The Insight Corner Hub: Palliative care: Pain Management

Treatment Guidelines on Pain Pharmacological options
Category	Drug Name	Potency	Potential Side effects	Cautions
1. Non-opioids	Acetaminophen	It should be the first step of the treatment if the pain level is mild. It may also be considered a good medication to add to an opioid treatment.	Hepatic toxicity. Light-headedness, sedation, constipation, dizziness, nausea, vomiting, respiratory depression	severe liver failure. Lower dose to 2 gms in liver disease.
	NSAIDs: The options which are considered as the safest nowadays are ibuprofen and naproxen.	May have a benefit in pain mediated by inflammation (e.g., bone metastases, musculoskeletal or skin pain) through the blockage of prostaglandins biosynthesis	Gastrointestinal irritation, bleeding	Renal failure
2. Weak Opioids	Codeine	converted to its active agents (among them morphine) through the enzyme CYP2D6. 10 mg codeine usually equivalent to 1 mg of morphine.	Ultra-rapid metabolizers and may have an increased risk of side effects. Sedation, nausea, vomiting, dizziness, constipation, CNS depression, sweating, headache, lethargy, confusion, light-headedness.	The only indication for codeine remains its action against cough, probably through its pro-drug.
	Tramadol	synthetic opioid, about five times less potent than morphine. Not considered to be "at risk" for addiction due its weak action on the mu opioid receptors.Due to its blockage of serotonin and norepinephrine reuptake, may have an additional benefit in neuropathic pain.	There are several limitations: a ceiling dose of 400 mg/day, an increased risk of seizures in predisposed patients, and more adverse effects than other opioids such as nausea and vomiting, especially in the geriatric population.
3. Strong Opioids	Morphine	Remains the “gold standard” as it has been the most extensively studied.	Lead to opioid-related toxicity. Sedation, hypotension, increased sweating, constipation, dizziness, drowsiness, nausea, vomiting, dry mouth, somnolence, respiratory depression.	Renal impairment
	Hydrocodone	slightly less potent than morphine. Unfortunately, it is only available in combination with APAP or NSAIDs. It is metabolized to hydromorphone.	Sedation, hypotension, increased sweating, constipation, dizziness, drowsiness, nausea, vomiting, dry mouth, somnolence, respiratory depression.
	Hydromorphone	similar properties than morphine but around five times more potent	Lead to neurotoxicity at high doses	Renal impairment
	Oxycodone	synthetic opioid. Unfortunately not available as parenteral formulation. Slightly more potent than morphine (10 mg morphine=7.5 mg oxycodone). Targets not only mu receptors as other usual opioids but also kappa receptors, which explains why it may have a better action on neuropathic pain and may produce less nausea and vomiting.	Light-headedness, sedation, constipation, dizziness, nausea, vomiting, sweating, respiratory depression	Kidney, Renal impairment
	Oxymorphone	semisynthetic. Twice as potent as morphine
	Fentanyl	Highly lipid soluble opioid which can be administered parenterally, transdermally, transmucosally, buccally, intranasally but not orally. Extremely potent (around 100 times morphine)	Sedation, sweating, headache, vertigo, lethargy, confusion, light-headedness, nausea, vomiting, respiratory depression.
	Meperidine	Analgesic, preoperative, medication, support of anesthesia	Not recommended because of the neurotoxic effects of its metabolites (increased risk of seizures in predisposed population) and its high risks of addiction.
	Methadone	synthetic opioid. Poor reputation due to the variability in half-life for individuals requiring careful titration and optimal compliance (half-life prolonged with prolonged use).	Light-headedness, dizziness, sedation, nausea, vomiting, constipation, respiratory depression
4. Coanalgesics or adjuvant analgesics	Antidepressants: desiprimine and nortriptyline are better tolerated,  antiepileptic and drugsanticonvulsants: gabapentin and pregabalin for neuropathic pain