Beta 1 Selective Agonists
Stimulation results in
Increased Heart rate and increased force of myocardial contraction (Increased Cardiac output)
To increase cardiac output in emergency situations such as CVS shock or to treat complications in Cardiac Surgery.
also USED FOR
To increase cardiac function in the short-term treatment of certain type of heart disease, - heart failure
Use: Short term mx of Cardiac decompensation that occurs during heart disease or heart surgery. How: Increase force of cardiac contraction. Adm: IV pump infusion (to stable plasma levels)
directly stimulates Beta 1. Low DOSE: cause peripheral vasodilatation. Adm: IV drip to maintain stable plasma levels
Chest pain, difficulty in breathing
Beta 2 Selective Agonists
on bronchiole smooth muscle
Stimulated Beta 2 --> mediates relaxation of bronchioles
Bronchospasm associated with respiratory ailments such as asthama, bronchitis, emphysema. Treats ALSO Cardiac Arrythmias or heart failure
Uterine Muscle (When stimulated-->cause inhibition or relaxation of the uterus)
Beta 2 Selective Bronchodialators
Albuterol (Provventil, Ventolin), Metaproterenol (Alupent,), Pirbuterol (Maxair), Salmeterol (Servent), and Terbutaline (Brethaire, bricanyl).
what it causes
Bronchodilatation at pulmonary smooth muscles - Asthma.
can be the same but: less beta 2 selective and affects beta 1 receptor too.
Oral inhalation so that affects on the bronchial membranes.
nervousness, restlessness, trembling. sometimes fatal asthamatic attaacks.
When used to treat premature labor,
Terbutaline - increase in maternal heart rate and systolic blood pressure, as well as maternal pulmonary edema. Sometimes fatal to mother.
Refers physiological responses related to adrenaline and noradrenaline
Adrenaline and NorAdrenalin = Epinephrine and NonEpinephrine
Stimulate activity in tissues that respond to Epi and NorEpi (Adrenergic agonists) OR inhibit epinephrine and norepinephrine influence (adrenergic antagonists)
From where they release?
Adrenal gland and reach to Heart, Kidneys, and various other tissues and organs via systemic circulation.
Where it is found
Junction between sympathetic postganglionic neurons and peripheral tissues
Subclassification of Adrenergic Drugs
Adrenergic receptors can be divided into two
Alpha and Beta receptors
Five receptor subtypes
Alph 1 (a, b, d) 2 (a, b, c) beta 1,2,3,
Alpha 1 or alpha 2
Located at specific tissues throughout the body--> the responsed depend upon interaction between that receptor andthe reseptive tissue
Increase or mimic the receptor mediated response
decrease the receptor mediated resonce
affects alpha and beta receptors Equally
MIX ALPHA AND BETA
Drugs:Amphetamine (generic), dextroamphetamine (Dexedrine) and methamphatamine (Desoxyn)
Increase Norepi release and decrease NorEpi reuptake and breakdown at adrenergic synapses - so Increase activity at synapses with Norepi sesitive receptors - Alpha 1,2 and Beta1)
Used to treat attention-deficit disorder in children, to increase mental alertness in adults with narcolepsy.
The use to suppress appetite or to combat normal sleepiness is discourage- as they have high potential of abuse
Stimulate Alpha 1, 2 and beta 1 and also stimulate the same by increasing release of norepi at synapses
Use: Primarily for Alpha 1 effects: treat hypotension.
ALSO a nasal decongenstant - stimulate alpha 1: combined with other agents (antitussives, antihistamines) to form cough and cold products
Epinphrine (Adrenalin, Bronkaid Mist, Primatene Mist, )
All receptors are stimulated.
Antiasthmatic inhalation products. - primary stimulate B2 bronchii.
Effect of Alpha 1 vascular
vasoconstirction and control of bleeding during minor surgical procedures (sutures). Prolongs effects of the anasthetics
B1 effect on heart
reestablish normal cardiac rhythm during cardiac arrest.
Drug of choice in Anaphylactic shock
hypersensitive allergic reaction marked by CVS collapse (decreased cardiac output, hypotension) and severe bronchoconstriction.
Becase ability to
Stimulate heart (b1), vasoconstriction periphery (alpha 1) and Dilate bronchi (beta2).
act like Epinephrine
Directly stimulates alpha 1, 2 and beta1
shock or general anasthesia
Stimulates: Alpha 1, 2 and Beta 1.
displays little agonistic activity toward beta2.
Adm IV injection
Treat: Hypotension during shock or general anasthesia.
Nervousness, restlessness, anxiety.
Prolonged use Causes- hypertension, arrhythmias, cardiac arrest.
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Prolonged Use in inhalation: Cause bronchial irritation.
ALPHA 1 SELECTIVE AGONISTS
Alpha 1 or alpha 2
Contraction and VasoConstriction : Increase BP
Maintain/restore BP during hypotensive episodes. Administered: IV or IM injections.
Increase and maintain BP in severe hypotension- during general anesthesia and spinal anesthesia. Treats: Paroxymal sypraventricular tachycardia by causing peripheral vasoconstriction, activation of baroreceptor reflex. Adm : IV injection
Treat: orthostatic hypotension Adm: Orally Also: treat hypotension in patients who go under dialysis, offset the hypotensive effects of psychotropic drugs like antipsychotic medications
Oxymetazoline (Afrin, OcuClear, Many others)
Adm: naslal drops and nasal sprays. Treat: Decrease nasal congestion and decrease redness and minor eye irritation
Phenylephrine (Neo-Synephrine, Others)
Treat: hypotension, treat certain episodes of supraventricular tachycardia. Adm: Orally a lso or nasal spray, or topically as eye drops.
Pseudoephedrine (Drixoral, Sudafed, etc)
Adm: Orally - relieve cold symptoms
nasal spray to decrease congestion during cold and alergies.
increased BP, headache, abnormally slow heart rate, sometimes chest pain, difficulty in breathing, feelings of nervousness
ALHA 2 SELECTIVE AGONISTS
Drug stimulate alpha-2 receptors located at brain and brainstem --> cebtral alpha2 exert an inhibitory effect on sympathetic discharge from the vasomotor center in the brainstem ---> diminished sympathetic discharge results in decreased BP.
Also effective on Spinal cord
Stimulation of Alpha 2 --> causes interneuron inhibition and a subsequent decrease in excitability of motor neurons supplied by interneurons. USE TO normalize the neuronal activity in Spasticity
Adm: local to eye to treat glaucoma. (Decreases vitreous humor production and increasing drainage of vitreous humor from the eye)
Clonidine (Catapres, Duraclon)
Antihypertensive and analgesic, It does not effect ALONE. so given with PRAZOSIN (Minipress - alpha antagonists). also useful to treat severe pain in cancer.
decrease BP (same as Clonidine)
similar to Guanabenz
To treat spasticity. Similar to Clonidine but has fewer vasomotor effects and less likey to cause hypotension and other CVS problems.
Hypotension, dizziness, drowsiness, dry mouth. Difficulty in breathing, slow heart rate, persistent fainting - overdose of drugs.