NR 508 Chapter 17: Drugs Affecting the Respiratory System – Download For An A+

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NR 508 Chapter 17: Drugs Affecting the Respiratory System – Download For An A+ Bronchodilators Beta 2- Receptor Agonists • Used to treat reversible bronchoconstriction for all ages of pat... ients for asthma, COPD and reactive airway disease. • Variety of delivery systems: inhaled, oral, subcutaneous, etc. Pharmacodynamics • Works on the smooth muscle of the bronchial tree which reverses bronchospasm and ultimately increases vital capacity and airflow. • Unfortunately, like a lot of other medications, there’s effects on other body systems o CNS = anxiety, irritability, dizziness, tremors o Cardiac = tachycardia and vascular smooth muscles would be dilated which would cause a decrease in diastolic blood pressure and reflux tachycardia o Skeletal = tremors Pharmacotherapeutics • Due to its effects on the heart, it is contraindicated in those with coronary insufficiency, ischemic heart disease, hypertension, CHF, arrhythmias, etc. • For those with diabetes, there could be a potential for drug induced hyperglycemia, so caution is advised • There is a black box warning about long acting beta agonists and their use in asthma due to the increased risk of intubation and death o Long acting beta agonists should never be used alone for asthma but can be used in a combination product like with an inhalation corticosteroid o Must use the lowest dose possible for the shortest amount of time possible. Clinical Use • Can be used for exercise induced asthma, giving 1-2 puffs 15-30 minutes prior to exercise • Can be used for bronchospasms, asthma, acute or chronic bronchitis & COPD. • There are different medications that have different indications based on age o Albuterol can be used at any age including infants versus levalbuterol should not be used for kids ages less than 4 years • Albuterol is the least expensive Monitoring • Have patients use peak flow meters is really important because it helps the patient and the provider determine if the patient is having good efficacy of use of the medications prescribed and can tell you quantitatively how much the patient is improving by Patient Education • Must demonstrate how to use an inhaler and never assume that a patient knows how to use one even if they have been using one for years • Have the patient demonstrate it back to the provider • Patients should be instructed for the potential of ADRs and if overused chronically, they can potentially have anginal pain, hypertension, hypokalemia and even seizures. • Patients should avoid any known triggers and to help determine that, patients can keep a journal o If a patient were to have an asthmatic exacerbation, they would journal what they were exposed to or ate in the last 24 hours • Stop smoking and avoid second hand smoke Xanthine Derivatives • Aminophylline, caffeine and theophylline Pharmacodynamics • Mostly unknown • There is selective inhibition of specific phosphodiesterases which increases cyclic AMP which then This study soluercaedwsastodorwenlloaaxdeadtiboy n10o00f00b8r8o30n5c54h0i6aflrosmmCoouortsheHmerou.csocmloena0n7-d04-p2u02l4m00o:n37a:0r7yGvMeTs-s0e5l:0s0 • Caffeine and theophylline act on the CNS through stimulation which often causes insomnia and excitability o They affect the cardiovascular system and increase cardiac contractility and heart rate o They affect the skeletal muscles and can cause tremors o Can cause diuresis or increasing renal blood flow and GFR Pharmacokinetics • Theophylline is a third line medication due to its narrow therapeutic window and multiple things that can affect its metabolism and potential for severe ADRs o Theophylline’s absorption can be greatly affected by food and gastric pH, so it is important to educate patients about the timing of taking the medication and ingestion of food o Theophylline requires close monitoring of serum levels since it has a narrow therapeutic window o There is extensive metabolism by the liver ▪ There are different half-lives based on the age of the patient o Smoking increases theophylline excretion o A high carbohydrate diet can decrease its excretion o True contraindications to theophylline are besides sensitivity to xanthines: peptic ulcer disease and underlying seizure disorder ADRS • For theophylline (and similarly caffeine) o CNS = irritability, restlessness, seizures and insomnia o Cardiac = arrhythmias, even life threatening and hypotension o GI= reflex Clinical Use • Asthma and COPD • However, it is 3rd line due to narrow therapeutic index window and ADRs • Also indicated for apnea of prematurity Rational Drug Selection • Consider immediate versus timed verses liquid formulations Monitoring • Very important for those on theophylline due to potential for toxicity, headaches, jitteriness, convulsions, irregular heart rate, nausea, vomiting, severe abdominal pain, rash, etc. Patient Education • Consistency of taking medications is very important otherwise there may be a sub therapeutic dose or toxicity dose • Have a consistent diet with administration of drugs • A diet low in carbs and high in protein increases elimination of theophylline and vice versa • Avoid large amounts of caffeine for patients on theophylline to avoid ADRs • Self-monitoring respiratory status with peak flow meter • Quit smoking • Avoid triggers for asthma Anticholinergics • Inhaled anticholinergics are used primarily for COPD but when combined with albuterol, can be used for the emergent treatment of asthma exacerbation Pharmacodynamics • All act about the same • Block the muscarinic cholinergic receptors decreasing cyclic GMP on intracellular calcium Pharmacokinetics • 1-2% is systemically absorbed Pharmacotherapeutics • Inhaled anticholinergics should not be used for the treatment of acute bronchospasm except if it is combined with albuterol which would be Combivent • Caution for those who have BPH due to urinary retention and caution for those with closed angle glaucoma as it can increase intraocular pressure ADRS • Most common is cough, hoarseness, throat irritation, dygeusia (inability to taste) Clinical Use • COPD and asthma • COPD second line to those who are already on a bronchodilator and continue to have bronchospasms • Asthma (not exercise induced asthma) • Combination of ipratropium with albuterol, Combivent, second line, quick relief in treatment of asthma and note it is not tiotropium (long acting form of ipratropium) Patient Education • Demonstrate how to use inhalers, particularly metered dose inhalers and always consider a spacer • Lifestyle management of self-monitoring with a peak flow meter, avoid smoking, avoid asthma triggers and avoid viral infections Leukotriene Modifiers • Leukotrienes induce numerous effects such as inflammation, smooth muscle contractility, neutrophil aggregation, degranulation and chemotaxis • 5-lipoxygenase catalyzes the formation of leukotrienes Leukotriene Receptors Agonists Pharmacodynamics • Montelukast, zafirlukast • 5-lipooxygenase pathway inhibitor would be zileuton Pharmacotherapeutics • Not used for primary treatment of acute asthma attack • Be aware for chewable montelukast pills because they contain phenylalanine which is contraindicated in patients with PKU • Caution with severe hepatic dysfunction • Be careful administering leukotriene agonists in patients on concurrent systemic steroids o You can have a decrease in the steroids and the complications for which the steroids were ordered can come out • Potential for neuropsychiatric events with on leukotriene agonists ADRS • Fever, headache, myalgias, GI upset • Increase in upper respiratory infections in those 55 years and older taking zafirlukast Clinical Use • Asthma Monitoring • Asthmatic symptoms • How often a bronchodilator is used • Pulmonary function tests • Neuropsychiatric symptoms • Lifestyle modifications Respiratory Inhalants Corticosteroids • Very potent and effective anti-inflammatory class of medication • Different formations are different, and adjustments will likely have to be made when switching between them • Oral steroids are anti-inflammatory • Inhaled steroids inhibit IgE and mast cell mediated migration of inflammatory cells into the bronchial tissues Pharmacotherapeutics • Not used for an acute asthma attack • Caution and switch from oral to inhaled steroids because death is possible due to adrenal insufficiency ADRS • Xerostomia (dry mouth), tongue and mouth irritation, dysguesia (altered taste), hoarseness • Anyone on inhaled corticosteroids have the potential for oral candidacies o Provider should be teaching patients to rinse and spit after every use Clinical Use • Asthma • Nasal corticosteroids can be used for allergic rhinitis Rational Drug Selection • No guideline – providers choice Monitoring • ADRs and effectiveness • If on the medications for a prolonged period of time, they should be monitored for blood glucose and potassium Patient Education • If patient is using inhaled bronchodilators, the patient should wait a minute before subsequent administrations • Lifestyle modifications Inhaled Anti-Inflammatory Agents • Two examples: cromolyn sodium and nedocromil • Inhibit antigen induced