Intravenous Ibuprofen/Caldolor for Post-Electroconvulsive Therapy Myalgia

IV ibuprofen (trade name Caldolor) is a novel therapeutic modality approved by the US Food and Drug Administration (FDA) in June 2009 for the treatment of mild to moderate pain, as an adjunct to opioid analgesics, and for the reduction of fever. Ibuprofen is a non-steroidal anti-inflammatory drug (NSAID), which produces its effect through inhibition of the enzyme cyclooxygenase (COX). There are at least 2 variations of cyclooxygenase (COX-1 and COX-2) and ibuprofen non-selectively inhibits both, thus decreasing prostaglandin synthesis. This action gives ibuprofen its analgesic, anti-pyretic, and anti-inflammatory properties. NSAIDs have an established history of efficacy in the treatment of both acute and chronic somatic pain. Caldolor, being an intravenous formulation, offers a distinct advantage in patients who either are unable to take medications orally or are fasting preoperatively.

Post-procedure myalgia is a well-known and common complication of ECT. Although the exact etiology is unknown, the myalgias are believed to result from a combination of succinylcholine administration and the seizure activity induced by the ECT procedure itself. Succinylcholine-induced postoperative myalgias are a well-known phenomenon, initially described in the early 1950's. The exact pathogenesis is unknown, with muscle damage from succinylcholine-induced fasciculations or calcium-mediated phospholipase A2 activation and prostaglandin production being proposed as possible etiologies. The latter mechanism provides the rationale for using NSAID therapy. However, succinylcholine is unlikely to be the only factor involved in the development of myalgias following ECT, as a recent study showed that dose adjustments to succinylcholine did not affect rates of myalgia in these patients. Furthermore, seizures can also cause direct muscle injury and there have been reports of muscle pain after ECT both with and without succinylcholine.

A thorough literature search using Medline, Ovid, and scholar.google failed to find any research articles evaluating pretreatment therapy for myalgias in post-ECT patients. The current practice for the treatment of myalgias following ECT has been extrapolated from research on succinylcholine-induced myalgia in post-surgical patients. Previous studies have shown at least partial efficacy with pretreatment of nondepolarizing neuromuscular blocking agents, benzodiazepines, sodium channel blockers (predominantly lidocaine), and nonsteroidal anti-inflammatory drugs. The nature of the ECT procedure itself makes several of these modalities undesirable. Both Lidocaine and benzodiazepines can alter the seizure threshold and the short duration of the procedure possibly increases the risks associated with longer acting nondepolarizing muscle relaxants (ie. blurred vision, diplopia, difficulty breathing and swallowing). Therefore, the options for pretreatment are limited. In addition, a recent meta-analysis of randomized trials determined NSAIDs to cumulatively have the best efficacy of any pretreatment therapy in the prevention of post-procedural myalgias. Due to its intravenous formulation, some practitioners have administered ketorolac to ECT patients before the procedure. However, despite a proven efficacy in myalgia prevention shown by NSAIDs as a class, a study specifically examining the use of ketorolac in this regard failed to show any benefit. The use of Ibuprofen has yet to be examined.

Myalgias are a serious concern of patients and occur in approximately 50% of these cases. The pain is usually described as muscle soreness, similar to that resulting from strenuous exercise. The myalgias typically begin shortly after the procedure, lasting approximately 2-7 days in total. A recent study reported that 89% of patients considered prevention significant and would be willing to pay a median of $33 out of pocket to avoid this side effect. In addition to patient discomfort, myalgias can have a further financial burden if these patients are unable to return to work or resume previous daily activities in the days following the procedure. An agent that could treat and possibly even prevent these myalgias has the potential to be very beneficial to these patients.

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