Selective B2 Agonists Flashcards
B2 agonists
Selectively agonize B2
B2 receptors does what? Stimulate _______increase cAMP which in turn leads to _______(2)
Stimulated activity of adenylyl cyclase
Increase cAMP
1.Relaxation of bronchial smooth muscle/uterine smooth muscle
2. inhibitor of release of mediators of immediate hypersensitivity from cells (mast cells)
*****Selectivity is _____ at high doses and may______
****lost at high doses / High concentration of the agents and they can cause stimulation of B1 receptors at higher doses
One side effect of the heart seen with beta 2 agonists
Tachycardia.
Routes of administration
IV, SC, oral, INH
For bronchodilation effecs, which route is preferred? why?
Inhaled; it delivers the greatest concentration of drug to the lungs and minimizes systemic absorption
What should never be used to treat acute asthma?
LABA
Tocolytics means
To stop premature labor
NEVER USED here in US
ritodrine.
Ritodrine withdrawn in
1998
The only FDA approved Beta2 agonists to use as tocolytics______But currently ______Is used as tocolytics (off label )
Ritodrine: Terbutaline
3 Side effects of b2 adrenergic agonist
- Tremor- Beta 2 in skeletal muscles
- Tachycardia- Due to loss of B2 selectivity at high dosess
- Palpitations
In acute severe asthma, B2 agonists may cause _________how to fix ?
cause a decrease in arterial oxygenation presumed to reflect relaxation of compensatory vasoconstriction
- Give supplemental oxygenation
Beta 2 agonist will cause what in potassium
HYPOKALEMIA
What does beta 2 do to the sodium potassium pump?
drives K intracellular by stimulatin B2 receptors on the Na+ K+ ATPase pump
Drugs interactions
MAOis and TCAs (within 2 weeks of discontinuation)
CLASSIFICATION , how many classes
2 Short acting (SABA) and long acting (LABA)
Short acting B2-adrenergic agonist last?
Last for 6 hours