Cardiac Flashcards
1
Q
nitroglycerine
A
- venous vasodilator > reduces preload
- nitric oxide system: GTP > cGMP > decreased Ca++
- 1 hour onset, lasts 2-12 h
- topical ointment (2%); applied on the pinna of ears for cats; hepatic metabolism; wear gloves, can cause a rash/hypotension
2
Q
isosorbide dinitrite
A
- venous vasodilator > reduces preload
- for angina, congestive heart failure
3
Q
hydralazine
A
- arterial vasodilator > reduces afterload
- block IP3 pathway: PLC > block IP3 > no Ca++ from SER
- 1h onset, peaks at 3h, lasts 8-10h
- extensive hepatic metabolism; can cause tachycardia
4
Q
amlodopine
A
- arterial vasodilator > reduces afterload
- calcium channel blocker
- t 1/2 long, 35h, peak 6h
- oral; dihydropyridine; cats mainly (dogs too), hepatic metabolism
5
Q
nitroprusside
A
- balanced vasodilator
- nitric oxide system: GTP > cGMP > decreased Ca++
- t 1/2 short, minutes
- IV, CRI; potent; to lower left atrial pressure; metabolized to cyanogen; eliminated in urine, feces, exhalation; can cause cyanide toxicity
6
Q
prazosin *
A
- balanced vasodilator
- treats congestive heart failure or hypertension
- alpha 1 antagonist
- peak 2-3 hours
- oral; reduces peripheral vascular resistance; metabolized via liver, excreted in bile/feces; not used frequently
- also, in autonomic: treats urinary retention by relaxing sphincter (faster and better than phenoxybenzamine)
7
Q
enalapril *
A
- balanced vasodilator
- ACE inhibitor (RAAS)
- onset 4-6h, lasts 12-14h
- excretion 95% renal; pro-drug; compete with angiotensin I for Ace binding site; monitor renal; not well absorbed by horses; hyperkalemia, low GFR
8
Q
sildenafil *
A
-pulmonary vasodilator
-PDE5 inhibitor
-t 1/2 6 hours
= Viagara
9
Q
benazepril *
A
- balanced vasodilator
- ACE inhibitor (RAAS)
- onset 1.5h, dogs 4h, cats 16-23h
- renal and biliary excretion; treats systemic hypetension; pro-drug; compete with angiotensin I for Ace binding site; monitor renal; hyperkalemia, low GFR
10
Q
quinidine
A
- class Ia anti-arrhyth.
- blocks sodium influx > prolongs AP duration
- treats supraventricular and ventricular arrhythmia
- t 1/2 5-6h
- for conversion of fibrillation in horses; extensively protein bound; competes with digoxin’s binding site; lots of hypotension and GI disturbances in dogs
11
Q
procainamide *
A
- class Ia anti-arrhyth.
- blocks sodium influx > prolongs AP duration
- treats supraventricular and ventricular arrhythmia
- t 1/2 3h
- abolishes SVT; second choice after lidocaine for life threatening V-tach; less cardio-depressant than quinidine; occasional GI upset with oral; limited avail.
12
Q
lidocaine *
A
- class Ib anti-arrhyth.
- blocks sodium influx > prolongs AP duration
- treats ventricular tachyarrhythmia
- IV bolus lasts 10-20 min
- first choice for life threatening ventricular tachyarrhythmias; IV only; high first pass metabolism; CNS excitement and seizures; cats more sensitive
- also, in anesthesia
13
Q
mexiletine
A
- class Ib anti-arrhyth.
- blocks sodium influx > prolongs AP duration
- ventricular arrhythmia (VPC)
- t 1/2 3-4h
- oral, 85% bioavailability, less 1st pass metabolism than lidocaine; GI (vomiting) issues, reduced if given with food; CNS signs at high doses; no neg. inotrope like sotalol
14
Q
flecainide
A
- class Ic anti-arrhyth.
- blocks sodium influx > prolongs AP duration
- not used often, this is one example of a class IC
15
Q
propanolol
A
- class II anti-arrhyth.
- blocks beta adrenergic stimulation (slow AV nodal cond.)
- treats supraventricular and ventricular arrhythmia
- t 1/2 2h
- also decreases ventricular contraction vs. atropine that doesn’t; dose dependent; bronchoconstriction; do not combine with calcium channel blockers (both negative inotropes); liver exc.
