Chapter 24- Adrenergic Drugs
Sympathomimetic:
Drugs that mimic the actions of the sympathetic nervous system; see adrenergic.
PP Slide #7: Adrenergic Drugs: Actions
alpha (α) receptors: •Alpha 1 - Constricts Peripheral Blood vessels •Alpha 2 - slows GI tract motility & secretions beta (β) receptors: • Beta 1 - Increases Heart rate & contractility • Beta 2 - Bronchodilation (relaxes lung smooth muscle); Constricts Peripheral Blood vessels.
PP Slide #13: Adrenergic Drugs to Know
dopamine - for shock due to trauma, MI, decompensated CHF, renal failure. epinephrine - for anaphylaxis, cardiac arrest isoproterenol - for shock, bronchospasm, cardiac standstill and arrhythmias.
PP Slide #17: Nursing Process: Implementation
- Administer norepinephrine, dopamine only via IV route. - Do not mix dopamine with other drugs. - Monitor blood pressure continuously. - Adjust rate: titration to maintain B/P as ordered.
Discuss the activity of the autonomic nervous system, specifically the sympathetic branch.
- Autonomic nervous system is a system of nerves that automatically regulates bodily functions.ANS is divided into sympathetic and the parasympathetic. Sympathetic is branch is regulated by involuntary control (*often called the fight or flight response*). Nerves are activated whine the body is confronted with stressful situations. Controls heart rate, breathing rate and ability to divert blood to the skeletal muscles. Norepinephrine is a neurotransmitter produced naturally by the body = primary neurotransmitter in the sympathetic branch of the ANS and the substance that keeps the nerve message or impulse going from the brain to the target organ. This system is activated by the precursor of epinephrine (adrenalin) another term for the sympathetic pathway is the adrenergic branch. That's why meds used that work like the adrenergic branch are called adrenergic drugs. - In the sympathetic branch of the autonomic nervous system, adrenergic drugs produce activity similar to the neurotransmitter norepinephrine. Another name for these drugs is sympathomimetic (i.e., mimicking the actions of the sympathetic nervous system) drugs. The adrenergic drugs produce pharmacologic effects similar to the effects that occur in the body when the sympathetic nerves (norepinephrine) and the medulla (epinephrine) are stimulated. The primary effects of these drugs occur on the heart, the blood vessels, and the smooth muscles, such as the bronchi of the lung.
PP Slide #8: Adrenergic Drugs: Actions
- Isoproterenol (Isuprel) is selective & acts only on beta receptors Useful for shock & bronchospasm
PP Slide #16: Nursing Process: Implementation
- Management of shock is aimed at providing basic life support; drugs used: vasopressors, antibiotics, inotropes, hormones. - Report & document patient c/o on adrenergic drugs; report adverse effects immediately - especially cardiac arrhythmias - continuous cardiac monitoring.
PP Slide #15: Nursing Process: Diagnoses
- Nursing Diagnoses: for Shock Ineffective Tissue Perfusion related to hypovolemia, blood loss, impaired distribution of fluid, impaired circulation, impaired transport of oxygen across alveolar and capillary bed Decreased Cardiac Output related to altered heart rate and/or rhythm Disturbed Sleep Pattern related to adverse reactions (nervousness) to the drug and the environment.
PP Slide #23: Nursing Process: Diagnosis
- Risk for Allergy: Response related to response to substance trigger (insect sting, drug allergy, specific food).
PP Slide #10: Adrenergic Drugs: Uses
- Shock: state of inadequate tissue perfusion o Symptoms: (Pg. 265, T. 24.4), Pale, cold, clammy skin, confusion, tachycardia, hypotension, tachypnea, decreased urine output.
Discuss important preadministration and ongoing assessment activities the nurse should perform on the patient taking an adrenergic drug.
- When a patient is to receive an adrenergic agent for shock, obtain the blood pressure, pulse rate and quality, and respiratory rate and rhythm. Assess the patient's symptoms, problems, or needs before administering the drug, and document any subjective or objective data on the patient's record. In emergencies, assessments are made quickly and accurately. This information provides an important database that is used during treatment. A general survey of the patient also is necessary. It is important to look for additional symptoms of shock, such as cool skin, cyanosis, diaphoresis, and a change in the level of consciousness. Other assessments may be necessary if the hypotensive episode is due to trauma, severe infection, or blood loss. - During the ongoing assessment, observe the patient for the effect of the drug, such as improved breathing of the patient with asthma, or response of blood pressure to the administration of the vasopressor. During therapy, evaluate and document the drug effect and vital signs. Comparison of assessments made before and after administration may help the primary health care provider determine future use of the drug for this patient. It is important to report adverse drug reactions to the primary health care provider as soon as possible. When a patient has self-administered a drug for a life-threatening allergic reaction, try to get as much information as possible from the patient about the incident leading up to using the drug. If the patient was with family or friends, gain subjective data from these people regarding the events leading up to the need for drug injection.
