TWINJECT- epinephrine injection
Shionogi Pharma, Inc.

Available as: 0.3 mg 0.15 mg

each dose delivers 0.15 mg or 0.3 mg of epinephrine



Twinject auto-injector contains 1.1 mL epinephrine injection, USP 1:1000 (1 mg/mL), from which two doses of either 0.15 mg (0.15 mL) or 0.3 mg (0.3 mL) each are available for use by injection. The first dose is administered by auto-injection after the patient prepares and fires Twinject as directed. A second dose can be manually administered following a partial disassembly of Twinject. The remaining volume is not available for use and should be discarded. See PATIENT DIRECTIONS FOR USE on the accompanying Patient Information Leaflet.

Each dose of epinephrine injection, USP 1:1000 contains either 0.15 mg or 0.3 mg l-epinephrine, sodium chloride, chlorobutanol and sodium bisulfite, all sealed under nitrogen.

Epinephrine is a sympathomimetic catecholamine. Its naturally occurring l-isomer, which is twenty times as active as the d-isomer, is obtained in pure form by separation from the synthetically produced racemate.

Chemically, epinephrine is 1-(3,4-dihydroxyphenyl)-2-(methylamino)ethanol with the following structure:

Chemical Structure

Epinephrine deteriorates rapidly on exposure to air or light, turning pink from oxidation to adrenochrome and brown from the formation of melanin. Epinephrine solutions that show evidence of discoloration should be discarded.

Twinject contains no latex.


Epinephrine is the drug of choice for the emergency treatment of severe allergic reactions (Type I) to allergens, such as those present in certain insect venoms, foods, or drugs. It can also be used in the treatment of anaphylaxis of unknown cause (idiopathic anaphylaxis) or exercise-induced anaphylaxis. Epinephrine, when given intramuscularly or subcutaneously, has a rapid onset and short duration of action. Epinephrine acts on both alpha and beta adrenergic receptors. Through its action on alpha adrenergic receptors, epinephrine lessens the vasodilation and increased vascular permeability that occurs during an anaphylactic reaction and can lead to loss of intravascular fluid volume and hypotension. Through its action on beta adrenergic receptors, epinephrine causes bronchial smooth muscle relaxation that helps alleviate bronchospasm, wheezing, and dyspnea that may occur during anaphylaxis. Epinephrine also helps alleviate pruritus, urticaria, and angioedema, and may be effective in relieving gastrointestinal and genitourinary symptoms of anaphylaxis because of its relaxer effects on the smooth muscle of the stomach, intestine, uterus and urinary bladder.


Twinject (epinephrine injection, USP 1:1000) is indicated in the emergency treatment of severe allergic reactions (Type I) including anaphylaxis to stinging insects (e.g. order Hymenoptera, which includes bees, wasps, hornets, yellow jackets and fire ants), and biting insects (e.g. triatoma, mosquitos), allergen immunotherapy, foods, drugs, diagnostic testing substances (e.g. radiocontrast media), and other allergens, as well as anaphylaxis to unknown substances (idiopathic anaphylaxis) or exercise-induced anaphylaxis. Twinject is intended for immediate administration in patients with a history of anaphylactic reactions. Selection of the appropriate dosage strength is determined according to patient body weight (See DOSAGE AND ADMINISTRATION section).

Such reactions may occur within minutes after exposure and consist of flushing, apprehension, syncope, tachycardia, thready or unobtainable pulse associated with a fall in blood pressure, convulsions, vomiting, diarrhea and abdominal cramps, involuntary voiding, wheezing, dyspnea due to laryngeal spasm, pruritus, rashes, urticaria, or angioedema. Twinject is designed as emergency supportive therapy only and is not a replacement or substitute for immediate medical care.


There are no absolute contraindications to the use of epinephrine in a life-threatening allergic reaction.


Twinject should only be injected into the anterolateral aspect of the thigh. Accidental injection into the hands or feet may result in loss of blood flow to the affected area and should be avoided. DO NOT INJECT INTO BUTTOCK. If there is an accidental injection into these areas, advise the patient to inform the healthcare provider of the accidental injection when he/she goes to the nearest emergency room for further treatment of anaphylaxis.

Avoid possible inadvertent intravascular administration. Large doses or accidental intravenous injection of epinephrine may result in cerebral hemorrhage due to a sharp rise in blood pressure. DO NOT INJECT INTRAVENOUSLY. Rapidly acting vasodilators can counteract the marked pressor effects of epinephrine if there is such inadvertent administration.

Epinephrine is the preferred treatment for serious allergic reactions or other emergency situations even though this product contains sodium bisulfite, a sulfite that may, in other products, cause allergic-type reactions including anaphylactic symptoms or life-threatening or less severe asthmatic episodes in certain susceptible persons. The alternatives to using epinephrine in a life-threatening situation may not be satisfactory. The presence of a sulfite in this product should not deter administration of the drug for treatment of serious allergic or other emergency situations, even if the patient is sulfite-sensitive.

Epinephrine should be administered with caution to patients with cardiac arrhythmias, coronary artery or organic heart disease, or hypertension. In patients with coronary insufficiency or ischemic heart disease, epinephrine may precipitate or aggravate angina pectoris as well as produce ventricular arrhythmias. It should be recognized that the presence of these conditions is not a contraindication to epinephrine administration in an acute, life-threatening situation.

Epinephrine is light sensitive and should be stored in the carrying-case provided. Store at room temperature (20°-25°C/68°-77°F) with excursions permitted to 15°-30°C (59°-86°F). Do not refrigerate; protect from freezing. Patients should periodically check the solution in Twinject for any discoloration and/or precipitates. If the solution is discolored or contains a precipitate, the patient should replace their Twinject.


(1) General

Twinject is not intended as a substitute for immediate medical care. In conjunction with the administration of epinephrine, the patient should seek appropriate medical care. More than two sequential doses of epinephrine should only be administered under direct medical supervision.

Twinject is not suitable for patients, or caregivers, with such disabilities as severe debilitating arthritis of the hands, because the use of this product requires some manual dexterity to administer. IN ALL CASES, THE PHYSICIAN SHOULD INSTRUCT THE PATIENT AND/OR ANY OTHER PERSON WHO MIGHT BE IN A POSITION TO ADMINISTER THE EPINEPHRINE, IN THE PROPER USE OF Twinject.

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 INDICATIONS AND USAGE 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.

(2) Information for Patients

Complete patient information, including dosage, directions for proper administration, and precautions, can be found inside each Twinject package within the Patient Information Leaflet.

Epinephrine may produce symptoms and signs that include an increase in pulse rate, the sensation of a more forceful heartbeat, palpitations, a throbbing headache, pallor, feelings of overstimulation, anxiety, weakness, shakiness, dizziness, or nausea. These signs and symptoms usually subside rapidly, especially with rest, quiet, and recumbency.

Patients with hypertension or hyperthyroidism may develop more severe or persistent effects, and patients with coronary artery disease could experience angina. Patients with diabetes may develop increased blood glucose levels following epinephrine administration. Patients with Parkinson’s disease may notice a temporary worsening of symptoms.

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