high risk drugs in arrhythmia

Question 1

amiodarone moa

Answer 1

class 3 anti arrythmic= k+ channel blocker

Question 2

half life of amiodarone and loading dose

Answer 2

1/2 life= 50 days
loading dose= 200mg tds for 7 days
200mg bd for 7 days
then 200mg OD maintenance

Question 3

interactions and amiodarone

Answer 3

there is a danger of interactions after stopping due to half life long

Question 4

Warning signs

Answer 4

1) corneal micro deposits - dazzled by headlights,. stop if vision impairment or neuropathy
2) photosensivity= erythema/ slate grey skin use discolouration on light exposed area broad spec high spf and hide skin
3) peripheral neuropathy
4) thyroid dysfunction i.e hypo or hyper
5)sob or cough- pulmonary toxicity
6) hepatotoxic = jaundice etc and 3x ALT

Question 5

Why can amiodarone effect thyroid function

Answer 5

contains iodine
if causes hypo= give levothyroxine without withdrawing amiodarone if essential
if hyper = give carbimazole but amiodarone must withdraw

Question 6

food interaction amiodaroen

Answer 6

grapefruit juice

Question 7

monitoring with amiodarone

Answer 7

lFT- 6months
TFT- every 6 months
EYE TESTS- ANNUAL
cxr -before tx
serum potassium - causes hypokalaemia remember (DIBTC)
ECG with iv use can cause bradycardia
BP = hypotension

Question 8

interaction amiodarone increases the plasma conc of

Answer 8

coumarin, dabigtran , digoxin- half dose, , felicaide, propafenone, phenindione

Question 9

what increases plasma conc of amiodarone enzyme inhibitors SICKFACES.COM

Answer 9

grapefruit juice

Question 10

inc QT prolongation with amiodarone

Answer 10

COLLAPSE
chlorquine, ondasteron, levofloxacin, loratidine, amiodarone, psychiatric (haloperidol) , sertraline (antidepressant, TCA), erythromycin

Question 11

AMIOadarone interaction with simvastatin causes

Answer 11

myopathy change dose

Question 12

amiodarone causes bradhycardia and myocardial depression with what drugs

Answer 12

BB, RLCCB (diltiazem verapamil)

Question 13

digoxin moa

Answer 13

inhibit sodium potassium pump , increase myocardial contraction and reduces conductivity AVN= decrease HR

Question 14

therapeutic range digoxin and when to measure, dosing

Answer 14

0.8-2mg/l (6hr after 1st dose)
loading dose is given due to long 1/2 life and rapid digitilisation

Question 15

route of excretion and metabolism

Answer 15

metabolism into active= hepatic
and renally excreted

Question 16

why not to switch forms straight up for digoxin

Answer 16

diff forms have diff Bioavailability

Question 17

digoxin dose based on indication

Answer 17

AF or non paroxysmal in sedentary = 125mcg-250mcg
worsening or severe HF= 62.5-125mcg

Question 18

warning signsdigoxin toxicity

Answer 18

1) cardiac - bradycardia/ arrhythmia
2) gi - abd pain, n/v
3) neurological - lethargy dizzy psychosis
4) visual - blurred / or yellow vision

Question 19

monitoring digoxin toxicity

Answer 19

electrolyte- hypomagnesia,hypokalaemia, hyper calcaemia (toxicity)
rft - renal clears low dose elderly
hr (bp >60)

Question 20

does digoxin require regular monitoring

Answer 20

no regular tdm - required unless signs toxicity or renal impair/ elderly

Question 21

digoxin interaction mnemonic

Answer 21

crased= ccb , rifampicin, amiodarone,,st john wort, erythromycin, diuretic

Question 22

reduce dose by half (digoxin)

Answer 22

amiodarone, dronedarone, quinine

Question 23

reduce plasma conc digoxin

Answer 23

rifampicin, st john wort

Question 24

increase toxicity digoxin (due to hypokamlameia)

Answer 24

DIBTC - if <k+ 4.5 give potassium supplement or switch to potassium spare diuretic

Question 25

nephrotoxicity with digoxin

Answer 25

CARNIVAL CAMP

Question 26

inc plasma conc of digoxin

Answer 26

amiodarone ciclosporin, quinine,, mirabegron, macrolide, itraconzaloe, macrolides, ccb ,spironolactone