Epinephrine is essential for the treatment of anaphylaxis. Patients with a history of severe allergic reactions should be instructed about the circumstances under which epinephrine should be used (See Section). It should be determined that the patient is at risk of future anaphylaxis, since there are some concerns in specific patients with epinephrine administration. (a) Epinephrine should be used with caution in patients with cardiac arrhythmias, coronary artery or organic heart disease, hypertension, or in patients who are on medications that may sensitize the heart to arrhythmias, e.g., digitalis, diuretics, or anti-arrhythmics. In such patients, epinephrine may precipitate or aggravate angina pectoris as well as produce ventricular arrhythmias. (b) The effects of epinephrine may be potentiated by tricyclic antidepressants and monoamine oxidase inhibitors. (c) Some patients may be at greater risk of developing adverse reactions after epinephrine administration. These include patients with hyperthyroidism, cardiovascular disease, hypertension, diabetes, and elderly individuals, and pregnant women. It must be noted that, despite these concerns, epinephrine is essential for the treatment of anaphylaxis. Therefore, patients with these conditions, or any other person who might be in a position to administer epinephrine to a patient with these conditions experiencing anaphylaxis, should be instructed about the circumstances under which epinephrine should be used.. Twinject 0.3 mg (Epinephrine) Price Comparisons - Discounts, Cost & Coupons Before you buy Twinject 0.3 mg (Epinephrine), find the lowest cost Twinject prices at local U.S. pharmacies by using the drug discount coupon search at the bottom of this page..