Epinephrine (EpiPen)

Product Information

• EpiPen®: Sterile epinephrine injection, 0.3 mg auto-injector.
• EpiPen Jr®: Sterile epinephrine injection, 0.15 mg auto-injector.
• Manufacturer: Mylan Specialty L.P.
• Indications: Emergency treatment of anaphylactic reactions in patients at increased risk, including those with a history of anaphylaxis.

Clinical Use

• Route of Administration: Intramuscular injection into the anterolateral aspect of the thigh.
• Indications: Treatment for severe allergic reactions (Type I), including reactions from foods, stinging and biting insects, medications, latex, idiopathic anaphylaxis, and exercise-induced anaphylaxis.

Mechanism of Action

• Epinephrine acts on alpha- and beta-adrenergic receptors, counteracting vasodilation and increasing vascular permeability, which can lead to hypotension during anaphylactic reactions. It also relaxes bronchial smooth muscles and alleviates pruritus, urticaria, and angioedema.

Dosage and Administration

• EpiPen® (0.3 mg): For adults and children weighing 30 kg or more.
• EpiPen Jr® (0.15 mg): For children weighing between 15 kg and 30 kg.
• Initial dose should be administered at the onset of symptoms, with additional doses as needed every 5-15 minutes.
• Patients should carry two auto-injectors at all times.

Warnings and Precautions

• Immediate Medical Care: EpiPen is for emergency use and does not replace medical or hospital care.
• Injection Site: Should only be injected into the thigh; avoid injection into the buttock, hands, feet, or digits.
• Education: Patients and caregivers should be thoroughly instructed on the use of EpiPen.
• Biphasic Reactions: Awareness of potential second-phase reactions that can occur hours after the initial treatment.

Adverse Reactions

• Common: Anxiety, tremor, weakness, dizziness, sweating, tachycardia, and palpitations.
• Serious: Cerebral hemorrhage, ventricular arrhythmias, gas gangrene (if injected into the buttock), and infections at the injection site.

Absolute Contraindications

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

Relative Contraindications

Epinephrine should be used with caution in the following conditions due to the potential for more severe or persistent adverse effects:

1. Cardiovascular Conditions:

• Cardiogenic, traumatic, or hemorrhagic shock
• Cardiac dilation
• Cerebral arteriosclerosis
• Cardiac arrhythmias
• Coronary artery or organic heart disease
• Hypertension
• Patients on medications that may sensitize the heart to arrhythmias (e.g., digitalis, diuretics, or anti-arrhythmics). Epinephrine may precipitate or aggravate angina pectoris as well as produce ventricular arrhythmias in these patients.

2. Endocrine and Metabolic Conditions:

• Diabetes: May cause increased blood glucose levels.
• Hyperthyroidism: Prone to more severe or persistent effects.
• Phaeochromocytoma
• Severe renal impairment
• Hypercalcaemia
• Hypokalaemia

3. Neurologic Conditions:

• Organic brain damage
• Parkinson’s disease: May notice a temporary worsening of symptoms after treatment.

4. Ophthalmologic Conditions:

• Narrow-angle glaucoma.

5. Respiratory Conditions:

• Concomitant asthma, especially if poorly controlled: Significantly increased risk of respiratory symptoms and increased risk of death from anaphylaxis.
• Pulmonary edema: May result from peripheral constriction and cardiac stimulation, potentially fatal.

6. Other Conditions:

• Elderly patients: Particularly at risk for epinephrine overdose and should be monitored carefully.
• Pregnant women: Although there are no adequate and well-controlled studies in pregnant women, epinephrine should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.

Sensitivity

• This product contains sodium metabisulfite, a substance which may cause allergic-type reactions including anaphylactic symptoms or mild to severe asthmatic episodes in certain susceptible persons. However, epinephrine is still the drug of choice for serious allergic reactions, and the presence of a sulfite in this product should not deter administration for serious allergic or other emergency situations, even if the patient is sulfite-sensitive.

Storage and Stability

• Store at 25°C (77°F); excursions permitted to 15° - 30°C (59° - 86°F).
• Do not refrigerate or freeze. Protect from light.
• Regularly check the solution for discoloration or particles and replace if necessary.

Overdosage

• Symptoms: Extremely elevated blood pressure, cerebral hemorrhage, bradycardia, tachycardia, arrhythmias, and pulmonary edema.
• Treatment: Supportive measures and administration of alpha-adrenergic blocking drugs or vasodilators as necessary.

Special Populations

• Geriatrics: Careful monitoring to avoid overdose.
• Pediatrics: Safety and effectiveness similar to adults.
• Pregnancy: Use only if benefits justify potential risks.

Consumer Information

• Usage: For emergency self-administration in case of anaphylaxis.
• Symptoms of Anaphylaxis: Hives, swelling, difficulty breathing, wheezing, and decreased blood pressure.
• Instructions: Remove from carrier tube, inject into thigh, seek immediate medical attention, and avoid injecting into veins or other body parts.