Action and Spectrum

Actions and Spectrum:

Mechanism of Action:

• Inhaled beta-2 adrenergic agonists, such as albuterol (salbutamol), are the mainstay of treatment for bronchospasm in conditions like asthma and chronic obstructive pulmonary disease (COPD). The mechanism of action of inhaled beta-2 adrenergic agonists involves the following steps:
• Binding to Beta-2 Adrenergic Receptors: When inhaled, beta-2 adrenergic agonists selectively bind to and activate the beta-2 adrenergic receptors located on the smooth muscle cells of the bronchioles in the lungs.
• Activation of Adenylate Cyclase: Stimulation of the beta-2 adrenergic receptors leads to activating the adenylate cyclase, which catalyzes the conversion of ATP to cyclic AMP (cAMP).
• Increased cAMP Levels: Elevated levels of cAMP within the smooth muscle cells activate protein kinase A (PKA). PKA phosphorylates various intracellular proteins involved in smooth muscle contraction, leading to the relaxation of the bronchial smooth muscle.
• Bronchodilation: The relaxation of the bronchial smooth muscle results in bronchodilation, widening the airways and improving airflow. This helps relieve bronchospasm symptoms, such as wheezing, shortness of breath, and coughing.
• Spectrum of Activity: Inhaled beta-2 adrenergic agonists have a broad spectrum of activity in the management of respiratory conditions, including:
• Asthma: Inhaled beta-2 adrenergic agonists are used as rescue medications to treat acute asthma exacerbations. They provide rapid relief of bronchospasm and help restore normal breathing. They are also used as maintenance therapy in the management of persistent asthma.
• Chronic Obstructive Pulmonary Disease (COPD): Inhaled beta-2 adrenergic agonists are commonly prescribed to relieve bronchospasm and improve lung function in individuals with COPD, including chronic bronchitis and emphysema.
• Exercise-Induced Bronchoconstriction: Inhaled beta-2 adrenergic agonists can be used prophylactically to prevent exercise-induced bronchoconstriction (EIB) in individuals who experience bronchospasm during or after physical exertion.

Drug Interaction

Adverse Reaction

Frequency not defined

Increased blood pressure

Tachycardia

Black Box Warning

Black box warning:

None

Contraindication / Caution

Contraindications/caution:

Contraindications:

• Hypersensitivity: Individuals with known hypersensitivity or allergy to epinephrine or other components of the inhaled product should not use it. Allergic reactions to epinephrine can range from mild to severe and potentially life-threatening.
• Severe Cardiac Disease: epinephrine can stimulate the heart and increase heart rate and blood pressure. Individuals with severe underlying cardiac conditions, such as coronary artery disease, arrhythmias, or severe heart failure, may be at increased risk of cardiovascular complications and should avoid inhaled epinephrine without proper medical guidance.
• Uncontrolled hypertension: epinephrine can cause an increase in blood pressure. Individuals with uncontrolled or severe hypertension (high blood pressure) may be at risk of further elevations in blood pressure. They should use inhaled epinephrine with caution or avoid it altogether.
• Hyperthyroidism: epinephrine can affect thyroid hormone levels and worsen symptoms in individuals with hyperthyroidism. Inhaled epinephrine should be used cautiously in such cases and under the supervision of a healthcare professional.
• Diabetes: epinephrine can increase blood glucose levels. Individuals with diabetes may need to monitor their blood sugar more closely when inhaling epinephrine.

Caution:

• Cardiovascular Conditions: Inhaled epinephrine should be used cautiously in individuals with underlying cardiovascular conditions, such as hypertension, ischemic heart disease, arrhythmias, or heart failure. epinephrine can stimulate the heart and increase heart rate and blood pressure, which may worsen these conditions.
• Diabetes: epinephrine can increase blood glucose levels. Individuals with diabetes may need to monitor their blood sugar more closely when inhaling epinephrine. Adjustments in diabetes management, such as insulin dosage, may be necessary under the guidance of a healthcare professional.
• Hyperthyroidism: Inhaled epinephrine may affect thyroid hormone levels and worsen symptoms in individuals with hyperthyroidism. Use should be cautiously approached and supervised by a healthcare professional.
• Seizure Disorders: epinephrine can potentially lower the seizure threshold. Individuals with a history of seizure disorders or at risk of seizures should use inhaled epinephrine cautiously, and the benefits and risks should be carefully evaluated.
• Glaucoma: epinephrine can increase intraocular pressure. Individuals with glaucoma or a history of increased intraocular pressure should use inhaled epinephrine with caution and under the supervision of an eye care professional.
• Pregnancy and Breastfeeding: Using inhaled epinephrine during pregnancy or breastfeeding should be discussed with a healthcare professional. The potential risks and benefits must be evaluated, and alternative treatment options may be considered.

Pregnancy / Lactation

Pregnancy consideration: Poorly or moderately controlled asthma during pregnancy can lead to various complications, including an increased risk of preeclampsia in the mother.

