CVS: nitrates, statins

Question 1

Indications of nitrates?

E.g. isosorbide mononitrate, glyceryl trinitrate

Answer 1

Acute angina (glyceryl trinitrate -short acting)

Prophylaxis of angina (isosorbide mononitrate -long acting)

Pulmonary oedema

Question 2

Mechanism of action of nitrates?

Answer 2

Nitrates are converted into nitric oxide (NO).

NO increases cyclic guanosine monophosphate (cGMP) synthesis and reduces intracellular Ca2+ in vascular smooth muscle cells, causing them to relax. This results in vasodilation.

Relaxation of the venous capacitance vessels reduces cardiac preload and left ventricular filling. These reduce cardiac work and myocardial oxygen demand, relieving angina and cardiac failure.

Nitrates can relieve coronary vasospasm and dilate collateral vessels, improving coronary perfusion.

Question 3

Adverse effects of nitrates?

Answer 3

Flushing
Headaches
Light-headedness
Hypotension

Question 4

Warnings of nitrates?

Answer 4

Contraindicated in severe aortic stenosis.

Avoid in pts who are haemodynamically unstable, particularly hypotension.

Question 5

Interactions of nitrates?

Answer 5

Do not prescribe along side PDEi (phosphodiesterase inhibitors; e.g. sildenafil) -prolongs hypotensive effects.

Caution if pt is taking antihypertensive meds.

Question 6

Monitoring of nitrates?

Answer 6

Efficacy
- improvement of symptoms

Monitor
- BP (if IV transfusion; infusion rate adjusted to ensure the systolic BP is not <90mmHg)

Question 7

Pt education on nitrates?

Answer 7

Aims to relieve chest pain/SOB.

May develop headache initially but will go away.

Take GTN spray prior to activities that may trigger angina.

Sit for 5mins before taking GTN spray and sit for another 5mins after taking the med -risk of postural hypotension.

Question 8

Indications of statins?

Answer 8

Primary prevention of CVS events e.g. MI, stroke.

Secondary prevention to prevent cardiovascular events, first line alongside lifestyle changes.

Primary hyperlipidaemia
- primary hypercholesterolaemia
- mixed dyslipidaemia
- familial hypercholesterolaemia.

Question 9

MOA of statins?

Answer 9

Statins reduce serum cholesterol levels by inhibiting 3-hydroxy-3-methyl-glutaryl coenzyme A (HMG CoA) reductase, which is usually involved in making cholesterol.

• This decreases cholesterol production by the liver and reduces low density lipoprotein (LDL) cholesterol in the blood.

Statins indirectly reduce triglycerides and high density lipoprotein (HDL) cholesterol levels, which slow the atherosclerotic process and may reverse it.

Question 10

Adverse effects of statins?

Answer 10

• Headache
• GI disturbances
• Muscle aches
• Myopathy
• Rhabdomyolysis
• Rise in liver enzymes (ALT)

Question 11

Warnings of statins?

Answer 11

Avoid in:
- pregnant
- breastfeeding

Caution in:
- hepatic impairment

Reduce dose in renal impairment.

Question 12

Interactions of statins?

Answer 12

Metabolism reduced by CYP450 inhibitors.
- leads to accumulation of statin in body and increase SEs.

Question 13

Monitoring of statins?

Answer 13

Primary prevention:
- check lipid profile before tx and 3 months after starting tx.
- aim for 40% reduction in non-HDL level

Secondary prevention:
- check for cholesterol level improvement -efficacy
- check liver enzymes (ALT) before tx, 3months and 12 months after starting tx. -safety (if ALT rise >3x above upper limit then stop statin. Once liver enzyme is normal, restart statin at lower dose.
- check creatine kinase if pt reports muscle symptoms.

Question 14

Pt education of statins?

Answer 14

Aims to lower cholesterol levels to reduce the risk of heart attack or stroke in the future.

Seek medical attention if experiencing muscle symptoms.

Tell pt to return at 3 and 12 months for blood tests.

Keep alcohol to minimum.

Avoid grapefruit juice if taking simvastatin or atorvastatin because the body will find it difficult to breakdown statin and increase risk of side effects.