bronchospasm • Cromolyn is used for asthma but nedocromil is only used as an ophthalmic solution Pharmacodynamics • Cromolyn acts to inhibit mast cell degranulation and also prevents the release of leukotrienes • With continued use, cromolyn reduces bronchi hyper reactivity (important component of asthma) o There is different types of stimulants that can cause this hyper reactivity whether it be allergens, or other environmental irritants o Cromolyn does not have bronchodilator, antihistamine or vasoconstrictor activity and it does not have systemic activity Pharmacotherapeutics • Cromolyn is not a bronchodilator so it is not indicated for the treatment of acute bronchospasm or status asthmatics ADRS • Generally, well tolerated • Can cause some bronchospasms (if that happens, patients can preadminister a beta agonist such as albuterol prior to the administration), throat irritation and coughing • No significant drug interactions with cromolyn Clinical Use • Asthma, bronchospasm prophylaxis, and allergic rhinitis • Asthma – alternative long-term control for mild persistent asthma o If it is used concurrently with bronchodilators, the bronchodilators should be administered first o The effectiveness of cromolyn depends on the patient using it on a regular basis • Bronchospasm prophylaxis – indicated for those who have a known precipitant (exercise or allergies) • Nasal form for allergic rhinitis o Takes 2-4 weeks to produce relief Rational Drug Selection • Based on cost and availability Monitoring • No specific monitoring • Just monitor disease process Patient Education • Cromolyn is not effective if it is not used at regular intervals • Help with a written plan with looking at precipitants of allergies • Demonstrate how to use nebulizer Inhaled Antihistamines • Azelastine and olopatadine • Used for seasonal allergic rhinitis and vasomotor rhinitis Pharmacodynamics • Azelastine is an H1 agonists and a potent inhibitor of histamine release from the mast cells • Olopatadine is a selective H1 receptor antagonist Pharmacokinetics • The exact absorption is unknown, but distribution is suspected to affect the CNS as there is some somnolence reported with azelastine Pharmacotherapeutics • Some patients using intranasal azelastine can have somnolence so caution regarding driving or completing activities that require concentration • Avoid any other OTC meds that also cause CNS depression ADRs • Bitter taste, headache and somnolence Drug Interactions • Added impairment of CNS function with ethanol Clinical Use • Allergic rhinitis Rational Drug Selection • Have fewer ADRs with nasal products compared to oral Patient Education • Prime medication till a fine mist appears • Potential for somnolence Oxygen Pharmacodynamics • Used to treat hypoxia • Hypoxia can be caused by poor ventilation or inadequate partial pressures of inspired oxygen, also inadequate pulmonary function (PE or anemia) • Effects of hypoxia can be observed in all organs of the body o CNS – confusion o Cardiac – increased HR o Lungs – decreases function o Compensation – tachypnea Pharmacotherapeutics • Contraindications in those that are current smokers due to it being flammable • O2 can be prescribed to those with chronic carbon dioxide retention but should be done with caution o Patients with hypercapnia can have sudden increases in their PaCO2 (partial pressure of Co2) produced by oxygen o Can result in death ADRS • Dry nasal passages • Do not put nasal cannula higher than 6L/min or use humidified oxygen • Oxygen toxicity is possible, but it needs to be at 100% oxygen for many days at a time or for those who are in a hyperbaric chamber for that period of time • Neonates – retina of prematurity – damaged due to high levels of oxygen – can cause retrolental fibroplasia Drug Interactions • No drug interactions Clinical Use • Used to provide symptomatic and temporary improvement • Not curative • Different types of oxygen delivery systems o Nasal cannula going at less than 6L/min ▪ Provides 22-40% oxygen o Mask – covers mouth and nose – going at least a 5L/min to avoid accumulation of exhaled air in the mask ▪ Good at 8-10L ▪ Provides 40-60% oxygen ▪ If the patient has an oxygen reverse, it can be higher, up to 100% o Venturi mask – controls the percentage of oxygen delivered to the patient o Can have a hood or a tent Monitoring • If a patient is on oxygen for a long period of time (in the ICU), arterial or mixed venous blood gas is important to see how patient is doing Patient Education • Flammable o Do not smoke • COPD – avoid high altitudes Allergy Medications Antihistamines • Used to treat allergy