• Bone fractures • Anticholinergic effects due to muscarinic receptor blockage, including dry mouth, blurred vision, constipation, urinary retention, confusion, and delirium • Antihistaminic effects due to histamine receptor blockage, including sedation, increased appetite causing weight gain, confusion and delirium Topical Lidocaine Data supporting the use of topical lidocaine is limited, though it is used frequently in the treatment of chronic pain. It is considered an adjuvant agent in the treatment of neuropathic pain, with the best evidence supporting its use in postherpetic neuralgia and diabetic neuropathy. 129 Lidocaine 5% patches are commonly used; a single patch contains 700mg of lidocaine. Up to three patches can be applied at a time for up to 12 hours in a 24-hour period; a 12-hour patch- free period is required each day due to the risk of lidocaine toxicity. Systemic absorption with lidocaine patches is low, averaging 3%, but this requires cautious use in patients with renal, hepatic, or cardiac dysfunction. 129 Pharmacologic Treatment of Pain: Opioids Historically, prescribers limited the use of opioids solely to patients with acute or cancer-related pain. Over time, the use of opioids to treat many types of pain has increased to dangerously high levels. Prescription rates of opioids had been steadily rising since the advent of new opioid products in the 1990s, and prescription rates peaked in 2012 with more than 255 million prescriptions for opioids written that year. Opioid prescribing rates have been slowly declining since 2012, with approximately 142 million opioid prescriptions written in 2020. 138 Declines in opioid prescribing are likely attributed to regulatory restrictions, more stringent clinical practice guidelines, education, and reimbursement controls. However, the opioid epidemic is a major public health crisis that is affecting Americans at alarming rates. 29 According to a report from the Substance Abuse and Mental Health Services Administration (SAMHSA), approximately 9.5 million people misused opioids in 2020. Of those users, 9.3 million participated in the recreational use of prescription painkillers. 139 An estimated 70,000 Americans died from opioid overdose in 2019. 138 • Sexual dysfunction • Diaphoresis • Tremor Patient-provider agreements Agreements between the patient and provider define the roles and responsibilities of the provider and patient when starting opioid therapy. They are used as a means to educate the patient on best practices for opioid use and can serve as a tool to identify concerns as the patient continues utilizing opioid therapy.
Components of an effective patient-provider agreement include 140 : • The provider and patient’s roles and responsibilities are clearly defined • Requirements that the patient will use one physician for prescribing and one pharmacy to fill prescriptions • Requirements for the use of both opioid and non-opioid pain medications • The patient’s consent to discuss care with other providers found in the state’s Prescription Drug Monitoring Program • An agreement that the patient will take their medication as prescribed and that refills will not be provided early • Definitions of the patient’s responsibilities in terms of keeping their medication safe and maintaining their supply • Appointment and drug screening requirements • Requirements for reporting side effects to the provider • A plan for what will happen if the benefits of therapy no longer outweigh the risks • Potential situations where opioids need to be tapered or discontinued for patient safety • Naloxone training for family and caregivers • A plan for referral to a specialized provider for opioid use disorder if the patient breaks the agreement or the provider has concerns about the patient developing substance use issues To be effective, the specifics of treatment must be characterized and explained using a tailored approach for the individual patient and their family or caregiver. This may require agreements to be provided in multiple languages. Agreements should be written at the sixth- to seventh-grade education level, or lower. Translators may be required for speakers of other languages to ensure patient understanding and effective informed consent. A patient who does not fully understand the potential risks and benefits of a treatment cannot be truly “informed” as required by the legal and ethical guidelines for medical practice. Time must be allowed for patients to ask questions, and for prescribers to ensure patients understand what they are being told. It is critical to ensure that none of the language used could be interpreted as coercive. 140,141 Patient-provider agreements are widely used, and come highly recommended for long-term opioid therapy, but their effects on preventing opioid misuse are not clear. A 2021 study found that although 66% of providers thought patient- provider agreements were worth the effort, only 28% considered them effective in decreasing opioid misuse. Despite their minimal effectiveness, providers still perceive these agreements as a valuable tool to use when prescribing opioids. 141 Informed consent The choice to start therapy with controlled substances should be a shared decision between the patient and the prescriber.
A discussion of benefits and risks should take place and documenting this discussion through written informed consent paperwork helps to ensure all aspects of the patient’s therapy are adequately addressed. Informed consent is a fundamental part of planning for any treatment, but it is critically important in long-term opioid therapy, given the potential risks of such therapy. Informed consent also fosters an open dialogue between the provider and patient, and may help protect the provider and clinic from any legal disagreements. 142 The Indian Health Service recommends that informed consent documents for opiate therapy should typically address the following concerns 142 : • The possible risks and benefits of opiate therapy. • Possible short-term and long-term side effects of opiate therapy such as cognitive impairment, constipation, overdose, and death. • The risk of developing tolerance and physical dependence. • The risk of oversedation and drug interactions, including drug-disease interactions such as the higher risk of using opiates in patients with sleep apnea or obesity. • The risk of impairing motor skills that can affect driving and other tasks. • The risk of misuse, dependence, opioid use disorder, and overdose. • The fact that there is little evidence of the benefits of long-term opiate use. • An agreement for the release of information to coordinate care with other treating providers. Pharmacology of Opioids Opioid receptors are found throughout the body, such as in the gastrointestinal tract, pituitary gland, skin, and immune cells, where they carry out various analgesic and non-analgesic functions. Opioids are classified by their effects at the opioid receptors, where they can be agonists, antagonists, partial agonists, or even a combination. An agonist such as morphine activates the receptor, whereas an antagonist such as naloxone blocks the receptor, resulting in no response and preventing agonists from binding to that receptor. Partial agonists such as buprenorphine and tramadol bind to receptors and can provide similar effects to full agonists at low dosages, but when the dosage increases, analgesic activity plateaus, so increased dosages do not increase analgesia but can increase side effects. In addition, some opioids, such as nalbuphine and butorphanol, demonstrate mixed activity that varies based on which opioid receptor is involved and also depending on the dose. 118,143,144 Each individual’s opioid-receptor makeup is unique, which results in significant variability in analgesia, side effects, and tolerance. Additionally, different opioid formulations and analogs have varying properties that affect absorption and pharmacokinetics. For example, fentanyl and its analogs are highly lipophilic, meaning they are fat- soluble. As a result, the onset of action is faster than less lipophilic drugs like morphine. 118,143,144
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