People who have had a heart attack, have heart failure, or have certain heart rhythm problems. Beta blockers are no longer the first choice for uncomplicated hypertension but are essential if you have existing heart disease.
Common side effects: Fatigue, cold hands and feet, slower heart rate, difficulty sleeping, vivid dreams. Beta blockers can mask symptoms of low blood sugar in people with diabetes and may worsen asthma or COPD in some individuals.
PBS availability: Yes, all beta blockers are PBS-listed.
5. Diuretics (water pills)
How they work: Diuretics help the kidneys remove sodium and water from the body through urine. Reducing fluid volume lowers the amount of blood flowing through blood vessels, which reduces pressure on artery walls.
Common Australian brand names: Hydrochlorothiazide (HCT, Dithiazide), Indapamide (Natrilix), Chlorthalidone, Frusemide (Lasix), Spironolactone (Aldactone), Amiloride
Who they are best for: Older adults, people of African or Caribbean descent, and people with heart failure or swelling. Diuretics are often combined with ACE inhibitors or ARBs for better blood pressure control.
Common side effects: Increased urination (especially in the first few weeks), low potassium (with thiazide or loop diuretics), elevated potassium (with spironolactone or amiloride), dizziness, increased blood sugar and cholesterol with long-term use.
PBS availability: Yes, all are PBS-listed.
Comparing the five medication classes
| Class | How It Works | Best For | Common Side Effects | PBS Listed |
|---|---|---|---|---|
| ACE inhibitors | Block angiotensin II production; relax blood vessels | Diabetes, kidney disease, heart failure, younger adults | Dry cough, dizziness, elevated potassium | Yes |
| ARBs | Block angiotensin II receptor; relax blood vessels | Same as ACE inhibitors; alternative for those with cough | Dizziness, elevated potassium (rare) | Yes |
| Calcium channel blockers | Prevent calcium entry into vessel walls; relax arteries | Older adults, African/Caribbean descent, angina | Ankle swelling, flushing, headache | Yes |
| Beta blockers | Block adrenaline; slow heart rate and reduce force | Post-heart attack, heart failure, rhythm problems | Fatigue, cold extremities, slow heart rate | Yes |
| Diuretics | Remove sodium and water through kidneys; reduce fluid volume | Older adults, heart failure, fluid retention | Increased urination, low/high potassium, dizziness | Yes |
PBS costs and access in Australia
Most blood pressure medications are listed on the Pharmaceutical Benefits Scheme (PBS), which subsidizes the cost for Australian residents with a Medicare card. As of January 2026, the government reduced the general co-payment to make medications more affordable.
Current PBS co-payment amounts (2026)
- General patients: $25.00 per prescription (reduced from $31.60)
- Concession card holders: $7.70 per prescription
- PBS Safety Net: Once you spend $1,748.20 in a calendar year (general) or $277.20 (concession), further scripts are free or reduced for the rest of the year
If you take multiple blood pressure medications (which is common), you will pay the co-payment for each separate medication. Two-in-one combination pills (such as perindopril with amlodipine or irbesartan with hydrochlorothiazide) count as one prescription, which saves money and reduces the number of tablets you need to take each day.
Track your PBS Safety Net
When lifestyle changes are enough
Not everyone with elevated blood pressure needs medication immediately. If your blood pressure is in the stage 1 hypertension range (140-159 systolic or 90-99 diastolic) and you have no other cardiovascular risk factors, your doctor will typically recommend lifestyle changes first.
- Dietary changes: Reduce sodium to less than 2,000 mg per day. Follow the DASH diet, which is rich in fruits, vegetables, whole grains, and low-fat dairy. This can lower blood pressure by 8-14 mmHg.
- Exercise: Aim for 150 minutes per week of moderate aerobic activity (brisk walking, cycling, swimming). Regular exercise lowers blood pressure by 5-8 mmHg on average.
- Weight loss: Losing 5-10 kg can reduce systolic blood pressure by 5-20 mmHg if you are overweight or obese.
- Limit alcohol: No more than two standard drinks per day for men or one for women. Excess alcohol raises blood pressure.
- Quit smoking: Smoking does not directly cause chronic hypertension, but it damages blood vessels and increases cardiovascular risk. Quitting is essential.
- Manage stress: Chronic stress contributes to high blood pressure. Meditation, yoga, and adequate sleep can help.
If you make consistent lifestyle changes and blood pressure remains elevated after three to six months, medication is recommended. Waiting longer than six months to start medication when blood pressure is not responding to lifestyle changes increases your risk of stroke, heart attack, and kidney damage.