symptoms specific to the respiratory tract • Known as H1 receptor antagonists • 1950’s: first generation antihistamine • 1980’s: second generation antihistamine Pharmacodynamics • H1 receptor antagonists • Compete with histamine for H1 receptor sites on the effector cells • Prevent but do not reverse responses mediated by histamine • Some of the antihistamines have a strong anticholinergic effect • Antihistamines block the action of histamine that results in increased capillary permeability and formation of edema in the wheels and can also decrease the flare response in peripheral nerve endings. • 1st generation bind nonselectively to the central H1 receptors and therefore cause CNS stimulation and depression o Diphenhydramine (Benadryl) • 2nd generation are selective to peripheral H1 receptors and therefore are less sedating and don’t cross the BBB o Cetirizine (Zyrtec), Allegra, Loratadine (Claritin) • Due to the additional effects that the 1st generation have, they can be used for other causes such as anti- nausea properties, and also Parkinson’s symptoms especially early in treatment. Pharmacotherapeutics • 1st generation: caution in narrow angle glaucoma and lower respiratory tract infections because it can thicken secretions and impair expectoration o Also those with stenosing peptic ulcer, symptomatic BPH, bladder neck obstruction, etc. o Potential for sedation and caution in kids o Can cause a paradoxical CNS stimulation • 2nd generation: caution in 3rd trimester due to potential seizure risk for fetus ADRS • 1st generation: headache, blurred vision and other CNS problems o Also, dry mouth, urinary retention, dysuria • 2nd generation: minimal Clinical Use • Respiratory allergies • Hypersensitivity reactions • Uriticaria and angioedema • Benadryl can be used as sleep aid • Dramamine for motion sickness Rational Drug Selection • 2nd generation preferred due to low side effects Cost • 2nd generation medication costs have gone down Patient Education • Caution regarding sedation Cough and Cold Medications Decongestants • Used with congestion associated with the common cold and allergic rhinitis Pharmacodynamics • Alpha adrenergic receptor agonistics • Produce vasoconstriction by stimulating the alpha receptors within the mucosa of the respiratory tract • Other effects: increase HR, force of contraction & cardiac output • Pseudoephedrine is being replaced because it is a product in the manufacturing of meth • Topical decongestants can shrink the swollen nasal mucosa and cause relief for nasal congestion Pharmacotherapeutics • Contraindicated in patients on MAOI’s because it can cause severe headache, hypertension, hypertensive crisis, hyperpyrexia • Extreme caution with use of decongestants with children ADRS • Minimal with recommended doses • Anxiety, restlessness, tremors, HTN, arrhythmias, nausea and vomiting Drug Interactions • MAOI’s • Beta adrenergic blockers Clinical Use • Nasal congestion Rational Drug Selection • Topical is recommended o Can cause rebound congestion in those using it for more than 5-7 days Antitussives • Used to treat coughs • Coughing is a complex mechanism involving both the CNS and peripheral nervous system and smooth muscle of the bronchial tree • Dextromethorphan and benzonatate Pharmacodynamics • Cough results when there is sensory stimuli irritation of the bronchial tree which stimulates the cough receptors that are located there • Dextromethorphan acts centrally in the cough center in the medulla and elevates the threshold for coughing • Codeine acts directly on the receptors in the cough center of the medulla and is effective but is addictive • Benzonatate anesthetizes the stretch receptors in the respiratory passages so it calms the cough peripherally at its source Pharmacotherapeutics • Medications should be used short term and if there is fever or rash, provider needs to be seen • If patients are allergic to tertricaine and procaine, they should not use benzanotate • Dextromethorphan, codeine and benzonotate can cause drowsiness and dizziness, nausea and GI upset • Codeine can be dependent o Can cause decrease gastric motility Clinical Use • Cough ADRs • CNS depression Expectorants • Guaifenesin Pharmacodynamics • Increases the output of the respiratory tract by decreasing adhesiveness and surface tension, therefore thins the secretions which allows the cilia to work and remove material Pharmacotherapeutics • Not used for persistent cough ADRS • GI upset, drowsiness, nausea, diarrhea, rash, headache Clinical Use • Dry non-productive cough [Show More]

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