Topic 6

• Stages of developing a new drug/medicine

  1. Discovery of a drug

  2. Development in preclinical testing

  3. Development in clinical testing

  4. Drug approved by medical agency
• Discovery of a drug

  Scientists use their knowledge of how a disease works to find molecules that could be used to treat it
• Development in preclinical testing

  1. Test the drug on human cells/tissues in a lab

  2. Test drug on live animals – tests the drug works, find out if harmful and the best dosage
• Development in clinical testing

  1. Test the drug on healthy volunteers – check for harmful side effects when the body is working normally

  2. Test on patients with the illness – find the optimum dose which is the most effective with the fewest side effects

  3. Patients are randomly put into 2 groups – 1 is given the new drug, 1 is given a placebo (a substance which looks like the drug but doesn't do anything eg sugar pill)

  4. Blind clinical trial - the patient doesn't know whether they are getting the drug or the placebo

  5. Double-blind trials – neither patient or doctor knows if the patient is getting the drug or placebo
• Placebo effect

  When a patient expects the treatment will work and feels better, even though the treatment isn't doing anything
• Drug approved by medical agency

  When the drugs has passed all of these tests, it still needs to be approved by a medical agency before it can be used to treat patients
• Safety

  • This is important as some drugs are toxic, and have other side effects that might be harmful to people
• Effectiveness

  • This is also known as efficacy, and checks how well the drug cures the disease, or improves symptoms
• Dosage

  • This varies, and has to closely controlled, as too high a concentration might be toxic
• Lifestyle factors that may increase the risk of a non-communicable disease

  • Smoking
  • Diet and exercise
  • Alcohol
• Smoking

  Nicotine – increases heart rate -> increase blood pressure -> damage heart and blood vessels ->cardiovascular disease (CVD)
• Diet and exercise

  • Malnutrition – too many/few nutrients
  • High fat and sugar diet/lack of exercise is a risk factor for obesity
• Alcohol

  Increase risk of liver damage (cirrhosis – scarring of liver)
• Effects of non-communicable disease

  • Local - Pressure on local hospitals
  • National - If people with NCD can't work -> less money in country. Cost of treating people with NCD
  • Global - CVD is global number one cause of death
• Obesity

  • Diet high in fat and sugar
  • Large amount of fat stored under the skin and around vital organs such as the heart and kidneys
  • Fat is needed to cushion organs, store energy and vitamins
  • Too much fat increases the risk of some diseases including cardiovascular disease
• Waist-to-hip ratio

  • Abdominal fat is very closely linked to cardiovascular disease
  • Waist-to-hip ratio = waist circumference/hip circumference
  • Man above 1.0 = abdominal obesity
  • Woman above 0.85 = abdominal obesity
• How obesity is measured

  1. BMI = weight (kg) / height^2 (m^2)

  2. Assumes that the mass of other tissues is in proportion to height
• BMI calculation example

  BMI = 67/1.7^2 = 23
• Obesity is a form of malnutrition
• Diet and CVD (cardiovascular disease)

  1. Too much cholesterol causes fatty deposits to build up in the wall of the arteries

  2. Reduces the blood flow

  3. Cause high blood pressure and blood clots which block blood flow

  4. Cause heart attack or stroke
• Treat CVD and evaluate treatments

  1. Lifestyle changes - Exercise regularly, lose weight, stop smoking, low fat diet

  2. Drugs to reduce risk of stroke/heart attack - Statins reduce cholesterol in blood, Anticoagulants reduce chance of blood clots forming, Antihypertensives reduce blood pressure

  3. Surgery - Stent - tube inserted into arteries to widen/open, improve blood flow to heart muscles, Heart bypass - healthy blood vessel put in heart to let blood flow around blocked arteries, Heart transplant - heart replaced with donor heart (additional risk of rejection)