Superintendent pharmacist Robert Bradshaw of Oxford Online Pharmacy has issued a warning to the millions of people in the UK who take beta blockers and diuretics for high blood pressure, as the country braces for a significant heatwave with temperatures expected to exceed 35C and reach up to 38C in some areas.
Heatwave Alert and Medication Risks
The Met Office has issued an Amber Extreme Heat Warning from Monday through Thursday, with temperatures widely exceeding 35C. According to the British Heart Foundation, over 50 million prescriptions for beta blockers are issued annually in the UK, with approximately two million people using them to control hypertension and other circulatory problems. Diuretics are also routinely prescribed for conditions including heart failure and high blood pressure, often alongside beta blockers.
Bradshaw cautioned: "High temperatures and humidity can be a bad combination for anyone who suffers from high blood pressure, as the hot weather causes the heart to beat faster, circulating twice as much blood around the body. Also, some blood pressure medications like beta blockers and diuretics can affect the body's ability to stay hydrated or respond to high temperatures."
Health Risks During Extreme Heat
As temperatures rise, the body must work harder to maintain a normal core temperature, placing additional strain on the heart, lungs, and kidneys. This heightens the risk for those already living with a heart condition. The British Heart Foundation warns: "If you use a GTN spray to control your angina, you should take extra care in hot weather. GTN spray can dilate your blood vessels quickly, which causes your blood pressure to suddenly drop and you may feel faint."
The charity also advises: "It's particularly important to stay cool if you have heart failure - where your heart doesn't pump blood around your body as well as it should. If you've been told to restrict your fluid intake, speak to your GP about other ways to keep cool during summer. If you take water tablets and are dizzy or light headed let your doctor know. Your medication can then be reviewed or adapted as necessary."
Precautions and Symptoms to Watch For
Bradshaw urges anyone with a history of high blood pressure to consume plenty of fluids to stay hydrated, seek shade and remain in a cool environment whenever possible, and wear a hat when outdoors. He added: "You should also monitor your blood pressure regularly during the heatwave. If it's high or you are experiencing any worrying symptoms like extreme tiredness or confusion, a rapid pulse, excessive sweating, headaches, swelling in your arms and legs or nausea, seek urgent emergency medical advice."
Warning signs of heat stroke include sweating, cold and clammy skin, dizziness, fainting, muscle cramps, heat rash, swelling in the ankles, rapid or shallow breathing, nausea, and vomiting. If heat stroke is suspected, immediate medical attention is necessary.
