**6.8 Calcitonin**

*Pain Management - Practices, Novel Therapies and Bioactives*

pain and this can be exploited to amputees as well [3, 9, 10].

**6.4 Acetaminophen**

**6.5 NSAIDs**

**6.6 Muscle relaxants**

neurotransmitter, but they are unable to bind to any GABA receptors. In addition to the use with seizures, it has been used for chronic pain, especially neuropathic in nature. Dosages must be titrated slowly, and results are not seen immediately. These doses also must be adjusted for patients with impaired renal function with the help of a pharmacist [25, 26]. However, some studies claim that its efficacy to treat phantom limb pain is inconclusive and limited by dose dependent side effects like somnolence and dizziness [2]. There are other studies more recently that show promise of administration of gabapentinoids for reducing chronic post-surgical

Acetaminophen's exact mechanism of action is not well understood, but it is thought to reduce the production of prostaglandins in the brain. Prostaglandins are chemicals that cause inflammation and swelling. Acetaminophen relieves pain by elevating the pain threshold, that is, by requiring a greater amount of pain to develop before a person feels it. Acetaminophen administration to amputation patients will help with inflammation and an adjunct to help with post-surgical nociceptive pain, which has been shown to decrease opioid requirements.

Acetaminophen dosages will be lowered in patients with pre-existing liver disease [27]. This will be the most beneficial in the early pre-operative phase. It may be especially beneficially to start prior to the amputation as part of a pre-emptive analgesia. This is thought to protect the central nervous system from noxious insults

NSAIDs work by inhibiting the activity of cyclooxygenase enzymes (COX-1 or COX-2). By blocking the Cox enzymes, many prostaglandins are not made. This means that there is less swelling and less pain. Most NSAIDs block both Cox-1 and Cox-2 enzymes. For pain, this specifically looks at enzymes that work with prostaglandins for inflammation. Like acetaminophen, these medications work well in the acute perioperative phase for nociceptive pain and reducing opioid requirements. Their use can be limited due to post-operative bleeding concerns. Usually these medications do not help with chronic post amputation pain or phantom limb pain. A short course may be suitable for some patients that have normal renal function; however, we do not advocate for chronic NSAID therapy due to the risks of gastroin-

As discussed earlier, acute post-operative pain can have spasmodic pain proximal to the stump site, likely due to tissue inflammation. This can also be present with residual limb pain in some patients. There are a variety of muscle relaxants that can be tried for a short period of time [30]. If the patient is on opioids, would be cautious of adding a benzodiazepine for muscle relaxant. There is a lack of adequate

literature supporting the use of muscle relaxants for post amputation pain.

**6.7 Tri-cyclic antidepressants and selective norepinephrine reuptake inhibitors**

Anti-depressants are commonly prescribed for chronic neuropathic pain and coexisting depression that accompanies it. These medications work by inhibiting serotonin-epinephrine uptake blockade, NMDA receptor antagonism and sodium

which result in the patient getting hyperalgesia and allodynia [10, 28].

testinal bleeding and renal toxicity [10, 23, 29].

**40**

Calcitonin is a hormone secreted by thyroid gland in parafollicular cells. Unlike the parathyroid hormone, its job is to reduce calcium in the blood. There are synthetic forms of this used for chronic pain syndromes. The exact pain mechanism of action is unknown. There are mixed results of phantom limb pain [10]. The greatest benefit has been shown when it is administered early in the perioperative period; usually within the first 7 days [32]. There are reports of complete resolution of phantom limb pain with its use [9].