Key Point #5:
Adverse reactions include increased blood pressure, nausea, vomiting, headache, and cardiac arrhythmias.
Peripheral Nervous System (PNS):
All nerves outside of brain and spinal cord.
Neurotransmitter:
Chemical substances released at the nerve ending that facilitate the transmission of nerve impulses.
PP Slide #29: Adrenergic Drugs: Contraindications
Contraindicated in patients: o Epinephrine: narrow-angle glaucoma, local anesthetic adjunct in fingers, toes o Isoproterenol: tachyarrhythmias, heart block caused by digitalis toxicity, ventricular arrhythmias, angina pectoris.
PP Slide #20: Nursing Process: Diagnosis
Decreased cardiac output: Shock Heart rate, stroke volume determine cardiac output Stroke volume: contractile state of heart, amount of blood in ventricle available to be pumped out Cardiogenic Shock: monitor vital signs; determine severity of shock. Progressive fall in blood pressure: serious, immediately report to HCP.
PP Slide #21: Nursing Process: Diagnosis
Disturbed sleep pattern: Overstimulation in ICU Critical care setting: daily pattern of activities is usually disrupted: alarms, several HCP, testing causes overstimulation Patients can easily get confused regarding daytime Causes great deal of stress in patient & unable to sleep Identify circumstances: nurse taking vital signs during night or turning overhead light on during night Weigh importance of monitoring status, vital signs, providing comfort interventions. Explain reason for close monitoring of vital signs
Autonomic Nervous System (ANS):
Division of the peripheral nervous system concerned with functions essential to the life of the organism and not consciously controlled (e.g., blood pressure, heart rate, gastrointestinal activity).
List nursing diagnoses particular to a patient taking an adrenergic drug.
Drug-specific nursing diagnoses are the following: - Risk for Allergy Response related to response to substance trigger (insect sting, drug allergy, specific food). - Ineffective Tissue Perfusion related to hypovolemia, blood loss, impaired distribution of fluid, impaired circulation, impaired transport of oxygen across alveolar and capillary bed, other (specify). - Decreased Cardiac Output related to altered heart rate and/or rhythm. - Disturbed Sleep Pattern related to adverse reactions (nervousness) to the drug and the environment.
Key Point #3:
Drugs that mimic the sympathetic response are called sympathomimetic or adrenergic (because the primary transmitter is adrenalin or epinephrine). Actions in the body are modified depending on how the drug acts on different cell receptors. Drugs can be selective for alpha or beta receptors. Drugs can also be nonselective.
Vasopressors:
Drugs that raise the blood pressure.
Extravasation:
Escape of fluid from a blood vessel into surrounding tissue.
Shock:
Inadequate blood flow to the bodily tissues.
Discuss the types of shock, physiologic responses of shock, and the use of adrenergic drugs in the treatment of shock.
Management of shock is aimed at providing basic life support (airway, breathing, and circulation) while attempting to correct the underlying cause. Types Of Shocks: - Hypovolemic; Occurs when the blood volume is significantly diminished. - Cardiogenic-obstructive shock; Occurs when cardiac output is insufficient and perfusion to the vital organs cannot be maintained. Obstructive shock is categorized with cardiogenic shock. It occurs when obstruction of blood flow results in inadequate tissue perfusion. - Distributive (vasogenic) shock- Occurs when there are changes to the blood vessels causing dilation, but no additional blood volume. The blood is redistributed within the body. This category is further differentiated; -Septic Shock: Circulatory insufficiency resulting from overwhelming infection - Anaphylactic Shock: hypersensitivity resulting in massive systemic vasodilation. - Neurogenic Shock: Interference with PNS control of blood vessels.
Discuss ways to promote an optimal response to therapy, how to manage common adverse reactions, and important points to keep in mind when educating patients about the use of adrenergic drugs.
Management of the patient receiving an adrenergic agent varies and depends on the drug used, the reason for administration, and the patient's response to the drug. In most instances, adrenergic drugs are potent and potentially dangerous. Minimize distractions and exercise great care in the calculation and preparation of these drugs for administration. Although adrenergic drugs are potentially dangerous, proper supervision and management before, during, and after administration will minimize the occurrence of any serious problems. Report and document any complaint the patient may have while taking an adrenergic drug. However, nursing judgment is necessary when reporting adverse reactions. Report adverse effects, such as the development of cardiac arrhythmias, immediately, regardless of the time of day or night. Yet, other adverse effects, such as a nervous feeling, need not be dealt with on an emergent basis. Once a patient has experienced an allergic reaction, he or she is at risk for having another reaction. Triggers can include foods, stinging insects, latex, chemical or environmental items, and even exercise.
