Is My Medication Affecting the Way My Heart Beats?

QT prolongation is a problem with the electrical signal in the heart that affects the heart’s rhythm. In some people, QT prolongation can create a feeling like the heart is racing. It can also make a person feel light-headed or dizzy, or they could suddenly faint. Others who have this electrical signal problem may not have any symptoms at all. There are many causes for QT prolongation, including some medications.

Problems with QT prolongation are more likely when people take multiple medications that can cause this effect. For some people, if steps are not taken to lower the risk, life-threatening heart problems can occur.

• Keep an up-to-date list of all the medications you take, including nonprescription and natural health products. Show this list to your health care providers each time you start a new medication or product.
• Use the 5 Questions to Ask (Change link after migration) to get information about side effects (including QT prolongation) of any medication or product you are taking, and any tests that you might need.
• Fill all your prescriptions at the same pharmacy so the pharmacist can see if you are taking more than one medication that causes QT prolongation. If you cannot fill a needed prescription at your usual pharmacy, share your updated medication list with both pharmacies.
• If you have started a new medication and experience any of the symptoms mentioned above, contact your health care provider.

This newsletter was developed in collaboration with patients and families.

Learning from consumer reports is shared with health care providers through ISMP Canada publications.