Respiratory and GI Flashcards
Classes of Drugs Used to Rx Respiratory Disease
*Antitussives
*Mucolytics & Expectorants
*Decongestants
*Antihistamines
*Bronchodilators
*General airway anti-inflammatory
Pathophysiology of Respiratory Disease
*Allergies and Upper RT hypersensitivity reactions
*Overt Infections –> Upper respiratory tract vs Pneumonia
*Obstruction lung disease (Asthma, Emphysema, Chronic bronchitis)
*Restrictive lung disease
What do Antitussives do?
suppress cough, allow patient to sleep, generally decrease cough reflex
Side effects of antitussives
sedation, but not habit forming
Dextromethorphan (Tussin):
centrally acting analgesic
What do Mucolytics do?
decrease the viscosity of mucous so it can be coughed up
Most common Mucolytic
Acetylcystine (Mucomyst):
* most common, given by inhalation or intratrachealinstillation
* breaks disulfide bonds and acts as antioxidant
What do expectorants do?
increase mucous production and ejection
Expectorant Medication
*Guaifenesin: FDA approved expectorant
Trade name: Mucinex
Mucinex DM
combined with dextromethorphan
Mucinex Sinus Max
combined with phenylephrine
What do decongestants do?
*Decrease airway resistance
*Constrict nasal and sinus blood vessels, thus decreasing blood flow
and fluid extravasation
Types of decongestants
Ephedrine
Oxymetazoline
Phenylephrine
Phenyylpropanolamine
Pseudoephedrine
Decongestants are all…
Alpha-adrenergic agonists that cause vasoconstriction of nasal blood vessels
common side effects of decongestants
tachycardia, nervousness, insomnia
which medications are locked up so you dont make meth?
decongestants
What do antihistamines do?
*Decrease nasal and sinus secretion
*Decrease mucosal irritation, discharge & cough
*Decrease conjunctivitis
*Decrease pressure, pain & edema
How do antihistamine work?
by blocking histamine receptors
*H1 receptors on respiratory and GI smooth muscle
* H1 R involved in blood vessel permeability and dilation
*H2 receptors on gastric mucosa (acid secretion)
*H3 receptors in CNS
Main side effect of antihistamines
*Drowsiness
*Sleepiness
*Newer antihistamines such as Claritin and Zyrtec are reported to cause less drowsiness
Airway obstruction is a problem in….
asthma, chronic bronchitis & emphysema
What are the 1st drugs used to treat obstructive pulmonary disease?
beta2 Agonists, Anticholinergics, Cromones & Xanthines
What other two drugs can be used treat obstructive pulmonary disease
Chromones and anti-inflammatories
Albuterol
Beta2 agonists given by metered dose inhaler (MDI) potent and rapid acting bronchodilator
-may be difficult to administer
Ipratropium (Atrovert)
new anticholinergic (anti-muscarinic)
-administered by inhaler so less systemic spread, fewer SE
-recent study shows it puts males at risk for urinary retension
*Blocks cholinergic-mediated PSNS bronchiolar
constriction
*Not as effective as beta2-agonists for asthma, but useful with other COPD conditions or combined with beta2-agonists
Theophylline (Theo-Dur)
bronchodilator, increases respiratory muscle strength, increases mucocilliary transport, decreases pulmonary artery P, decreases histamine release
-works by inhibiting PDE enzyme (inhibits break down of cAMP)
- Oral, extended release oral
see mechanism of action of bronchodilators
slide 13
Onset and duration of albuterol
on set: 5-15 mins
duration: 3-6 hrs
Ipratropium (Atrovent) side effects
similar to those seen with other
anticholinergics (constipation, dry moth, visual
disturbances, mental status changes, etc…)
Cell targets of drugs for airway obstruction
- Histamine
- Leukotrines
- Thromboxanes
- Cytokines
- White blood cells (neurtophils, T-cells and macrophages)
Airway anti-inflammatories include:
- drugs that block cellular & prostaglandin-
mediated airway constriction and irritation
*All are glucocorticoids
side effects of airway anti-inflammatories
Catabolic effects
*breakdown of supporting tissues
*muscle wasting
*Other SE: glucose intolerance, cushingoid changes, HTN, osteoporosis, loss of adrenal fx
*Some can be given by inhalation to limit systemic effects
Glucocorticoids - Cortisone
- Trade name: Cortone
- Oral and IM
Generic names of glucocorticoids
- Bethamethasone
- Cortisone
- Flunisolide
- Triamcinolone
Cromones - Cromolyn Sodium
*used prophylactically to prevent bronchospasm in asthma
*does not reverse bronchoconstriction in asthma attack
*mechanism u/k, but thought to prevent release of inflammatory mediators (prostaglandins, histamine)
*administered by MDI and nebulizer
*very few side effects
*frequently used to Rx asthma in children
Side effects of Beta 2 agonists
tachycardia, nervousness, sleeplessness,
*chronic use- increased bronchospasm
side effects of anticholinergic drugs
