aspirin use in MI

[Pharmguru]

Does anyone know if Aspirin should be used in combination with clopidogrel or would this only benefit in patients undergoing PCI.

[Nik]

Both are recommended, clopidogrel at the higher (unlicensed) dose of 600mg if PCI is planned. Duration of use depends on number of factors, not least whether pt has had STEMI or NSTEMI

[Pharmguru]

But it is only recommeneded aspirin at a dose of 300mg is given in the ambulance...

Clopi would only be added in if PCI then?

[Nik]

No both are recommended at a stat dose of 300mg each, ideally before admission and continued during admission. Whether that's in the ambulance or at home doesn't make a difference, so long as the hospital are aware it has been given. Full details in the BNF.

[Pharmguru]

thanks for that, I hadn't noticed there was an intro section. I thought you would only use enxoparain or fondaparinaux in STEMI, the artery is only partially occluded in NSTEMI so what is the basis of this

[Nik]

the artery is only partially occluded in NSTEMI so what is the basis of this

The basic difference between STEMI and NSTEMI is the change seen on an ECG, hence ST elevation MI and non ST elevation MI. The underlying pathophysiology is due to rupture of atherosclerotic plaques that have built up in our coronary arteries, a consequence mainly due to our our lifestyle and diet in the West. Plaque rupture leads to platelet activation, hence the use of anti-platelets, with the risk of thromboembolism formation further down coronary arteries. Emboli formation can then lead to ischaemia and release of cardiac markers (troponins). Fondaparinux is associated with lower mortality at 6 months compared to enoxaparin with similar rates of ischaemic events in the short term, hence more hospitals use fondaparinux. Clinical textbooks and pharmacology texts will provide more info.

[Pharmguru]

Thank you for that, I have covered it now in clinical pharmacy and therapeutics. Have you seen a patient on a combo of nitrate tablets and the patch before? Just wondering whether there would be a potential problem of not being able to avoid nitrate free period.

[Nik]

Both m/r nitrates and patches are licensed for angina prophylaxis, so there shouldn't be a need to use both together. I haven't seen pt's on both. Patches can be removed at night if tolerance is a problem, and re-sited in the morning.

[Pharmguru]

NIK have you spotted that the BNF says tirofiban or eptifatide can be used with aspirin or unfractionated heparin. I am sure it can be used with LWMH or fondaparinux too?

Also long term management of NSTEMI has no reference to Beta blocker but I am sure people are supposed to be on them.

[Nik]

We use eptifibatide where I work only in high risk NSTEMI pt's i.e recurrent chest pain with ECG changes. The GP II/IIIa inhibitors are generally used when interventional procedures are planned such as PCI. Although I mentioned fondaparinux has been shown to be superior to enoxparin in ACS, for pt's undergoing PCI there is an increased risk of catheter thrombi being formed, so these pt's should be having enoxaparin instead.

Beta blockers should be started and continued post MI, see NICE guidance.