Adrenergic and Antiadrenergic Drugs PDF

# Adrenergic and Antiadrenergic Drugs ## Adrenergic Drugs - Adrenergic drugs mimic or enhance the effects of the sympathetic nervous system, specifically the actions of the neurotransmitters epinephrine and norepinephrine. - These drugs act on adrenergic receptors throughout the body leading to ph...

# Adrenergic and Antiadrenergic Drugs ## Adrenergic Drugs - Adrenergic drugs mimic or enhance the effects of the sympathetic nervous system, specifically the actions of the neurotransmitters epinephrine and norepinephrine. - These drugs act on adrenergic receptors throughout the body leading to physiological responses such as: - Increased heart rate - Elevated blood pressure - Bronchodilation - Heightened alertness ## Distribution of Adrenergic Receptors | Receptor | Location | |---|---| | α1 | Arterioles (coronary, visceral, cutaneous), veins, internal sphincters, iris dilator muscle | | α2 | Presynaptic membrane, pancreas, veins, adipose tissue, GIT sphincters, salivary glands | | β1 | Heart (SA node, atrial muscle, AV node, ventricles), kidney (juxtaglomerular apparatus), adipose tissue | | β2 | Arterioles (muscular), veins, bronchi (muscles), liver, pancreas, uterus, iris constrictor muscle | | β3 | Adipose tissue, urinary bladder | ## Uses of Adrenergic Drugs in Surgery - **Hemostasis**: Adrenergic drugs like epinephrine and norepinephrine are used to induce vasoconstriction and control bleeding during surgical procedures. - **Hypotension treatment**: These drugs can be used to raise blood pressure in cases of hypotension during surgery. Phenylephrine and dopamine are examples used to increase blood pressure and maintain adequate perfusion. - **Bronchodilation**: Adrenergic bronchodilators such as albuterol and salmeterol are used to open up the airways, facilitating breathing during surgeries, especially those involving the respiratory system. - **Local anesthesia prolongation**: Addition of adrenergic agonists like epinephrine to local anesthetics can prolong the duration of anesthesia by constricting blood vessels and slowing the absorption of the anesthetic agent. ## Side Effects of Adrenergic Drugs - Increased heart rate - Hypertension - Arrhythmias ## Antiadrenergic Drugs - Antiadrenergic drugs inhibit the actions of the sympathetic nervous systems and its neurotransmitters, such as epinephrine and norepinephrine. - These drugs act on adrenergic receptors leading to physiological effects such as: - Decreased heart rate - Lowered blood pressure - Reduced contractility of the heart ## Uses of Antiadrenergic Drugs in Surgery - **Blood pressure control**: Antiadrenergic drugs like beta-blockers such as propranolol and metoprolol are used to manage and control high blood pressure during and after surgery. - **Arrhythmia management**: They are used to control and prevent irregular heart rhythms during surgical procedures. Examples include atenolol and esmolol which are used to manage tachyarrhythmias. - **Anxiety and stress reduction**: These drugs can help manage preoperative anxiety and stress, thereby promoting a smoother surgical experience for the patient. Medication like propranolol can be used for this purpose. - **Migraine prevention**: Some antiadrenergic drugs, such as propranolol and timolol, are used to prevent migraines which can be triggered by certain stimuli encountered during surgery. ## Side Effects of Antiadrenergic Drugs - Bradycardia - Hypotension - Fatigue