Calculation of equianalgesic dosages Follow these three steps to calculate equianalgesic dosages when changing to a different opioid analgesic: Step 1 : Calculate the total daily dose of the current opioid. Step 2 : Determine the equianalgesic dose using the appropriate conversion factor or ratio. Step 3 : Reduce the new opioid analgesic dose by 33% to 50% to account for cross-tolerance, dosing ratio variation, and patient variability. Determine a new regimen based on the available dosage form(s) of the new opioid. Clinical Case Example CD is a 32-year-old female with chronic pain. She is taking Exalgo 16 mg once daily and hydromorphone immediate- release 4 mg three times daily for breakthrough pain. The patient should be transitioned to MS Contin due to insurance issues. What dose of MS Contin should be started? Step 1: Calculate the total daily dose of the current opioid. Exalgo 16 mg once daily + hydromorphone immediate-release 4 mg three times daily = 28 mg/day hydromorphone Monitoring adults receiving chronic opioid therapy Ongoing patient monitoring and reiterating vital components of the agreed-upon treatment plan are necessary during long- term therapy with opioids. In addition, continue to assess patient-spe- cific improvement versus risks of opioid treatment to determine if changes or discontinuation of opioid therapy are required. Functional improvements may be incremental and occur over months or years. Further, some patients who begin showing sol- id progress may plateau. In these cases, consider reassessment. Functional goals and objective evidence of achievement include: ● Participate in physical therapy sessions: Documentation of progress from physical therapist. ● Sleeping in bed instead of chair: Reported by a caregiver, fam- ily member. ● Participation in a pain support group: Letter from the group leader. ● Ability to walk around the block: Self-report, pedometer, care- giver, friend . ● Return to work: Pay stubs, a letter from the employer. (HHS, 2019b) Clinicians must be vigilant for aberrant behaviors indicating a pa- tient may be at risk for misuse or abuse of opioids that could result in addiction and substance abuse disorder. A review of PDMP be- fore prescribing or renewing may indicate if the patient is seeing other providers unbeknownst to the primary prescriber. Discuss any unexpected results thoughtfully, as errors in data have been known to occur. Urine drug screening may determine if the pa-
Step 2: Determine the equianalgesic dose using the appropriate conversion factor or ratio. Oral hydromorphone to oral morphine conversion ratio: 4 28 mg hydromorphone/day × 4 = 112 mg morphine/day OR 28 mg hydromorphone equianalgesic dose of morphine 7.5 mg = 30 mg Equianalgesic dose of morphine/day = 112 mg Step 3: Reduce dose by 33% to 50% to account for cross- tolerance; determine a new regimen based on available dosage forms of the new opioid.
Total daily dose of morphine = 74 to 56 mg/day New regimen: MS Contin 30 mg every 12 hours (Total morphine dose = 60 mg/day)
NP Consideration: Opioid equianalgesic dose conversions are not the same as the MME conversions. Do not use MME factors to convert between opioid medications, as this may lead to serious adverse effects, including respiratory depression, overdose, and death. tient has ingested other medications or illicit substances beyond the agreed-to treatment plan. Urine screening tests may produce false positives. A qualitative test will confirm any positive result from a urine screening test. Review with patients the need for securely storing their opioid medications to prevent misuse by others and possible accidental exposure, especially to children and pets. When opioid treatment is discontinued, advise patients to return unused opioid medications to drug take-back programs sponsored by pharmacies, the DEA, or other local agencies. If these programs are unavailable, counsel patients to dispose of their medicines in the household trash by following these steps: 1. Remove drugs from their original containers and mix them with something undesirable, such as used coffee grounds, dirt, or cat litter. This makes the medicine less appealing to children and pets and unrecognizable to someone who might intentionally go through the trash looking for drugs. 2. Put the mixture in something that can be closed (e.g., a resealable plastic bag, empty can, or another container) to prevent the drug from leaking. 3. Throw the container in the garbage. 4. Delete personal information on empty prescription medication bottles or packaging to protect identity and privacy. Throw the packaging away. 5. Do not flush opioids down the toilet or drain, as this can contaminate the water supply. (Pino & Wakeman, 2022)
MANAGING OPIOID-INDUCED ADVERSE EFFECTS
An essential component of any chronic opioid therapy follow- up evaluation is assessment for opioid-related adverse effects. Tolerance to acute opioid-induced side effects (e.g., sedation, nausea/vomiting, itching) will develop; however, other adverse ef- fects may continue to be an issue. Additionally, clinicians must be aware of long-term side effects. Opioid-induced constipation is a risk throughout chronic opioid therapy. Therefore, prescribing scheduled use of stool softeners (e.g., docusate) and stimulants for those receiving chronic opioids is warranted. In addition, instruct patients to contact their pre- scriber if they do not have a bowel movement at least every 2 to 3 days to avoid developing impaction. In some cases, a prescription medication for opioid-induced constipation may be necessary.
Patients do not develop tolerance to the opioids’ respiratory de- pressive effects, even with chronic therapy. Additionally, this risk increases if other CNS depressant agents (prescribed or illicit) or alcohol are concurrent. Consider prescribing naloxone (Narcan), an opioid antagonist, for any patient at risk of opioid-induced respiratory depression. When administered to a patient experi- encing an opioid overdose and opioid-induced respiratory de- pression, naloxone can rapidly reverse all signs and symptoms of opioid intoxication. Many states have passed laws expanding ac- cess to naloxone, allowing pharmacists to dispense or distribute naloxone without a prescription under certain circumstances. As part of the FDA’s action plan regarding the safety of opioid analgesics, it has released several safety-related product labeling updates. In addition, the FDA (2018) updated warnings across the
EliteLearning.com/Pharmacy
Book Code: RPTX3024
Page 74
Powered by FlippingBook