PP Slide #28: Adrenergic Drug Adverse Reactions
Most serious Adrenergic Drug Adverse Reactions includes Cardiac Arrhythmias & Hypertension.
Norepinephrine:
Neurotransmitter that transmits impulses across the sympathetic branch of the autonomic nervous system.
Aatecholamine:
Neurotransmitters that are released during the body's stress response and include norepinephrine, epinephrine, and dopamine.
PP Slide #5: Fight or Flight Responses to Stressors
Norepinephrine is the primary neurotransmitter.
Parasympathetic:
Pertaining to the part of the autonomic nervous system concerned with conserving body energy (i.e., slowing the heart rate, digesting food, and eliminating waste).
Adrenergic:
Pertaining to the sympathetic branch of the nervous system, which controls heart rate, breathing rate, and ability to divert blood to the skeletal muscles.
Sympathetic:
Pertaining to the sympathetic nervous system.
NURSING ALERT #2:
Regardless of the actual numeric reading of the blood pressure, a progressive decrease in blood pressure is serious. Report any progressive decrease in blood pressure, a decrease in systolic blood pressure below 100 mm Hg, or any decrease of 20 mm Hg or more of the patient's normal blood pressure.
NURSING ALERT #1:
Supine hypertension is a potentially dangerous adverse reaction in the patient taking midodrine. The drug should be given only to patients whose lives are impaired despite standard treatment offered. This reaction is minimized by administering midodrine during the day while the patient is in an upright position. The suggested dosing schedule for the administration of midodrine is shortly before arising in the morning, midday, and late afternoon (not after 6:00 PM). Drug therapy should continue only in the patient whose orthostatic hypotension improves during the initial treatment.
Discuss the uses, general drug actions, contraindications, precautions, interactions, and adverse reactions associated with the administration of adrenergic vasopressor drugs.
The purpose of stimulating the sympathetic (adrenergic) nerves is to divert blood flow to the vital organs so that the body can deal with a stressful situation (the fight-or-flight response). In general, adrenergic drugs produce one or more of the following responses in varying degrees: • Central nervous system—wakefulness, quick reaction to stimuli, quickened reflexes • Autonomic nervous system—relaxation of the smooth muscles of the bronchi, constriction of blood vessels, sphincters of the stomach, dilation of coronary blood vessels, decrease in gastric motility • Heart—increase in the heart rate • Metabolism—increased use of glucose (sugar) and liberation of fatty acids from adipose tissue. Neurotransmitter (e.g., norepinephrine), is released by the presynaptic nerve, crosses the synapse, and binds with α and β receptors in the cell membrane of the postsynaptic nerve, continuing the transmission of the nerve impulse. Whether an adrenergic drug acts on α, β, or α and β receptors accounts for the variation of responses to this group of drugs. Table 24.1 lists the type of adrenergic nerve receptor that corresponds with each action of the autonomic nervous system on the body. The α and β receptors can be further grouped as α1- and α2-adrenergic receptors and β1- and β2-adrenergic receptors.
Key Point #1:
The sympathetic branch of the autonomic nervous system regulates involuntary body functions. The primary neurotransmitter of the sympathetic branch is norepinephrine; activation of this system is often called the fight, flight, or freeze response.
Stroke Volume:
The volume of blood ejected (leaving) from a ventricle at each heart beat.
Key Point #4:
These drugs are used to treat shock, hypotension, allergic reactions, heart conditions, and bronchoconstriction. Topical formulas are used for glaucoma and nasal congestion. Older individuals are very susceptible to adverse reactions, especially to epinephrine.
PP Slide #6: Adrenergic Drugs: Actions
To divert blood flow to vital organs to deal with stressful situation &/or save life: o CNS: Wakefulness; quick reaction to stimuli; quickened reflexes o Heart: Increase in heart rate & contractility o Autonomic nervous system: Relaxation of smooth muscles of bronchi; dilation of pupils; constriction of blood vessels; decrease gastric motility o Metabolism: Increase glucose from liver and adipose tissue
PP Slide #11: Adrenergic Drugs: Uses
Types of shock: - Distributive (vasogenic) - changes to blood vessels causing dilation - Septic - overwhelming infection.
Key Point #2:
When the sympathetic nerves are stimulated, the purpose is to divert blood flow to the vital organs so the body can deal with the stressful situation. A person becomes wakeful with quicker reflexes and pupils dilate. The smooth muscles of the bronchi relax as do the coronary vessels and the heart rate increases. Blood flow is constricted to areas such as the GI and genitourinary systems.