Clonidine is an alpha-2 agonist that has been in use as an orally administered pill since 1974 when it was FDA approved for treatment of hypertension. Clonidine was approved in 1996 for use via continuous epidural infusion with opiates for treatment of severe pain in cancer patients and is also approved for treatment of attention deficit hyperactivity disorder in pediatric patients and adults.
Several studies have demonstrated the ability of epidurally administered clonidine to produce an analgesic benefit in acute post-surgical pain across a variety of surgery types in adults (Nigam 2017, Rao 2017, Shaikh 2016) and in children (Walker 2012). Epidural clonidine demonstrated a beneficial effect in treating lumbosacral radiculopathy when added to a transforaminal epidural steroid injection (Tauheed 2014).
Epidural clonidine was recently evaluated as a monotherapy for sciatica patients in a randomized controlled trial versus triamcinolone (Burgher 2011). In this study, clonidine demonstrated significant improvement in pain score at 2 and 4 weeks relative to baseline without serious side effects or signs of hypotension.
In addition to analgesia, non-clinical and clinical evidence demonstrate that clonidine has potent anti-inflammatory effect by reducing pro-inflammatory cytokine expression in patients following total abdominal hysterectomy surgery (Kim 2000) and in animal models of acute sciatica nerve inflammation (Romero-Sandoval 2005).