Myocardial ischaemia (stable angina)

Question 1

what are the two different categories of nitrates?

Answer 1

short- acting nitrates
long- acting nitrates

Question 2

What are short- acting nitrates used to treat?

Answer 2

acute angina attacks

Question 3

What are long- acting nitrates used to treat?

Answer 3

long term prophylaxis of angina

Question 4

what are examples of short- acting nitrates?

Answer 4

glyceryl trinitrate
isosorbide dinitrate (S/L)

Question 5

What are examples of long- acting nitrates?

Answer 5

MR Isosorbide dinitrate
isosorbide mononitrate

beta- blockers
calcium channel blocker
ivabradine
ranolazine
nicorandil

Question 6

what is the mechanism of action of glyceryl trinitrate?

Answer 6

converted to nitric oxide which is a short acting vasodilator; improves blood supply

Question 7

what are the formulations of glyceryl trinitrate?

Answer 7

sublingual tablet*/ spray

*special container for sublingual tablets. Expires 8 weeks after opening. Foil- lined container with no cotton wadding

Question 8

How long do the effects of glyceryl trinitrate last for?

Answer 8

effects last 20-30 minutes

if using more than twice a week- long term prophylaxis

Question 9

When should glyceryl trinitrate be taken?

Answer 9

when required OR before angina- inducing activities e.g. exercise

Question 10

How should glyceryl trinitrate be taken?

Answer 10

the patient should SIT down as otherwise dizziness can occur

Take 1st dose under tongue and wait 5 minutes
Take 2nd dose under tongue and wait 5 minutes
Take 3rd dose under tongue and wait 5 minutes

(dose is either 1 tablet OR 1-2 sprays)

If pain is still present after 3 doses call 999

Question 11

What is used for angina prophylaxis?

Answer 11

B- Blocker or CCB e.g. diltiazem

B- Blocker + dihydropyridine CCB (amlodipine, MR nifedipine, felodipine. Max 2 drugs. —> if one or both is contraindicated add/use vasodilator

Vasodilator:
- long acting nitrate
- ivabradine (only in normal sinus rhythm)
- ranolazine
- nicorandil in adults only (K- channel activator)*

*MHRA/ CHM warning (Jan 2016): now given second line as risk of ulcer complications, mouth, skin, eye, gastrointestinal.
ALSO not drive until it is estabilished performance is not impaired

Question 12

What are nitrates?

Answer 12

nitrates are potent coronary vasodilators and reduce venous return and cardiac output

Question 13

how is isosorbide mononitrate taken?

Answer 13

BD
unless MR preparation: OD

Question 14

how is MR isosorbide dinitrate taken?

Answer 14

BD

(also active sublingually; alternative to glyceryl trinitrate)

Question 15

How can we ensure patients dont develop tolerance to nitrates?

Answer 15

need to use long acting preparations or transdermal patches
maintain effectiveness by reducing blood nitrate concentrations to low levels for 4 to 12 hours a day

Can do this by either

1. leave patches off for 8-12 hours (overnight) in a day
   OR
2. take second dose after 8 hours not 12 hours for MR isosorbide dinitrate (BD) and isosorbide mononitrate (BD)
   OR
3. take MR isosorbide mononitrate as this is taken OD and therefore does not produce tolerance

Question 16

what are side effects of nitrates?

Answer 16

vasodilation, flushing, throbbing, headache, dizziness, postural hypotension, tachycardia, dyspepsia, heartburn

Question 17

what are site effects of injection (GTN and isosorbide dinitrate in MI)

Answer 17

severe hypotension, sweating, apprehension, restlessness, muscle twitching, retrosternal discomfort and palpitations

Question 18

why should we avoid abrupt withdrawal of nitrates and CCB?

Answer 18

worsens angina