Myoclonus and urinary retention following subarachnoid morphine injection in a dog

Myoclonus and hyperalgesia following intended epidural morphine administration in a dog

“…It is more commonly seen following chronic exposure, but has been reported in humans and animals following single high doses (Angst and Clark 2006). Myoclonus, brief, shock-like contractions of a muscle or group of muscles, is less common but has been reported following intrathecal administration of preservative-free morphine in dogs at normal doses (Kona-Boun and others 2003, Iff and others 2012) and following inadvertent overdose (Da Cunha and others 2007). Myoclonus with hyperalgesia has been reported in humans receiving chronic pain management with repeated large doses of intrathecal morphine (Krames and others 1985, De Conno and others 1991).…”

“…Naloxone has been shown to be ineffective in a number of cases (Werz and MacDonald 1982, Da Cuhna and others 2007), which is possibly because the neuroexcitatory effects of morphine are not opioid receptor medicated (Werz and MacDonald 1982). A number of other medications have been used in existing case reports involving dogs and include intravenous phenobarbitone, pentobarbitone, atracurium, acepromazine and butorphanol with varying degrees of success (Kona-Boun and others 2003, Da Cuhna and others 2007, Iff and others 2012). …”

Comparison of analgesia provided by lidocaine, lidocaine-morphine or lidocaine-tramadol delivered epidurally in dogs following orchiectomy

“…Such adverse reactions have been seen when morphine was administered intramuscularly or intravenously (Valadão et al 2002). Kona-Boun et al (2003) reported a case of myoclonus followed by urinary retention in a dog after intrathecal injection of morphine. Urinary retention can occur due to the relaxing effect of morphine on the detrusor muscle of the bladder (Pascoe & Dyson 1993).…”

An Update on Drugs Used for Lumbosacral Epidural Anesthesia and Analgesia in Dogs

“…The use of a 5-hydroxytryptamine antagonists (e.g., ondansetron) has been described as treatment for neuraxial opioid-induced pruritus (102). Myoclonic activity upon recovery from anesthesia was also reported following intrathecal administration of morphine in dogs (15, 100) but this is not a clinical issue with epidural injections, providing that the maximum dose of 0.1 mg kg −1 is respected and accidental puncture of the subarachnoid space does not take place during needle insertion (103). Studies showed that approximately 3% of dogs receiving epidural morphine showed urinary retention postoperatively (6, 104).…”

“…In this case, abnormal urinary patterns were observed in up to 39% of canine individuals (105). In practice, gentle bladder expression after surgery and before patient extubation avoids atony of the detrusor muscle and urinary retention (15). …”