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Chapter 28: Guidelines for Postoperative Medical Care of the Neurosurgical Patient 247

in some reports up to three times more than dogs that do not Alternative or Adjunctive Analgesics
receive corticosteroids [12]. Another major concern with the use of There is a variety of alternative or adjunctive analgesics that have
corticosteroids in dogs with IVD disease is gastrointestinal hemor- been used in both veterinary and human patients. In some cases
rhage. Dogs with IVD have been shown to be predisposed to gastro- there is limited scientific literature on the efficacy of these medica-
intestinal ulceration, and in a randomized study looking at high tions in veterinary medicine and their use has been translated from
doses of methylprednisolone sodium succinate, all dogs that the human literature. In most cases their use is associated with
received the steroid had evidence of gastric hemorrhage on endos- minimal adverse effects and may provide adjunctive or alternative
copy, whereas those in the control group did not [13]. Rare but fatal therapy for surgical patients, particularly if the use of corticoster-
colonic perforation has also been reported in dogs receiving dexa- oids precludes the use of NSAIDs.
methasone for IVD herniation with or without surgery [14,15].
Whether they are effective or not, gastroprotectants should be used Codeine
in patients that receive corticosteroids. Corticosteroids can also Oral codeine is an alternative analgesic for patients that cannot
lead to increased metabolic requirement, nitrogen losses, and receive NSAIDs or for patients that do not respond well to
hyperglycemia [16]. tramadol. Codeine is an opiate with 60% oral absorption in
Corticosteroids are often used for intracranial disease including dogs. Codeine is less potent than morphine. The dose of codeine
neoplasia and inflammatory conditions. In neoplasia it often for analgesia in dogs and cats is 0.5–2 mg/kg orally every 6–12
improves preoperative clinical status, which is thought to be due to hours [20].
a reduction in peritumoral edema. Vasogenic edema occurs sec-
ondary to the compressive effects of the tumor and responds well to Tramadol
antiinflammatory doses of corticosteroids [17]. Whether to con- Tramadol is a synthetic analgesic with weak μ‐opioid receptor
tinue with steroids postoperatively, what doses to use, and for how agonist effects that also inhibits the reuptake of serotonin and
long are typically personal preferences with no strict guidelines or norepinephrine. Tramadol has good oral absorption (around
clinical controlled studies published. Doses of steroids used for 65%) with a potency between that of codeine and morphine. Side
vasogenic edema in intracranial disease are typically antiinflamma- effects of tramadol are often related to the use of adjunctive drugs
tory: dexamethasone 0.25 mg/kg every 24 hours or prednisone that increase serotonin levels. Dosages reported in dogs are
0.25–0.5 mg/kg every 12–24 hours. 4–10 mg/kg orally every 6 hours and in cats 1–2 mg/kg every 12
hours [20].
NSAIDs Gabapentin
NSAIDs are widely used in both human and veterinary medicine Gabapentin is a γ‐aminobutyric acid (GABA) analog that has been
to provide analgesia. As understanding of the biological effects of shown to have some success in treating chronic pain, in particular
prostaglandins evolves, there has been development of drugs neuropathic pain [21]. Gabapentin also has some anticonvulsant
more selective for cyclooxygenase (COX)‐2 in an attempt to limit activity [22]. Oral antacids should not be administered with gabap-
the adverse effects such as gastrointestinal ulceration while entin as it may decrease its bioavailability. Analgesic doses used in
providing adequate antiinflammatory and analgesic effects. dogs and cats vary, with recommended doses of 5–10 mg/kg every
There are several NSAIDs that are currently approved for short‐ 8–12 hours. In cats, treatment should start at the lower dose and
and longer‐term use in dogs including carprofen, deracoxib, gradually increase if no adverse effects are noted within 2 hours
etodolac, firocoxib, meloxicam, and tepoxalin. The most com- [20]. Adverse effects that can be seen with administration of gabap-
mon adverse event reported in conjunction with the use of entin include sedation and ataxia, which are usually self‐limiting.
NSAIDs in dogs is gastrointestinal upset manifesting as vomiting
and diarrhea. NSAIDs should also be used with caution in Amantadine
patients with bleeding disorders, renal insufficiency, hepatic Amantadine is an antiviral drug that has NMDA receptor antago-
disease, or inflammatory bowel disease. Other adverse events nistic properties. It has recently been purported to be useful as an
that have been reported with the use of NSAIDs include adjunctive therapy for chronic pain [23]. The pharmacokinetics of
idiopathic hepatic failure (carprofen), especially in Labrador amantadine have not been described in dogs or cats and it therefore
Retrievers. In feline patients, the long‐term use of NSAIDs has should be used with caution in patients with renal or hepatic insuf-
not been approved by the Food and Drug Administration (FDA). ficiency. It is often used in addition to NSAIDs, which reportedly
Carprofen is approved as a single dose perioperatively (USA), improves its efficacy [23]. Doses reported for use in both dogs and
meloxicam as a single injectable dose (USA and Canada) followed cats are 2–5 mg/kg orally once daily, although 3 mg/kg is most com-
by 3 days of oral dosing (Canada), and more recently robenacoxib mon in cats [20]. Long‐term use and its side effects are unknown in
for up to 3 days (USA). Longer‐term use of meloxicam has been dogs and cats. Adverse effects are generally related to the gastroin-
reported in cats in Europe [18]. As the labeled dosing schedule testinal tract, but some patients may exhibit agitation.
for NSAIDs in cats varies for each region, the reader is referred
to the drug monographs when considering dose rates and Methocarbamol
intervals. Methocarbamol is a centrally acting muscle relaxant approved for
The duration of postoperative pain management is typically lim- use in acute inflammatory and traumatic injuries to the skeletal
ited to 5–7 days. If spinal hyperesthesia persists beyond this time, muscle and to reduce muscle spasms. The mechanism of action is
repeat imaging of the patient is recommended as residual disc unknown and its use in managing spinal patients for muscle pain
material or further disc extrusion may have occurred [19]. Other and to assist bladder expression is anecdotal with little evidence to
complications such as surgical site infection and discospondylitis suggest efficacy in either the human or veterinary literature [24,25].
may also need to be considered. Doses that have been reported for muscle relaxation in dogs are