Safety Precautions for Minitran (Nitroglycerin) Plaster During MRI
Minitran plasters should be removed before an MRI procedure due to the risk of burns from the conductive materials in the patch when exposed to radiofrequency fields during scanning. 1
Risks Associated with Transdermal Medications During MRI
- Transdermal medication patches like Minitran may contain conductive materials (such as metal backing or components) that can heat up during MRI scanning, potentially causing severe and rapid burns 1
- Radiofrequency (RF) fields used in MRI can create localized heating when in contact with any conductive material left on the patient's skin 1
- The MRI's powerful radio transmitter interacts with patient tissue and any conductive materials at the resonant frequency of the scanner, leading to power dissipation and temperature increase 1
Required Safety Protocol
- All patients must be thoroughly screened for devices, implants, and medication patches before entering the MRI environment 1
- Minitran plasters should be removed and the skin area cleaned before the MRI procedure 1
- The removal should be documented as part of the MRI safety screening process 1
- After the MRI is completed, a new Minitran plaster can be applied according to the original prescription schedule 1
MRI Safety Classification System
All equipment and implants for MRI use fall into three formal categories 1:
- MR Safe: contains no material that would present a hazard at any field
- MR Conditional: safe to scan under specified conditions detailed by the manufacturer
- MR Unsafe: presents an unacceptable risk to patients or staff if used within the MR environment
Transdermal medication patches with conductive components are typically considered MR Unsafe due to the risk of RF heating 1
Additional Safety Considerations
- All staff and patients must be screened for ferromagnetic materials before entering the MRI suite 1
- Special MRI-compatible monitoring equipment must be used if the patient requires monitoring during the procedure 1
- Careful documentation of the removal and subsequent reapplication of the Minitran plaster should be maintained to ensure continuity of treatment 1
- The MRI department's MR Responsible Person and MR Safety Expert should be consulted regarding any questions about medication patches and MRI safety 1
Clinical Implications
- Temporary discontinuation of nitroglycerin delivery during the MRI procedure is generally well-tolerated for most patients 1
- For patients with unstable angina or those highly dependent on continuous nitroglycerin therapy, the timing of the MRI should be carefully planned, and alternative short-acting nitroglycerin formulations should be available if needed 1
- The clinical team should weigh the risks of temporary discontinuation against the risks of potential thermal injury 1