Codeine | Prescribe for no more than 4 days in breastfeeding women: some women rapidly convert codeine to morphine, causing neonatal toxicity Overall lower risk of overdose and addiction than with stronger opioids |
Tramadol | Associated with seizures in patients at high risk of seizure or when combined with medications that increase serotonin levels (eg, SSRIs) Lower risk of overdose and addiction than with stronger opioids |
Morphine | A metabolite of morphine can accumulate to toxic levels in patients with renal impairment |
Oxycodone, hydromorphone | Use with caution for patients at higher risk of opioid misuse and addiction |
Fentanyl | Before prescribing fentanyl, ask about opioid use within the past 2 weeks; to ensure full tolerance, the patient should be taking a daily, scheduled dose of at least a 60- to 90-mg MED for at least 2 weeks, at least twice daily for CR opioids and at least 4 times daily for IR opioids Do not switch from codeine to fentanyl, regardless of the codeine dose; some patients have little or no opioid tolerance even with regular codeine use Maintain the initial dose for at least 6 days; use extra caution with patients at higher risk of overdose (eg, elderly patients, those taking benzodiazepines) Advise the patient as follows:
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Apply the patches as prescribed; do not apply more than 1 patch at a time -
Avoid heat sources such as heating pads -
Dispose of patches securely
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Methadone | Use methadone to treat pain only if you hold a written Health Canada exemption Titration is hazardous because of its very long half-life, which leads to bioaccumulation |
Meperidine | Not recommended for CNCP:
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Oral meperidine has poor bioavailability and is less effective than codeine -
Normeperidine, a toxic metabolite, can accumulate with frequent use of meperidine
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Acetaminophenopioid combinations | Use with caution to avoid acetaminophen toxicity: no more than 3.2 g of acetaminophen for adults, which is equal to 10 tablets a day for codeine-acetaminophen or oxycodone-acetaminophen combinations; no more than 8 tablets a day for tramadol-acetaminophen combinations Warn heavy drinkers to not mix alcohol use with acetaminophen |
CR formulations | Titrate with caution; CR tablets contain higher opioid doses than IR formulations do and can easily be converted to IR by biting or crushing the tablet |
Parenteral opioids | Not recommended for CNCP:
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