Chapter 17: Drugs Affecting the Respiratory System
Bronchodilators
Beta 2- Receptor Agonists
• Used to treat reversible bronchoconstriction for all ages of patients 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
l eads to relaxation of bronchial smooth muscle and pulmonary vessels
This study source was downloaded by 100000823822032 from CourseHero.com on 09-01-2021 06:33:19 GMT -05:00
, • 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
Bronchodilators
Beta 2- Receptor Agonists
• Used to treat reversible bronchoconstriction for all ages of patients 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
l eads to relaxation of bronchial smooth muscle and pulmonary vessels
This study source was downloaded by 100000823822032 from CourseHero.com on 09-01-2021 06:33:19 GMT -05:00
, • 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
