Is diclofenac (nonsteroidal anti-inflammatory drug (NSAID)) contraindicated before a radioiodine uptake test?

Diclofenac Use After Radioiodine Uptake Test

Diclofenac is not contraindicated after a radioiodine uptake test and can be safely used once the test is completed. 1

Relationship Between NSAIDs and Radioiodine Testing

• Radioiodine uptake tests measure thyroid function by assessing how much radioactive iodine is absorbed by the thyroid gland, primarily used in the evaluation of thyrotoxicosis and thyroid cancer 1
• There is no evidence in the guidelines that diclofenac or other NSAIDs interfere with radioiodine uptake after the test has been completed 1
• The primary concern with medications and radioiodine testing is interference before the test, not after 1

Medications That Do Interfere With Radioiodine Testing

• Medications that must be discontinued before radioiodine uptake testing include those that affect iodine uptake and retention 1
• Most interfering medications need to be withheld for 1-3 days prior to the test, with the exception of depot forms of antipsychotics which require a 1-month withdrawal period 1
• Specific medications that can interfere with radioiodine uptake include:
  • Nifedipine, which can cause prolonged retention of the tracer in the thyroid 1
  • Various drugs that affect iodine transport mechanisms 1

Considerations for Diclofenac Use

• While diclofenac has several contraindications and precautions, none relate to radioiodine uptake testing 1
• Diclofenac's primary contraindications are related to:
  • Cardiovascular risk (increased risk of thrombotic events) 1
  • Gastrointestinal risk (bleeding, ulceration) 1
  • Perioperative pain in coronary artery bypass graft surgery 1
  • Renal impairment 1

Clinical Recommendation

• After completion of a radioiodine uptake test, diclofenac can be safely administered if indicated for pain management 1
• When prescribing diclofenac after radioiodine testing, standard precautions for NSAID use should be followed:
  • Use the lowest effective dose for the shortest duration 1
  • Consider cardiovascular risk factors (diclofenac has a higher cardiovascular risk profile than naproxen) 1, 2
  • Consider gastrointestinal protection in high-risk patients 1
  • Avoid in patients with renal impairment 1

Conclusion

• There is no contraindication to using diclofenac after a radioiodine uptake test 1
• The timing of medication administration is only relevant before the test, not after 1
• Standard precautions for NSAID use should be followed when prescribing diclofenac for any indication 1