Certain cough suppressants such as dextromethorphan have the potential to raise your blood pressure. This happens because this drug causes your blood vessels to construct, which is the opposite of what lisinopril does. Because of this, all patients that have issues with blood pressure should ask their primary care physician
first before starting the medication. In the vast majority of cases, it is safe to take dextromethorphan for a few days while trying to get over a cold. A better option would be for you to schedule an appointment with your primary care physician so that you can discuss the safety of cold medications and so that other options can be explored. If cough is your primary symptom, then other medications such as guaifenesin may be more appropriate. If your cough continues for more than a week after contracting the cold, then you may need a steroid inhaler to calm down the inflammation in your lungs. If runny nose is your primary symptom, then you may benefit from an ipratropium nasal spray which won't raise your blood pressure. Since some of the options are by prescription only, your doctor
will have to see you first. Good luck.