Cartia XT is commonly prescribed for treating high blood pressure and specific types of angina. By slowing down the rate at which calcium moves into your heart and blood vessel walls, the medicine can help lower blood pressure and make it easier for the heart to pump blood. Some of the dosage forms listed on this page may not apply to the brand name Cartia XT. In Summary More frequent side effects include: dizziness, edema, asthenia, headache, and vasodilatation. You should not use Cartia XT if you have very low blood pressure, a serious heart condition such as sick sinus syndrome or AV block (unless you have a pacemaker), or if you have recently had a heart attack and you have a build-up of fluid in your lungs. Learn about side effects and possible interactions when taking Cartia XT (Generic Cardizem CD) Cartia XT (diltiazem hydrochloride) Extended-Release is a calcium channel blocker used to treat hypertension (high blood pressure), angina (chest pain), and certain heart rhythm disorders. Summary. Headache is found among people who take Cartia xt, especially for people who are female, 60+ old , have been taking the drug for 1 month, also take medication Lasix, and have Primary pulmonary hypertension. What causes dizziness and headache after taking Cartia?.I was diagnosed with Afib and out on Cartia extended release 120 mg and Xarelto. I had severe dizziness and headaches and my pulse dropped to 48. I am on Cartia XT for shortness of breath and chest pains but have a bad headache. Can I take something for the - Answered by a verified Health Professional How to use Cartia XT. Take this medication by mouth with or without food, usually once daily or as directed by your doctor. Swallow the capsules whole.