Aspirin plays a critical role in preventing serious complications after heart attacks and stent placements. It’s a core component of dual antiplatelet therapy (DAPT), usually paired with medications like clopidogrel or ticagrelor. However, around 2.5% of the population is hypersensitive to aspirin, creating a dilemma: how to protect these patients from blood clots without the most effective drug available?
Aspirin hypersensitivity can take many forms — from mild rashes and nasal congestion to life-threatening anaphylaxis or severe asthma attacks. These reactions may be pharmacological, caused by a shift in inflammatory pathways, or immunological, triggered by the body’s immune response. Despite its risks, no alternative to aspirin has been proven equally effective in the critical period following percutaneous coronary intervention (PCI) or myocardial infarction (MI).
That’s where aspirin desensitization comes in. This process involves gradually introducing small doses of aspirin under medical supervision until the patient can tolerate a full therapeutic dose. Studies show it’s highly successful, with success rates exceeding 95%. The process is typically completed within a day and is considered safe for most patients, barring rare, severe allergic conditions.
One of the most exciting enablers of this approach is the introduction of 3D-printed aspirin micro-tablets. Traditional tablet sizes (e.g. 75 mg) are too large for early-stage desensitization, which often starts with just 1 mg. The new system uses a 3D printer loaded with a medicinal ink, to which the active ingredient — in this case, aspirin — is precisely added. A disposable syringe dispenses the ink in accurate, weight-controlled doses, verified by an integrated scale. The pharmacy can now produce chewable tablets in exact doses of 1 mg, 5 mg, or 10 mg, making tailored desensitization both safer and more effective. This innovation allows medical teams to follow complex protocols with precision, reducing risk and improving outcomes.
The benefits of desensitization aren’t just theoretical. Case studies show real-life success: a 77-year-old woman with a history of skin reactions and a 56-year-old man with asthma and prior heart attacks, both underwent desensitization and were able to continue aspirin therapy without issue. These stories underscore how impactful and necessary this approach can be.
While some studies suggest that ticagrelor or prasugrel monotherapy might be used when desensitization isn’t possible, the evidence remains limited. Clopidogrel monotherapy is not recommended immediately post-PCI due to insufficient protection against clotting. Short-term intravenous alternatives exist but aren’t viable for long-term use.
Dosing also matters. The ideal maintenance dose of aspirin after desensitization is between 75 and 100 mg per day. Higher doses may be needed in rare cases, but they come with an increased bleeding risk. There’s also some evidence that body weight could influence optimal dosing, though this isn’t yet a basis for changing standard practice in secondary prevention.
In summary, aspirin desensitization offers a safe, effective, and increasingly accessible way to ensure patients with hypersensitivity can still receive the gold-standard treatment after cardiac events. As the field continues to innovate — particularly with customized dosing solutions through 3D printing — more patients will be able to benefit from this life-saving approach.
This blog article is based on the following publication: "Aspiriini ülitundlikkus ja desensibiliseerimine südame isheemiatõvega patsientidel" by Silver Kotter, Merilin Reimann, and Jana Lass.
The English version is available here.