Heart patients need to lower dosage in summer

Sun, May 11 12:05 AM

Sonal Chandra, 53, fainted while shopping one afternoon last week. Since she had high blood pressure, her family suspected a mild heart attack and rushed her to a cardiologist.

They were surprised when the doctor did not add to her medication. "He actually reduced my hypertension medication and explained that since heat lowers blood pressure naturally, medicines to lower blood pressure can make become too low," says Chandra.

People taking medicines to lower their blood pressure often need to re-adjust their dose in very hot weather. "Any kind of extreme weather is bad for people on heart medication.

Just as the cold constricts blood vessels and raises risk of heart attacks, the heat dilates the blood vessels, making blood pressure fall lower than 120/80, making people feel feel lightheaded, dizzy or faint," says Dr Ashok Seth, chairman and chief cardiologist, Max Heart and Vascular Institute. "A combination of cardiovascular drugs, such as diuretics, vasoconstrictors and beta blockers, can further impair the body's ability to regulate heat and expose them to heat stroke by making the body lose water, slow sweat production or restrict blood flow to the skin, impairing the body's ability to release heat," says Dr Purshotam Lal, chief cardiologist, Metro Group of Hospitals.

Diuretics lower blood pressure by taking fluid out of the body and raise the risk of dehydration and in hot summer months, cardiologists may need to replace diuretics with ACE inhibitors or beta blockers, which lower blood pressure by different mechanisms. These drugs, however, may have some cons.

"Some heart medication that causer rashes or pigmentation on direct exposure to sunlight, so patients must avoid the sun in peak summer and if they can't, find out if their prescription needs to be changed," says Dr Seth. Excessive alcohol use can also increase risk for heat stroke as it causes the body to excrete water, leading to dehydration.

Other medicines such as antihistamines (for allergies), phenothiazines (tranquilizers), tricyclic antidepressants and anti-cholinergics (used to treat Parkinson's disease) impair the body's ability to regulate temperature. Since the elderly usually have multiple health problems, they are more likely to be taking more than one medication that can affects their body's natural cooling ability.

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