From the FDA Drug Label
Directions drink a full glass of water with each dose adults and children 12 years and over: take 4 to 8 tablets every 4 hours not to exceed 48 tablets in 24 hours unless directed by a doctor Active Ingredient (in each tablet) Aspirin 81 mg (NSAID)nonsterodial anti-inflammatory drug
The daily aspirin dose for a patient with fibromuscular dysplasia, bilateral renal arteries is 81 mg to 648 mg per day, as the label instructs to take 4 to 8 tablets every 4 hours, with each tablet containing 81 mg of aspirin 1, 1.
From the Research
For patients with fibromuscular dysplasia (FMD) affecting bilateral renal arteries, the recommended daily aspirin dose is 75-100 mg once daily. This low-dose aspirin regimen should be initiated at diagnosis and continued indefinitely unless contraindicated, as it helps prevent thrombotic complications, particularly in those with renal artery involvement where microthrombi can form at sites of arterial stenosis or aneurysms 2. Patients should take the aspirin with food to minimize gastrointestinal side effects. The low dose is sufficient to inhibit platelet aggregation while minimizing bleeding risks. Aspirin therapy should be temporarily discontinued 7-10 days before any planned invasive procedures to reduce bleeding risk. Patients with aspirin allergy may be prescribed alternative antiplatelet agents such as clopidogrel 75 mg daily.
Some key points to consider in the management of FMD include:
- Regular blood pressure monitoring is essential for these patients, as renal artery FMD commonly causes hypertension that may require additional management 3
- Invasive treatment, such as percutaneous transluminal renal angioplasty (PTRA), should be considered when hypertension cannot be controlled with antihypertensive drugs and in patients with impaired renal function or ischemic nephropathy 4
- Surgical revascularization may be indicated after PTRA complications, such as thrombosis, perforation, progressive dissection, repeated PTRA failure, or restenosis 5
- The disease involves the mid and distal renal arteries and branchpoints, posing endovascular treatment challenges that separate FMD from atherosclerotic disease 6
It's worth noting that while the provided studies offer valuable insights into the management of FMD, the most recent and highest quality study should be prioritized when making definitive recommendations. However, based on the available evidence, the recommended daily aspirin dose of 75-100 mg once daily remains a reasonable and evidence-based approach to preventing thrombotic complications in patients with FMD affecting bilateral renal arteries.