Can a patient take Voltaren (Diclofenac) now after taking Relafen (Nabumetone) at 10 am?

Concurrent Use of Relafen and Voltaren: Safety Considerations

The patient should not take Voltaren (diclofenac) after taking Relafen (nabumetone) earlier in the day due to the increased risk of adverse effects from using multiple NSAIDs concurrently.

Rationale for Avoiding Concurrent NSAID Use

Relafen (nabumetone) and Voltaren (diclofenac) are both non-steroidal anti-inflammatory drugs (NSAIDs) that work through similar mechanisms:

• Both drugs inhibit cyclooxygenase (COX) enzymes, with nabumetone's active metabolite (6-MNA) and diclofenac both having preferential COX-2 inhibition 1
• Taking multiple NSAIDs concurrently increases the risk of adverse effects without providing additional therapeutic benefit 2

Specific Risks of Concurrent Use

1. Increased gastrointestinal toxicity

   • The FDA drug label explicitly states: "Concomitant use of diclofenac with other NSAIDs or salicylates increases the risk of GI toxicity, with little or no increase in efficacy" 2
   • Even topical diclofenac has been associated with gastrointestinal bleeding 3

2. Enhanced cardiovascular risks

   • Both medications carry cardiovascular risks that may be additive
   • The American Heart Association notes that all NSAIDs, regardless of COX-2 selectivity, carry cardiovascular risks 4
   • Diclofenac specifically has been associated with higher cardiovascular risk (RR 1.63) compared to some other NSAIDs 5

3. Potential pharmacokinetic interactions

   • Research has shown that nabumetone's active metabolite (6-MNA) can affect the protein binding of diclofenac 6
   • This interaction could potentially increase free diclofenac concentrations, enhancing both therapeutic and adverse effects

Recommended Approach

1. Wait at least 24 hours between doses of different NSAIDs

   • Nabumetone has a long half-life with its active metabolite (6-MNA) having a half-life of 22-30 hours 1
   • This means significant drug levels are still present many hours after dosing

2. Alternative pain management options if additional pain relief is needed today:

   • Acetaminophen (if not contraindicated)
   • Non-pharmacological approaches (ice, heat, rest)
   • Consult with healthcare provider about appropriate timing for switching between NSAIDs if needed

Important Monitoring Considerations

If the patient regularly requires multiple pain medications, their provider should:

• Assess for underlying causes requiring multiple analgesics
• Monitor renal function and blood pressure, as NSAIDs can lead to impaired renal perfusion and hypertension 4
• Watch for signs of GI toxicity (abdominal pain, dark stools)
• Consider cardiovascular risk factors before prescribing any NSAID regimen 5

Conclusion

The concomitant use of Relafen and Voltaren is not recommended due to increased risks without additional benefit. The patient should wait until tomorrow before taking Voltaren or consult their healthcare provider about alternative pain management strategies for today.