Can a Patient Alternate Between Voltaren (Diclofenac) and Aspercream (Trolamine Salicylate)?
No, patients should not routinely alternate between Voltaren (diclofenac) and Aspercream (trolamine salicylate) due to increased risk of gastrointestinal toxicity and bleeding complications from combining NSAIDs with salicylates, with little to no increase in efficacy. 1
Primary Safety Concern: Combining NSAIDs with Salicylates
Concomitant use of diclofenac with salicylates (including topical formulations like trolamine salicylate in Aspercream) increases the risk of GI toxicity without providing additional therapeutic benefit. 1
The FDA drug label for diclofenac explicitly states that "the concomitant use of diclofenac with other NSAIDs or salicylates is not recommended." 1
Even when aspirin is combined with diclofenac, there is a pharmacokinetic interaction where aspirin markedly reduces the bioavailability of diclofenac, potentially decreasing its effectiveness. 2
Mechanism of Increased Risk
Both diclofenac and salicylates inhibit prostaglandin synthesis through cyclooxygenase inhibition, leading to additive gastrointestinal mucosal damage. 3
Diclofenac increases platelet aggregation time, and when combined with salicylates (which also affect platelet function), the bleeding risk is compounded. 2
Clinical trial data combining oral NSAIDs with topical diclofenac showed higher rates of rectal hemorrhage (3% vs. <1%) and more frequent abnormal laboratory values compared to single-agent therapy. 1
Safer Alternative Approaches
If Using Topical Diclofenac (Voltaren Gel):
Use diclofenac gel alone at the recommended dose of 1% gel applied to affected areas 2-4 times daily without adding other topical or oral NSAIDs/salicylates. 4
Topical diclofenac provides effective local analgesia with limited systemic exposure and lower incidence of systemic adverse events compared to oral formulations. 4
If Additional Pain Relief is Needed:
Consider acetaminophen (up to 4g daily) as a first-line addition rather than alternating with another NSAID or salicylate. 3
For localized pain, compounded topical formulations containing combinations of amitriptyline-ketamine, clonidine, gabapentin, or lidocaine may be considered as alternatives that don't carry the same interaction risks. 3
Nonpharmacologic interventions including physical modalities should be incorporated for pain likely to be relieved with such approaches. 3
Critical Monitoring if Combination Cannot Be Avoided
If clinical circumstances absolutely require using both agents (which is strongly discouraged):
Conduct periodic laboratory evaluations including CBC, renal function (BUN, creatinine), liver function studies, and fecal occult blood testing every 3 months. 3, 1
Monitor closely for signs of gastrointestinal bleeding, including black tarry stools, hematemesis, or unexplained anemia. 3
Assess for worsening renal function, particularly in elderly patients, those on diuretics, or with pre-existing renal impairment. 1
Common Pitfalls to Avoid
Do not assume that using one agent topically and another orally eliminates interaction risks—systemic absorption still occurs with topical formulations. 1
Patients often self-medicate with over-the-counter topical salicylate products (like Aspercream) without informing providers they're using prescription topical diclofenac, creating inadvertent combination therapy. 3
The cumulative irritant effect of multiple topical agents can cause excessive dryness and local adverse effects even beyond systemic concerns. 3