Drug Uses Cardizem is used to treat rhythm disturbances of the heart like supraventricular tachycardia, atrial fibrillation and flutter. It might also be used by your doctor in other cases as he deems fit. Usage Following the dosage instructions of your doctor is the best way to use any medication. If you are unsure or do not remember the instructions then you may read the medicine label for more detailed information. Missed Dose Despite your best attempts at remembering, if you still miss out on a dose, then take it as soon as you remember about it. But keep in mind that you will have to adjust your next dose by spacing it out by 4 to 5 hours. If this is not possible, then the best thing to do would be to skip the missed dose and continue with your normal dosage schedule. Never try to compensate for the missed dose by taking a double dose together. It may cause adverse effects. Storage Store Cardizem at room temperature (read medicine label if unsure). Always keep it in a cool dark place that is not directly exposed to sources of heat or moisture and sunlight. Protect it from kids and pets. Overdose An overdose of Cardizem may have adverse effects that require immediate medical attention. Contact the nearest emergency poison control center immediately if you notice effects like confusion, shortness of breath especially while lying down, drowsiness, fainting and slow heart rate.