Lactation: Excretion of the drug in human breast milk is unknown

Pregnancy category:

Category A: well-controlled and Satisfactory studies show no risk to the fetus in the first or later trimester.

Category B: there was no evidence of risk to the fetus in animal studies, and there were not enough studies on pregnant women.

Category C: there was evidence of risk of adverse effects in animal reproduction studies, and no adequate evidence in human studies must take care of potential risks in pregnant women.

Category D: adequate data with sufficient evidence of human fetal risk from various platforms, but despite the potential risk, and used only in emergency cases for potential benefits.

Category X: Drugs listed in this category outweigh the risks over benefits. Hence these categories of drugs need to be avoided by pregnant women.

Category N: There is no data available for the drug under this category

Pharmacology

Pharmacology:

Inhaled beta-2 adrenergic agonists, such as albuterol (salbutamol), are the mainstay of treatment for bronchospasm in conditions like asthma and chronic obstructive pulmonary disease (COPD). While epinephrine is not commonly used via inhalation, the pharmacology of inhaled beta-2 adrenergic agonists shares some similarities.

Pharmacodynamics:

• Adrenergic Agonist: epinephrine acts as a non-selective adrenergic agonist, stimulating alpha-adrenergic and beta-adrenergic receptors.
• Bronchodilation: epinephrine activates beta-2 adrenergic receptors in the smooth muscles of the bronchioles, resulting in their relaxation and subsequent bronchodilation. This effect helps to alleviate bronchospasm and improve airflow in conditions such as asthma or acute bronchospasm.
• Vasoconstriction: epinephrine stimulates alpha-adrenergic receptors in blood vessels, leading to vasoconstriction. This results in increased blood pressure and decreased vascular permeability. The vasoconstrictive effects of epinephrine contribute to its ability to control bleeding and maintain blood pressure during anaphylaxis or cardiac arrest.
• Increased Heart Rate and Contractility: epinephrine activates beta-1 adrenergic receptors in the heart, leading to increased heart rate (positive chronotropic effect) and increased force of contraction (positive inotropic effect). This helps to improve cardiac output and restore circulation in situations such as cardiac arrest.
• Glycogenolysis: epinephrine stimulates glycogenolysis, the breakdown of glycogen into glucose, in liver and muscle tissues. This increases blood glucose levels, providing energy during stressful situations or hypoglycemia.

Pharmacokinetics:

Absorption

When inhaled, epinephrine is absorbed into the bloodstream through the respiratory tract mucosa. Inhaled medications are designed to be rapidly absorbed and reach therapeutic concentrations quickly.

Distribution

Once in the bloodstream, epinephrine is distributed throughout the body. It can act on various target tissues and organs, including the lungs, heart, and blood vessels.

Metabolism

epinephrine is primarily metabolized by enzymes such as catechol-O-methyltransferase (COMT) and monoamine oxidase (MAO). These enzymes break down epinephrine into inactive metabolites, such as metanephrine and vanillylmandelic acid (VMA). The metabolism of epinephrine occurs mainly in the liver and other tissues.

Elimination and Excretion

The metabolites of epinephrine are eliminated from the body through urine. They can be measured in urine samples as part of diagnostic tests for certain conditions, such as pheochromocytoma (a tumor that affects adrenal gland function).

Adminstartion

Administration:

• Properly prepare the inhaler device: Make sure the inhaler device is assembled and ready for use. Follow the instructions provided by the manufacturer or healthcare professional.
• Prime the inhaler: If it is new or has not been used in a while, it may need to be primed before use. Priming involves releasing a small medication spray to ensure the inhaler works appropriately. Follow the instructions provided by the manufacturer or healthcare professional for proper priming.
• Breathe out completely: Take a deep breath and exhale to empty your lungs.
• Place the inhaler in your mouth: Hold it upright and place the mouthpiece, sealing your lips around it.
• Inhale deeply: Press down on the inhaler to release the medication and inhale deeply. Hold your breath for a few seconds, then exhale slowly.
• Repeat as directed: In some cases, multiple inhalations may be necessary to achieve the desired therapeutic effect. Follow the specific instructions provided by the healthcare professional.
• Clean the inhaler: After use, clean the inhaler according to the instructions provided by the manufacturer or healthcare professional.

Patient Information Leaflet

Patient information leaflet

Generic Name: epinephrine inhaled

Why do we use epinephrine inhaled?

Inhaled epinephrine may also treat other respiratory conditions, such as chronic obstructive pulmonary disease (COPD) or acute bronchitis. In rare instances, inhaled epinephrine may be considered for treating acute bronchospasm or asthma. Still, it is not typically the first-line treatment choice. Inhaled beta-2 adrenergic agonists, such as albuterol (salbutamol), are more commonly used.

Albuterol inhalers are preferred due to their more selective action on beta-2 adrenergic receptors and their established efficacy and safety profiles in treating bronchospasm and asthma. Albuterol inhalers provide targeted bronchodilation and are considered the standard of care for relieving acute symptoms.