Major
Diclofenac × tacrolimus
Non-steroidal anti-inflammatory drugs (NSAIDs)×Calcineurin inhibitor (immunosuppressant)
Mechanism
Diclofenac (NSAID) suppresses renal prostaglandin synthesis maintaining glomerular perfusion. Tacrolimus is nephrotoxic in its own right. Additive acute kidney injury risk in transplant patients.
Symptoms
Reduced urine output, rising creatinine, potassium accumulation. In kidney transplant patients: accelerated graft function decline.
Management
Avoid chronic diclofenac on tacrolimus. For analgesia post-transplant, use paracetamol (up to 2 g/day) or a short opioid course. For neuropathic pain, gabapentin or pregabalin.