When medication is necessary immediately
Your doctor will recommend starting medication straight away (alongside lifestyle changes) if:
- Stage 2 hypertension: Systolic 160+ or diastolic 100+ mmHg. This level of blood pressure significantly increases cardiovascular risk, and medication should not be delayed.
- Existing cardiovascular disease: If you have had a heart attack, stroke, angina, heart failure, or peripheral artery disease, medication is essential regardless of blood pressure level.
- Diabetes: People with diabetes have a higher risk of cardiovascular complications. Target blood pressure is lower (130/80 or less), and medication is usually started if blood pressure is 140/90 or above.
- Chronic kidney disease: High blood pressure damages kidneys further. ACE inhibitors or ARBs are typically started to protect kidney function.
- High cardiovascular risk score: If your 10-year cardiovascular risk is above 15-20% (calculated using age, cholesterol, smoking status, and other factors), medication is recommended even if blood pressure is in the stage 1 range.
Combination therapy: why most people need more than one medication
About two-thirds of people with hypertension require two or more medications to achieve target blood pressure. Combination therapy is more effective than maxing out a single drug, and it causes fewer side effects because each medication can be used at a moderate dose.
Common two-drug combinations
| Combination | Why It Works | Australian Brand Examples |
|---|---|---|
| ACE inhibitor + diuretic | Diuretic reduces fluid; ACE inhibitor relaxes vessels; work synergistically | Coversyl Plus (perindopril + indapamide), Accupril HCT (quinapril + HCT) |
| ARB + diuretic | Same logic as ACE inhibitor + diuretic; reduces cough risk | Karvezide (irbesartan + HCT), CoAprovel (irbesartan + HCT) |
| ACE inhibitor + calcium channel blocker | Dual action on blood vessels from different angles; reduces ankle swelling from CCB | Coveram (perindopril + amlodipine), Exforge (valsartan + amlodipine) |
| ARB + calcium channel blocker | Same benefit as ACE inhibitor + CCB without cough risk | Exforge (valsartan + amlodipine), Twynsta (telmisartan + amlodipine) |
Combination pills improve adherence because you take one tablet instead of two or three separate medications. They are PBS-listed and cost the same as a single medication script.
Monitoring and adjusting medication
Starting blood pressure medication is not a one-and-done decision. Your doctor will:
- Review blood pressure after 4 weeks: It takes 2-4 weeks to see the full effect of a new medication or dose adjustment. Your doctor will check if blood pressure has reached target or if changes are needed.
- Adjust dose or add a second medication: If blood pressure is not controlled, your doctor will increase the dose or add a medication from a different class.
- Monitor for side effects: Most side effects appear in the first few weeks. If you have intolerable side effects, your doctor can switch you to a different class or combination.
- Check kidney function and electrolytes: ACE inhibitors, ARBs, and diuretics affect potassium levels. A blood test is typically done 1-2 weeks after starting these medications and then periodically.
- Home blood pressure monitoring: Your doctor may ask you to measure blood pressure at home using a validated device. Home readings are often more accurate than clinic readings and help detect white coat hypertension or masked hypertension.
Keep a record of your home blood pressure readings. Use a tracking app or notebook to log date, time, systolic, diastolic, and pulse. Bring this data to your appointments so your doctor can make informed decisions about your treatment.
Important warnings and precautions
Never stop medication suddenly
- Pregnancy: ACE inhibitors and ARBs are dangerous during pregnancy and can cause birth defects or fetal death. If you are planning pregnancy or become pregnant, tell your doctor immediately. Methyldopa, labetalol, or nifedipine are safer alternatives.
- Kidney function: All blood pressure medications can affect kidney function, especially in people with pre-existing kidney disease. Regular blood tests are necessary.
- Drug interactions: NSAIDs (ibuprofen, naproxen) reduce the effectiveness of blood pressure medications and can cause kidney problems. Use paracetamol for pain relief instead.
- Dehydration: Diuretics combined with vomiting, diarrhea, or excessive sweating can cause dangerous drops in blood pressure and electrolyte imbalances. Stay hydrated, especially in hot weather or during illness.
The bottom line
Blood pressure medication is one of the most effective interventions for reducing cardiovascular risk. The five main classes work through different mechanisms, and your doctor will select the best option for your specific situation. Most medications are PBS-listed and affordable, with the general co-payment now $25 per script.
Lifestyle changes should always be part of your treatment plan, even if you take medication. Combining medication with diet, exercise, weight loss, and stress management gives the best results and may allow you to reduce medication doses over time. Track your blood pressure at home, attend regular check-ups, and communicate openly with your doctor about side effects or concerns. Consistent treatment protects your heart, brain, and kidneys for the long term.
