The Treatment of Hypertension in Adults
1: Pathophysiology.
Hypertension also known as high blood pressure is persistently raised arterial blood pressure. Blood pressure is recorded by two figures χ/ϒ mmHg, where χ is the systolic pressure is the pressure in the arteries when the heart beats and forces blood around the body, and ϒ is the diastolic is the pressure at rest between heart beats. Hypertension is usually defined as having sustained blood pressure of 140/90mmHg or above. Readings below show which category patient falls within.
Hypertension can be seen to not be a disease but an essential modifiable risk factor of one of several diseases such as heart failure, myocardial infarction, worsening renal function and also along with increased blood pressure, the heart works harder to pump blood around the body, thus over time weakening it. Furthermore, the pressure can damage the walls of the arteries within the body, resulting in blockage or haemorrhage. Both can cause stroke. There are two types of hypertension, essential (primary) and secondary. Aetiology of both differentiates significantly. The common of the two is essential hypertension which has no identifiable cause (accounting for ~95% of people with hypertension) and the remainder being secondary which is due to an underlying cause such as kidney conditions, narrowing of the lumen in the artery, hormonal condition, Contraceptive pill and illegal substances. Lifestyle plays a significant role in regulating primary hypertension with such factors including age, alcohol consumption, diet, family history of cardiovascular disease, exercise, being Afro-Caribbean or South Asian origin, and salt intake. All these factors could affect a patient’s response to drug treatment. SYMPTOMS: chronic headaches that last for days, dizziness, blurry vision, drowsiness, nausea, shortness of breath, general fatigue, heart palpitations, flushed face and tinnitus. Drug therapy is given to pxs with persistent high BP of 160/100 mmHg or more, pxs at raised cardiovascular risk (10-year risk of CVD of 20% or more, existing CVD or target organ damage) , with persistent BP of more than 140/90 mmHg
Angiotensin-converting enzyme inhibitors (ACE i), work by preventing Angiotensin I converting to Angiotensin II - preventing vasoconstriction. The are absorbed and eliminated rapidly similar to Angiotension II receptor blockers (AII- RB) which act more like pro-drugs. Thiazide Diuretics provide vasodilation and increase the passing of fluids and sodium. Calcium channel receptor blockers (CCRB) relax vascular smooth muscle in the arteries by reducing amount of calcium within arteries allowing them to widen. Beta-blockers (β-blockers) block β – receptors on the heart to slow the heart rate down, controlling how blood is pumped around the body.
2: Pharmacoepidemiology.
Overall, 20% of the world’s population are estimated to have H (BP ≥140/90mmHg). It is estimated that just over 5.4 million people are being treated for essential H in England .Age:The prevalence of H increases with age. The Health Survey for England reported the prevalence of H to be 3.3% in those <40 years, 27.9% in those aged 40-79 years and 49.9% in those aged over 80 years. Systolic H is age related and systolic BP rises throughout life span while diastolic BP remains constant or declines after fourth decade. Ethnicity - Black people tend to develop H at an earlier age, and target organ damage differs from that in white people. The first study, in 1964 to compare the renin-angiotensin system in black and white hypertensive people reported that 30% of black people with H had no detectable plasma renin activity. It has also been seen that black people have poor response to tx with ACE I and βB. Sex:The third national health and nutrition examination survey found the prevalence of H to be 12% for white men and 5% for white women aged 18-49 years. The survey also found that by the age of 70, the prevalence of H in