All details about antianginal

1. Prepared by:
Dr. Sanjay Gupta
© Copyright

2. Antianginal Drugs:
 Drugs that prevent, abort or terminate attack of angina
pectoris.

3. ANGINA PECTORIS:
A pain syndrome due to induction of an adverse oxygen
supply/demand situation in the portion of myocardium.
Two principal form of angina is
i. Classical angina:
 Attacks are predictably provoked by exercise, emotion,
eating or coitus and subside when the increased energy
demand is withdrawn.
 The underlying pathology is severe atherosclerotic affliction
of larger coronary arteries.
 This coronary obstruction is decrease blood flow during
increased demand despite local factors mediated dilatation
of resistance vessels and ischaemic pain is felt.

4. ii. Varient/Prizmental’s angina (uncommon form):
 Attacks occur at rest or during sleep and are
unpredictable.
 They are due to recurrent localized coronary
vasospasm which may be superimposed on
arteriosclerotic coronary artery disease.
 Unstable angina with rapid increase in duration and
severity of attack is mostly due to atheromatous
plaque attracting platelet deposition and progressive
occlusion of coronary artery.

6. NITRATES (GTN)
All organic nitrates have same action, differ only in time course.
Action: Direct nonspecific smooth muscle relaxation.
Dilates veins more than arteries – decrease venous return – preload on
heart decreased
Afterload reduction – Nitrates also produced arteriolar dilatation –
decrease t.p.r or afterload on heart
Redistribution of coronary flow
Reduce cardiac work
MOA: Organic nitrates are rapidly denitrated enzymatically in the smooth muscle
cell to release the reactive free radical nitric oxide (NO)
https://www.youtube.com/watch?v=MyXuvis4hN4

8. PK: Organic nitrates are lipid soluble, well absorbed from buccal mucosa,
intestine and skin.
GTN and isosorbide dinitrate are short acting from sublingual route but
longer acting from oral route.
AE: AE mostly caused due to vasodilation.
Fullness in head, flushing, weakness, sweating, palpitation.
tolerance develops, methemoglobinemia, rashes.
Dependence: Sudden withdrawal after prolonged exposure has resulted in spasm
of coronary and peripheral blood vessels.
Interaction: Sildenafil cause dangerous potentiation of nitrate action: severe
hypotension, MI and deaths are on record.

9.  GTN – Glyceryl trinitrate (Nitroglycerine)
 Volatile liquid.
 Used trough sublingual route (tablet & spray).
 Sustain release oral capsule is used for chronic
prophylaxis.
 Transdermal patch is also available.
 Direct absorption into systemic circulation.
 Plasma t1/2 is 2 min.
Use: Unstable angina, coronary vasospasm,
MI and Hypertension during cardiac surgery

10. ISOSORBIDE DINITRATE
 Solid drug with similar property to GTN
 Can be used sublingually at the time of attack
 Well absorbed orally
 Slight slower action than GTN, Peak in 5-8 min
 Oral dose is used for chronic prophylaxis
ISOSORBIDE MONONITRATE
 Active metabolite of isosorbide dinitrate
 When administered orally it undergoes little first pass
metabolism.
 BA is high, longer acting

11. β-BLOCKERS (propranolol, atenolol etc)
 They do not dilate coronary or other blood vessels.
 Coronary flow reduced due to β2-blockade.
Action: reduce cardiac work
reduced the O2 consumption
↓ HR, Fall in BP
↓ frequency and severity of attacks

12. CALCIUM CHANNEL BLOCKERS
 All CCBs are effective in reducing frequency and
severity of classical as well as variant angina.
 Benefit is caused due to reduction in CO and afterload
 CCBs are not 1st line of drugs in unstable angina.
 Prescribed with nitrates when coronary vasospasm is
prominent and not controlled by Nitrates alone.

13. POTASSIUM CHANNEL OPENER (Nicorandil)
MOA:
They open K+ Channel and reduces intracellular K+ conc.
Action: Smooth muscle relaxation
NICORANDIL: Novel anti-anginal drug
MOA: Activates ATP sensitive K+ Channels –
Hyperpolarize smooth muscle
NO donar also – relax blood vessels
Action: Beneficial effects on angina
Increase exercise tolerance
Myocardial protection
SE: Palpitation, flushing, weakness, headache, dizziness,
nausea, vomiting.

14. Other Anti-Anginal Drugs
 TRIMETAZIDINE
 Novel anti-anginal drug
 Reduce angina frequency and increase exercise capacity
 MOA – Not known
 PK: Absorbed orally, well tolerated
t1/2 – 6hr,
 SE: gastric burning, dizziness, fatigue and muscle cramp
 Reversible parkinsonism in elderly
DIPYRIDAMOLE, OXYPHEDRINE