Treating CVD: benefits and risks of drugs

Lowering blood pressure and cholesterol

• Antihypertensives lower blood pressure. Types include diuretics (increase urine output, reducing blood volume), beta blockers (reduce heart rate and force of contraction), ACE inhibitors and calcium channel blockers (widen blood vessels). Risks: dizziness, fainting, tiredness; blood pressure may fall too low.
• Statins lower blood LDL cholesterol by inhibiting an enzyme the liver uses to make cholesterol. Risks: muscle aches and, rarely, liver damage; they must be taken long term.

Reducing clotting

• Anticoagulants (such as warfarin and heparin) interfere with the clotting cascade, so clots are less likely to form. Risk: excessive bleeding; warfarin dose needs careful monitoring.
• Platelet inhibitors (such as aspirin and clopidogrel) stop platelets sticking together and to damaged walls. Risks: bleeding, and aspirin can irritate the stomach lining and cause ulcers.

Weighing it up

A doctor balances a patient's risk of a heart attack or stroke against the side effects and the risks of other conditions (for example bleeding risk in someone with stomach ulcers). Lifestyle changes are recommended alongside drugs.

Worked example

Why might a doctor not prescribe aspirin to a patient with a stomach ulcer?

1. Aspirin is a platelet inhibitor, so it increases bleeding risk.
2. It also irritates the stomach lining.

Answer: The ulcer could bleed more and worsen, so the risk may outweigh the benefit.

Check yourself

1. How do statins reduce CVD risk?
   • They stop platelets sticking together
   • They widen arteries directly
   • They reduce cholesterol production in the liver, lowering LDL
   • They increase blood clotting
   Show answer

   They reduce cholesterol production in the liver, lowering LDL. Statins inhibit an enzyme in cholesterol synthesis.

2. What is the main risk of anticoagulants such as warfarin?
   • Excessive bleeding
   • High blood pressure
   • Raised LDL
   • Increased clot formation
   Show answer

   Excessive bleeding. Reducing clotting means wounds and internal bleeds may not stop.

3. Which drug is a platelet inhibitor?
   • A statin
   • A diuretic
   • Aspirin
   • A beta blocker
   Show answer

   Aspirin. Aspirin reduces platelet clumping.

4. A patient's main problem is high blood pressure. Which group of drugs is most suitable?
   • Statins
   • Antihypertensives
   • Anticoagulants
   • Antibiotics
   Show answer

   Antihypertensives. Antihypertensives lower blood pressure.

5. How does a diuretic lower blood pressure?
   • It speeds up the heart
   • It lowers LDL
   • It breaks down clots
   • It increases urine output, reducing blood volume
   Show answer

   It increases urine output, reducing blood volume. Less blood volume means lower pressure.

6. Which is a possible side effect of statins?
   • Excessive bleeding
   • Muscle aches
   • Stomach ulcers from platelet inhibition
   • Increased blood volume
   Show answer

   Muscle aches. Muscle pain is a known side effect of statins.

Practise with instant feedback Print this lesson

Sources

• Pearson Edexcel International Advanced Level in Biology specification (XBI11/YBI11, first teaching 2018)

Last updated 7 November 2026. Spotted a mistake? Tell us.