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# Managing medications and blood pressure to avoid shock in the elderly
- URL: https://www.foodconsumer.org/managing_medications_and_blood_pressure_0118111243/
- Published: 2011-01-18T13:42:00.000Z
- Updated: 2026-09-22T15:58:47.000Z
- Description: Ontario patients over 66 taking calcium-channel blockers faced about six times the risk of hospitalization for low blood pressure or shock when also given erythromycin, and four times with clarithromycin. Azithromycin showed no added risk, so the authors prefer it.
- Author: Food Consumer
- Tags: Healthcare, Health News, #vivvo-import

The combination of antibiotics with blood pressure drugs could cause life-threatening complications.

A rapid drop in blood pressure, known as hypotension, can lead to shock could affect older patients according to new research published in Canadian Medical Association Journal.

Low blood pressure, also called hypotension, can cause dizziness and fainting - increasing the risk of fall related injuries in the elderly. It can also be a symptom of a serious heart, endocrine or neurological disorder according to the Mayo clinic. Severely low blood pressure can deprive the brain and other vital organs of oxygen and nutrients, leading to shock. The causes of low blood pressure can range from dehydration to problems with the way your brain signals your heart to pump blood. 

In this study researchers recruited Ontarians over age 66 taking calcium-channel blockers to treat blood pressure.

Nearly 7100 patients were documented as hospitalized for low blood pressure or shock after taking antibiotic.

Dr. David Juurlink, a Scientist at the Sunnybrook Research Institute and the Institute for Clinical Evaluative Sciences, says macrolide antibiotics can cause drug interactions.

Results showed treatment with erythromycin increased the risk of low blood pressure about 6-fold and clarithromycin increased 4-fold. 

However, azithromycin did not increase the risk of shock at all.

Erythromycin and clarithromycin are also linked to an increase the risk of hypertention, or a rise in blood pressure, making azithromycin the preferential treatment for patients receiving a calcium channel blocker, the authors suggested.

According to Medscape Today, the age-related physiological decline in kidney function, often exacerbated by the deleterious renal effects of diabetes mellitus, congestive heart failure, and hypertension, substantially influences the excretion of numerous antibiotics. This predisposes elderly patients to a risk of antibiotic-induced toxicity including aminoglycoside-induced nephrotoxicity and ototoxicity, antibiotic-associated pseudomembranous colitis, trimethoprims and sulfamethoxazale-induced blood dyscrasias and hyperkalemia, quinolone-related seizures, doxycycline- related esophageal ulcers and structures, and acute liver injury secondary to prolonged therapy with amoxicillin and clavulanic acid.

Current guidelines say normal blood pressure as equal to or lower than 120/80\. Many doctors think 115/75 is optimal.

According to the Mayo clinic medical team, low blood pressure as readings lower than 90 systolic or 60 diastolic. Either number in the low range and your blood pressure can be considered lower than normal. 

Athletes and people who exercise regularly tend to have lower blood pressure and a slower heart rate than do people who aren't as fit. In general, so do non-smokers and people who eat well and maintain a normal body weight. 

Stephen Lau and editing by Aimee Keenan-Greene