Direct-acting adrenoceptor agonitst - noncatecholamines Flashcards
Noncatecholamines - MOA
Bind to and activate adrenoceptors
Noncatecholamines - 3 groups
α1-agonists.
Selective β2-adrenoceptor agonitsts.
Imidazoline drugs.
α1-adrenoceptor agonists - 2 drugs
Phenylephrine.
Midodrine.
Main difference between catecholamines and noncatecholamines
The noncatecholamines are not substrates for COMT, and some are resistant to MAO degradation.
Phenylephrine - indications
Viral and allergic rhinitis. Allergic conjunctivitis.
Mydriasis for retinal examination.
Surgery to maintain BP.
Hypotension.
Drug-induced, septic and neurogenic shock.
Benefits of using phenylephrine for eye examinations
Produces mydriasis without disrupting accommodation.
Midodrine - indications
ONLY hypotension - orthostatic (e.g. severe diabetic autonomic neuropathy), caused by infections in infants, induced by psychotropic agents, pts on renal dialysis.
Midodrine - adverse effects
Hypertension in supine position.
Selective β2-adrenoceptor agonitsts - 2 drugs + 1 group
Albuterol (salbutamol).
Terbutaline
Long-acting β agonitsts (LABAs).
LABAs - 6 drugs
Pirbuterol. Fenoterol. Formoterol. Arformoterol. Levalbuterol. Salmaterol.
Selective β2-adrenoceptor agonitsts - indications
Asthma
COPD
Selective β2-adrenoceptor agonitsts - adverse effects
Tachycardia.
Muscle tremor
Nervousness
Selective β2-adrenoceptor agonitsts - administration
Inhalation.
also other adm routes for individual drugs
Selective β2-adrenoceptor agonitst that is indicated for other disorder than respiratory tract disorder.
Terbutaline. Indicated for tocolysis (prolong premature labor 1-2 days)
Terbutaline - adm and adverse effect
Injection - maternal heart problems
Terbutaline - contraindication
Prevention of labor or prolonged treatment.
Imidazoline drugs - 5 drugs
Oxymetazoline. Apraclonidine. Brimonidine. Clonidine. Dexmedetomidine.
Imidazoline drugs - MOA
Activate α-adrenoceptors and imidazoline receptors.
Imidazoline drugs used to decrease intraocular pressure after surgery
Apraclonidine, brimonidine.
Imidazoline drugs used as nasal and ocular decongestant, and its contraindications
Oxymetazoline.
Careful in pts with HT or heart disease. Do not use more than 5 days. Caution on children and elderly.
Oxymetazoline - adverse effects
Rebound congestion.
CNS and cardiovascular depression.
Why are apraclonidine and brimonidine not used for glaucoma?
High rate of tachyphylaxis
Clonidine - indications
Hypertension.
Opioid abstinence.
Dexmedetomidine - indications
Sedation of intubated pts.
Adjunct to anesthesia.