constipation, urinary retention, dry mouth,
blurred vision, tachycardia, confusion
Side effects of Xanthines
CNS stimulators (Theophylline- caffeine like
compound w/ similar S.E.), sleeplessness, nervousness and toxicity: N&V, confusion, seizures, death* (with toxicity)
***Very narrow therapeutic window
side effects of corticosteroids
even w/ inhalation, produce muscle
wasting, osteoporosis, exacerbation of DM, etc…
Common GI conditions treated with drugs
heart burn, acid reflux, ulcers, constipation, diarrhea and nausea & vomiting
Most GI problems fit into one of these categories:
*excessive GI motility/secretion
*heart burn, diarrhea, acid reflux, ulcer, some cases of N&V
*diminished GI motility/secretion
*constipation, some cases of N&V
Gastrointestinal Agents - Antacids
decrease or neutralize stomach acid
* Ranitidine (Zantac): H2 blocker for ulcer & GERD
Gastrointestinal Agents - Laxatives and Cathartics
slow and fast acting agents
used to promote bowel movement
Gastrointestinal Agents - Antidiarreal
Loperamide (Imodium): slows GI tract
motility and secretion
Gastrointestinal Agents - Emetics
induce vomiting: ipecac- central acting
Gastrointestinal Agents - Antiemitics
inhibit vomiting: Ex: scopolamine
Basic strategy of treatment of heart burn/acid reflux and ulcer
Antiacid + Hydrochloric acid → Salt + water
H2 receptor blockers
*Used for dyspepsia, gastroesophageal reflux
*Few side effects and well tolerated
*Many were initially prescription, but now OTC.
What are proton pump inhibitors
Newer class of drugs that specifically inhibit the K+/ H+ exchanger or “proton pump” that pumps H+ into the lumen of stomach
What other effect does proton pump inhibitors have?
anti-bacterial effect against Helicobacter Pylori
Adverse reaction to PPIs
- Generally well tolerated. Common adverse effects: headache, nausea, diarrhea, abdominal pain, dizziness
Adverse reactions to PPIs for longer term use
- Decreased vitamin B12 absorption may occur with long-term use. It has been observed that gastric acid suppression, using H2-receptor antagonists and proton pump inhibitors, is associated with an increased risk of community-acquired pneumonia.
- Increase risk of Clostridium difficile infection with even once daily use and even higher risk with > once/day use
- Long-term use of proton pump inhibitors may increase risk of osteoporosis
New guidelines for PPIs
- Acknowledge that PPIs are frequently overused, and may be taken for longer that absolutely required
- Stress appropriate PPI usage:
- PPIs be taken at the lowest dose
- shortest duration for the condition
Laxatives and Cathartics Drugs
- Psyllium (Metamucil): Bulk: fiber that absorbs water
- Bisacodyl (Dulcolax): direct irritant to GI wall
Anti-Diarrhea medications
Loperamide (Imodium) –> opioid
What are antiemetics used for?
to help patients being treated with chemo
Rx or Radiation Rx experiencing N&V
How to anti-emetics work?
by blocking histamine or
acetylcholine R’s or act centrally to diminish
dopamine neurotransmission
Post GI resection CF:
Oral replacement of pancreatic
enzymes
Crohn’s Disease and IBD
- Glucocorticoids,
- Anti-inflammatories
- Adrenergic inhibitors
- TNF inhibitors and biologics
Most effective drugs for IBD and Crohn’s disease
tumor necrosis factor (TNF)-alpha inhibitors, or “biologics”
* Monoclonal antibodies that bind and neutralize TNF
* Examples include: Infliximab (Remicade), adalimumab (Humira) and golimumab
(Simponi)- Infliximab added to “DTK” list under “Biologics”
How is infliximab given?
IV
but duration is 6-12 weeks
what is infliximab used to treat?
RA, psoriatic arthritis, UC, Crohn’s disease, ankylosing spondylitis and psoriasis
adverse effects of Infliximab
hypersensitivity reactions, HA, abdominal pain,
anemia, infection (especially respiratory) and flushing
Adverse effects of orlistat
*Malabsorption of vitamins and minerals: Especially fat-soluble vitamins like A, D, E
*HA, flatulence with discharge, fatty stool, fecal incontinence, increased defecation, abdominal pain/discomfort
*Drug interactions: may interfere with warfarin dosage (increase need to check PT/INR)
general side effects of antacids
All associated with “acid rebound”
general side effects of H2 blockers
side effects rare except for Cimetidine
General side effects for PPIs
few side effects, but caution with long term use
General side effects of antidiarrheal agents
nausea, abdominal discomfort,
constipation, drowsiness, fatigue, dizziness, potential for addiction/tolerance
general side effects of laxatives
nausea and cramps: prolonged use- lower GI
irritation, spastic colitis, water and electrolyte imbalance, acid-base imbalance, loss of normal bowel function & addiction
