Glucosamine and chondroitin may affect blood pressure, states Mayo Clinic. Glucosamine may cause heart palpitations and an irregular heart rate, and chondroitin may increase the heart rate. People with heart conditions or who take medications, supplements or herbs related to blood pressure should be cautious when using glucosamine and chondroitin.
Although glucosamine and chondroitin tend to be safe together or alone, some people may have adverse reactions to them, or they may not be effective for some people, according to WebMD. It is important to speak to a physician before taking glucosamine and chondroitin. People with shellfish allergies should be cautious when using glucosamine, as some glucosamine products contain shellfish.
Before taking glucosamine and chondroitin, it is important to make sure they do not interact with other medications, herbs or supplements, notes WebMD. Pregnant or nursing women should speak to a doctor before using glucosamine and chondroitin. Because the FDA does not regulate supplements the same way as medicines, it is important to be aware of potentially misleading claims.
The substances used in research studies may not be identical to the products found in stores, states WebMD. Some people may experience allergic reactions when taking glucosamine and chondroitin. Many health conditions may be worsened by glucosamine and chondroitin.