Beta blocker

These medicines have been used in cardiology since the middle of the 1960s. These medicines reduce blood pressure and are indicated to treat heart failure, angina pectoris, hypertension, myocardial infarction, and episodes of tachycardia etc. Beta blockers and diuretics are still the treatments of choice forInhypertension.

How do beta blockers work?

Their main method of action is to reduce the activity of the nervous system. After an initial latent period, they reduce hypertension through complex mechanisms of reducing heart rate and inhibiting secretion of renin, an enzyme required for the formation of angiotensin II. The anti-hypertensive effect of these medicines is obtained at low doses.

Do they have contraindications or do they need precautions for use?

These medicines can cause weakness, cold extremities (Raynaud's disease), bradycardia (abnormal slowing of the heart rate), gastro-intestinal problems (diarrhoea, epigastric pain, nausea or vomiting), and reduced physical performance during exercise.

Sources :

• Merck Manual – 4^th edition
• Comité français de lutte contre l'hypertension artérielle (French hypertension committee), website accessed on 17 June 2011
• Pharmacorama, website accessed on 17 June 2011