pharm D 2nd year - Pharmacotherapeutics I

1. REVASCULARISATION
PERCUTANEOUS TRANSLUMINAL CORONARYANGIOPLASTY
• PTCA has been used successfully in the management of angina.
• It involves the insertion of a guidewire and inflatable balloon into the
affected coronary artery and enlarging the lumen of the artery by stretching
the vessel wall.
• This frequently causes atheroma plaque fracture by stretching inelastic
components and denuding the endothelium, resulting in loss of nitric oxide
and other vasodilators and exposure of plaque contents to the vascular
compartment.
• During PTCA, patients usually are heparinized to prevent immediate
thrombus formation at the site of arterial injury and on coronary guidewires
and catheters; anticoagulation is continued for up to 24 hours.
• The intensity of anticoagulation is monitored using the activated clotting
time (ACT), and the targeted range for ACT is 250 to 300 seconds
CORONARYARTERY BYPASS GRAFTING
• the introduction of saphenous vein graft replacement for the severely
occluded coronary arteries

3. PHARMACOTHERAPY OF STABLE ANGINA
Antithrombotic drugs
• One of the major complications arising from atheromatous plaque is
thrombus formation. This causes an increase in plaque size and may result
in myocardial infarction.
Aspirin
• Aspirin acts via irreversible inhibition of platelet COX-1 and thus
thromboxane production, which is normally complete with chronic dosing
of 75 mg/day.
• This antiplatelet action is apparent within an hour of taking a dose of
300mg.
• The optimal maintenance dose seems to be 75–150 mg per day
• Dyspepsia is relatively common in patients taking aspirin and patients
should be advised to take the medicine with or immediately after food.
• Adverse reactions to aspirin include allergy, including bronchospasm.

4. Clopidogrel
• Clopidogrel inhibits ADP activation of platelets and is useful as an alternative
to aspirin in patients who are allergic or cannot tolerate aspirin.
• The usual dose is 300 mg once, then 75 mg daily.
• There is evidence that the combination of a proton pump inhibitor and
aspirin is as effective as using clopidogrel alone in patients with a history of
upper gastro- intestinal bleeding.
COX-2 inhibitors.
• The analgesic and anti-inflammatory action of non-steroidal anti-
inflammatory drugs (NSAIDs) is believed to depend mainly on their inhibition
of COX-2, and the unwanted gastro-intestinal effects of NSAIDs on their
inhibition of COX-1
• COX-2 inhibition reduces the production of prostacyclin, which has
vasodilatory and platelet- inhibiting effects.
• NSAIDs with high COX-2 specificity increase the risk of myocardial infarction
and should be avoided where possible in patients with stable angina.

5. ACE inhibitors
• In addition to the vasodilation caused by inhibiting the production of
angiotensin II, ACE inhibitors have anti-inflammatory, antithrombotic
and antiproliferative properties
• ACE inhibitors also reduce the production of ROS.
Statins
• Studies have repeatedly demonstrated the benefit of reducing cholesterol,
especially low-density lipoprotein-cholesterol (LDL-C), in patients with
CHD.
• In addition to cholesterol-lowering properties, statins also have
antithrombotic, anti-inflammatory and antiproliferative properties.
• They are also important in restoring normal endothelial function and
inhibit the production of ROS in the vessel wall.

6. SYMPTOM RELIEF AND PREVENTION
β-Blockers (first-line agents)
• They reduce myocardial oxygen demand by blocking β-adrenergic receptors,
thereby decreasing the heart rate and force of left ventricular contraction
and lowering blood pressure. The decreased heart rate not only reduces the
energy demand on the heart but also permits better perfusion of the
subendocardium by the coronary circulation.
• Patients treated optimally should have a resting heart rate of around 60
beats/min.
• β-Blockers should be used with caution in patients with diabetes.
• Cardioselective agents such as atenolol, bisoprolol and metoprolol are
preferred because of their reduced tendency to cause bronchoconstriction.
• β-Blockers should not be stopped abruptly for fear of precipitating angina
through rebound receptor hypersensitivity.
• They are contraindicated in the rare Prinzmetal‘s angina where coronary spasm
is a major factor.

7. Calcium channel blockers
• Longer acting dihydropyridines, for example, amlodipine and felodipine or
longer acting formulations, for example, nifedipine, have demonstrated
symptom-relieving potential similar to β-blockers.
• Dihydropyridines have no effect on the conducting tissues and are effective
arterial dilators, decreasing afterload and improving coronary perfusion
but also causing flushing, headaches and reflex tachycardia. This may be
overcome by combination with a β-blocker.
• CCBs with myocardial rate control as well as vasodilatory properties, for
example, diltiazem, and those with predominantly rate-controlling effects, for
example, verapamil, have also been shown to improve symptom control,
reduce the frequency of anginal attacks and increase exercise tolerance.
• CCBs have a particular role in the management of Prinzmetal's (variant) angina
which is thought to be due to coronary artery spasm.

8. Nitrates
• Organic nitrates are valuable in angina because they dilate veins and thereby
decrease preload, dilate arteries to a lesser extent thereby decreasing
afterload, and promote flow in coronary vessels.
• It relaxes vascular smooth muscle by releasing nitric oxide, which was
formerly known as endothelium-derived relaxing factor, which acts via cyclic
GMP.
• Tolerance is one of the main limitations to the use of nitrates. This develops
rapidly, and a ‘nitrate-free’ period of a few hours in each 24-h period is
beneficial in maintaining the effectiveness of treatment.
• Three main nitrates are used: Glyceryl Trinitrate (mainly for sublingual,
buccal, transdermal and intravenous routes), isosorbide dinitrate and
isosorbide mononitrate.

9. Nicorandil
• Nicorandil is a compound that exhibits the properties of a nitrate but which also
activates ATP-dependent potassium channels.
• Ranolazine has been shown to improve exercise time as monotherapy or in
combination with traditional antianginal agents.
Ivabradine
• Ivabradine represents a class of antianginal agents which block the If current. If
is a mixed Na+–K+ inward current activated by hyperpolarisation and
modulated by the autonomic nervous system. This regulates pacemaker
activity in the sinoatrial node and controls heart rate.
• Ivabradine is similar in efficacy to atenolol and CCBs and may be of particular
use in patients in whom β-blockers are contraindicated.
Ranolazine
• Ranolazine, a selective inhibitor of late sodium influx, attenuates the
abnormalities of ventricular repolarisation and contractility associated with
ischemia.
• It has been shown to increase exercise tolerance, reduce anginal episodes
and reduce the use of GTN.
• Side effects include dizziness, constipation, nausea, and the potential for
prolongation of the QTc interval.

11. • All patients should be treated for acute attacks and maintained on prophylactic
treatment for 6 to 12 months following the initial episode.
• Nitrates have been the mainstay of therapy for the acute attacks of variant angina
and coronary artery spasm for many years. Most patients respond rapidly to
sublingual nitroglycerin or isosorbide dinitrate
• Because calcium antagonists may be more effective, have few serious adverse
effects in effective doses, and can be given less frequently than nitrates, some
clinicians consider them the agents of choice for variant angina.
• Nifedipine, verapamil, and diltiazem are all equally effective as single agents for
the initial management of variant angina and coronary artery spasm
• β-Adrenergic blockade has little or no role in the management of variant angina
PHARMACOTHERAPY OF PRINZMETAL ANGINA