Tx of Asthma And COPD, antihistamines Flashcards
Asthma
narrowing of the airways, esp small airways
involves reversible airway obstruction, inflammation & increased airway responsiveness to a variety of stimuli
Inflammation in asthma contributors (4)
INFLAMMATORY CELLS: leukocytes, mast cells, EOSINOPHILS, neutrophils, alveolar mactophages & lymphocytes are seen in the airways
PROSTAGLANDINS: prostaglandin D2 is a potent bronchoconstricor
INTERLEUKINS-4,5 & 13: attract & activate eosinophils & stimulate IgE production by B lymphocytes
LEUKOTRIENES: liberated during inflammation in the lunch, cause bronkoconstriction & edema
PLATELET-ACTIVATING FACTOR: causes immediate bronchoconstriction & sustained airway hyperreactivity, edema & chemotaxis of eosinophils. selective antagonists are being developed
-also increased mucus production
often used to diagnose and characterize asthma
increased responsiveness to challenge with METHACHOLINE, HISTAMINE & EXERCISE are often used to dx and characterize asthma
B2-Adrenergic Agonists
MOST EFFECTIVE bronchodilators
B2 receptor stimulation ACTIVATES ADENLYATE CYCLASE & INCREASES cAMP, which causes RELAXATION OF SMOOTH MUSCLES IN THE BRONCHIOLES & STABILIZATION OF MAST CELLS
generally given by INHALATION, which restricts action to the lung & increases the speed of action, important in relieving bronchospasm
selective B2 agonists
are more effective at stimulating B2 receptors (of the lungs) than B1 (of the heart)
First line tx for asthma
selective B2 agonists
name the 3 fast-acting (immediate effect) beta 2 agonists
what is their duration of action
Albuterol (Ventolin)
Levalbuterol (Xopenex)
Pirbuterol (Maxair)
duration of action: 4-8 hours
Salmeterol (Servent)
- lasts for 12 hours
- very BRONCHOSELECTIVE & designed to have a long duration of action
- decrease likelihood of bronchospasms & for nocturnal asthma
- given PROPHYLACTICALLY on a CHRONIC BASES
- a CORTICOSTEROID SHOULD ALWAYS BE GIVEN IN CONJUNCTION
effects take abt 20 mins to occur
so NOT EFFECTIVE FOR THE RELEIF OF ASTHMA ATTACK IN PROGRESS
pts need a fast acting bronchodilator (rescue inhaler)
Formoterol
long acting bronchodilator, like salmuterol
Advair (salmeterol/fluticasone)
intermediate acting bronchodilator & corticosteroid
salmeterol should always be given with a corticosteroid
pts will need a fast acting rescue inhaler too
Dulera (formoterol/mometasone)
long acting bronchodilator + a corticosteroid
-pts should be given a fast acting rescue inhaler (-buterol) in addition to this
Inhaled selective B2 agonists SEs
the have very few
tachycardia
nervousness & dizziness
tremor
generally ppl become tolerant to these effects & they are often short-lived
B2 agonist controversies
TOLERACE TO B2 agonists could occur w/long-term tx, but this is more of a prob in places other than the lungs
CONCOMITANT use of CORTICOSTEROIDS can prevent & in fact reverse, the phenomenon of tolerance & prevent loss of B receptors
so, unless B agonists are used only on an as-needed basis, standard practice is to combine them with an inhaled steroid
Ipratropium (Atrovent)
class
absorption
activity
USE
- Muscarinic antagonist
- QUATENARY compounds, not absorbed systemically but STAY IN THE LUNG
bronchodilation develops more SLOWLY than with the B2 agonists
USE:
- widely for COPD or emphysema
- used in conjunction with a B2 agonists when B2 alone is not sufficient to tx sxs or if pt cannot tolerate B-agonists
Combivent
Iptratroprium (muscarinic antagonist) combined w/ Albuterol in one spray
Tiotropium (Spiriva): what is it?
similar to ipratropium (muscarinic antagonist)
has a longer duration of action & only needs once a day administration
-may work in some patients who do not respond as well to ipratroprium
Theophylline (Theo-Dur)
class
2 main actions (contributing to therapeutic effect)
therapeutic effect
therapeutic index
CNS stimulant acts like caffeine-decreases fatigue, elevates mood
- BLOCKS ADENOSINE RECEPTORS, which normally cause bronchoconstriction & inflammation
- inhibits PHOSPHODIESTERASE, increases amt of cAMP, similar to beta2 stimulation
very effective bronchodilator, RELAXES SMOOTH MUSCLE< ESP BRONCHIOLES, stimulates cardiac muscle & acts as a diuretic in the kidney
-used in pts who don’t respond sufficiently to B2 agonists alone in COPD
VERY LOW THERPEUTIC INDEX
Theophiline (The-Dur) pharmokinetics: administration, elimination, affected by
given ORALLY in sustained release prep
rate of absorption varies, so ONCE A DOSE IS ESTABLISED, IT IS BETTER NOT TO SWITCH BETWEEN BRANDS (prob. w/ generic prescribing)
eliminated by liver
- clearance increased 2x by phenytoin
- smoking, rifampin, & oral contraceptives also increase clearance of theophylline
cimetidine DECREASES clearance
Theophylline: side effects & toxicity
CNS: NERVOUSNESS, INSOMNIA, similar to caffeine, anxiety & tremors can occur
Cardiac: increases rate & force of contraction; in higher doses, can cause tachycardia & may predispose to ARRHYTHMIAS
MUSCLE: increases contractility of diaphragm & decreases fatigue
weak diuretic effect
Toxicity: overdose can be fatal (U) due to arrhythmias & seizures
Corticosteroids: use in asthma
-used to DECREASE INFLAMMATION in airways
should ALWAYS be included with long acting B2 agonists
IMPROVE SYMPTOMS & DECREASE THE REQUIREMENTS FOR BETA-AGONISTS
beneficial effects begin in 1 wk, improvement can continue for months
oral steroids used in severe cases of asthma, when other things are not enough;
oral steroids often used for SHORT PERIODS of EXACERBATION to BRING SYMPTOMS INTO CONTROL, may be used prophylactically (U) do not cause serious SEs when used short term
5 inhaled steroids
Beclomethasone Flunisolide Triamcinolone Fluticasone Budesonide
Inhaled steroids: side effects
oropharyngeal candidiasis (THRUSH)
HOARSENESS is common
modest decrease in BONE DENSITY in women
Oral Steroids (2)
Methylprednisone
Prednisone