Non Catecholamine

Question 0

Ephedrine

1) Indications
2) Onset, DOA, and Half life
3) Metabolism

Answer 0

1) “Intra operative hypotension and bradycardia
Hypotension and bradycardia after spinal/epidural
PONV
Direct action on beta1 = myocardial contractility
Increased CO, SBP, DBP, HR, coronary skeletal muscle BF
Venous constriction >arterial constriction
Decreased RBF and splacnic BF”

2) “Rapid onset
DOA 1 hr
E1/2 t 3hrs”

3) Lacks catecholamines so resistance to COMT = 40% unchanged in the urine

Question 1

Ephedrine

1) Class
2) Action

Answer 1

1) “Synthetic noncatecholamine: Indirect Alpha1 and Beta2 and direct Beta1 adrenergic agonist”

2) “Indirect = Increases NE release from post ganglionic SNS nerve, activate receptor
Direct = binds to receotprs and activates G protein, activates or intracellular enzyme adenylate cyclase to cAMP and phospholipase C – will open ion channel and increase intracellular calcium = vasoconstriction”

Question 2

Ephedrine: Adverse Effects

Answer 2

"Tachyphylaxis
Arrhythmias
HTN
MI
CNS stim
Decreased uterine activity"

Question 3

Ephedrine:

1) Contraindications
2) Dosage

Answer 3

1) "Hypersensitivity
Severe HTN
Arrhythmias
CHF
Glaucoma"

2) 10-25 mg IV
10-50 IM

Question 4

Phenylephrine

1) Class
2) Action

Answer 4

1) “Synthetic Non-catecholamine: Selective Alpha1 adrenergic agonist”
2) Binding to alpha1 receptor = direct stimulation of receptor = G-CP, adenylate cyclase, and cAMP = influx of calcium on systemic VENOUS vascular smooth muscle = vasoconstriction

Question 5

Phenylephrine

1) Indications
2) Onset, DOA, and Half Life
3) Metabolism

Answer 5

1) “Treatment of hypotension in pts with adequate CO and HR
(post neuraxial blockade, anesthesia induction, AS, or CAD)
Nasal decongestant – prevent epitaxis during nasal airway.
Additive to prolong LA
Treat SVT (reflexive action)
Tx hypotenstion post neuraxial blockade
Venous >arterial constriction
Increased MAP, SBP, DBP, SVR and decreased HR”

2) “Onset
3) MAO to phenolic conjugates and 90% via urine

Question 6

Phenylephrine: Adverse Effects

Answer 6

“Rebound nasal congestion
bradycardia
Hypertension, decreased CO bc increased afterload
Decreased renal, splanchnic, cutaneous blood flow
Rebound sinus bradycardia
Anxiety, HA, nervousness, weakness, paresthesia
Decrease UO
Extravasation, necrosis (phentolamine antidote)
Metabolic acidosis”

Question 7

Phenylephrine

1) Contraindication
2) Dosage

Answer 7

1) "Hypersensitivity
Glaucoma
Severe HTN and tachycardia
arrythmias
Caution in elderly, heart blocks, HTN, bradycardia,"

2) “50-200mcg IV bolus Q5mins
20-50 ug/min
DOUBLE DILUTE”