CC
A 30-year-old female presents to the office complaining that “the pain medication is making me feel nauseous.” (Nausea is one of the most commonly seen adverse effect of orally administered opioids. In a large retrospective review, it was found that female adults have a 60% higher risk of nausea and vomiting than male adults when administered opioids.)
HPI
The patient had several mandibular teeth extracted with no intraoperative complications 2 days before presentation. She was given a 3-day prescription for a combination analgesic containing hydrocodone (an opioid) and acetaminophen. She reports poor oral intake since her procedure and has been feeling nauseated, with one episode of vomiting since taking the medication. (Opioids have a greater tendency to cause nausea and vomiting when taken on an empty stomach.) She has not had any relief from pain and explains that she is now worse because she has both pain and nausea.
A detailed history of symptoms can provide clues to rule out other causes for this acute nausea episode. Abrupt onset of nausea and vomiting is suggestive of cholecystitis, food poisoning, gastroenteritis, pancreatitis, or drug-related etiologies. If a patient has pain, obstructive etiologies must be considered.
Postoperative nausea and vomiting (PONV), defined as nausea and vomiting occurring in the 0- to 24-hour postoperative period, is one of the most common complaints after surgery. It has a multifactorial etiology, and risk factors for the development of PONV have been identified ( Table 9.1 ). A simplified scoring system by Apfel and colleagues (1999) is one of the most popular and widely used scoring systems. They identified four highly predictive risk factors for PONV: Female gender, history of motion sickness or PONV, nonsmoker, and use of perioperative opioids. The presence of 0, 1, 2, 3, or 4 of these factors corresponded to a PONV incidence of 10%, 21%, 39%, 61%, and 79%, respectively.
| Patient Factors | Anesthetic Factors | Surgical Factors |
|---|---|---|
| Female | Use of perioperative opioids |
|
| Nonsmoker | Use of volatile anesthetics | Ear, nose, and throat |
|
Nitrous oxide |
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Risk factors for postdischarge nausea and vomiting, in which symptoms occur late (24–72 hours) appear to be similar to the typical risk factors for PONV and are also likely related to, among other factors, emetic symptoms before discharge, increased pain at home, and the use of postoperative opioids.
The term opioid is used to refer to all the agonists and antagonists of the morphine-like family of compounds. This term is preferred to older terms, such as opiate or narcotic . Narcotic refers to any drug that can cause dependence; the term is not specific for opioids (i.e., not all narcotics are opioids).
PMHX/PDHX/medications/allergies/SH/FH
The patient has no known history of narcotic abuse (a risk factor for drug-seeking behavior). Current medications include hydrocodone/acetaminophen (5/325 mg tablets). She admits to having ingested four tablets in the past 6 hours, with minimal oral intake.
Examination
General. The patient is a well-developed and well-nourished female who appears her stated age and is in mild discomfort secondary to nausea. (The physical examination of this patient should focus initially on signs of dehydration, evaluating skin turgor and mucous membranes and observing for hypotension or orthostatic changes.) She is alert and oriented to time, place, and person. (It is important to assess mental status in cases of acute opioid toxicity.)
Vital signs. Her vital signs are stable, and she is afebrile (AF), except for slight tachycardia at 110 bpm (caused by dehydration secondary to decreased oral intake).
Maxillofacial. Pupils are 3 mm, equal, round, and bilaterally reactive. (Pupillary constriction, or miosis, would be a sign of excessive opioid intake and is not affected by tolerance.)
Intraoral. The examination is consistent with healing extraction sockets with no evidence of alveolar osteitis or acute infection. Mucous membranes are moist and within normal limits.
Abdominal. The abdomen is soft, nontender, and nondistended; bowel sounds are present but hypoactive in all four quadrants. (Abdominal examination may not be routine in this situation, but it may demonstrate decreased bowel sounds secondary to the effect of opioids on gastrointestinal [GI] motility or distension with tenderness suggestive of a bowel obstruction. Pain in the right upper quadrant is more consistent with cholecystitis or biliary tract disease.)
Imaging
No imaging studies are indicated unless the situation is compounded by other medical conditions. For patients with a suspicion of aspiration, such as those with concomitant alcohol consumption or decreased mental status secondary to excessive opioid intake, chest radiography may be indicated.
Labs
No laboratory studies are indicated unless dictated by preexisting medical conditions, such as uncontrolled diabetes. In patients with prolonged vomiting, metabolic alkalosis and other electrolyte abnormalities may ensue. Appropriate laboratory studies should be ordered as needed.
Assessment
Acute nausea and vomiting associated with postoperative opioid analgesia, status post dentoalveolar surgery; subjective report of moderate pain that is nonresponsive to the current pharmacologic regimen.
It is important to distinguish acute pain, which is of recent onset and limited duration, from chronic pain, which is described as lasting for an undefined period, beyond that expected for the injury to heal. This distinction has both diagnostic and treatment implications. Caution should be exercised when treating chronic pain with opioids because of the development of dependence.
Treatment
Several different approaches can be used, either alone or in combination, for the management of the adverse effects of opioids. These include:
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Dose reduction of the systemic opioid
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Symptomatic management of the adverse effect
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Opioid rotation (or switching)
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Alternate routes of systemic administration
Reducing the dose of the administered opioid can result in a reduction of dose-related adverse effects. To compensate for the loss of pain control, adjunctive strategies can be used to maintain control while reducing the dose or eliminating the opioid. Common strategies include addition of a nonopioid coanalgesic or an adjuvant analgesic that is appropriate to the pain syndrome and mechanism (e.g., addition of gabapentin (Neurontin) for the treatment of neuropathic pain). In addition, therapy targeting the cause of the pain (e.g., placement of packing material into a dry socket wound), application of a regional anesthetic, or a neuroablative intervention may be used.
Symptomatic management of the adverse effect is usually based on cumulative anecdotal experiences. In general, this involves the addition of one or more new medications. However, polypharmacy adds to medication burden, and the possibility of drug interactions needs to be considered.
Opioid rotation (also called opioid switching or substitution ) requires familiarity with a range of opioid agonists and with the use of opioid dose conversion tables to find equianalgesic dosages. The objective of switching one opioid with another is to reduce the adverse effects. Alternatively, switching the route of systemic administration, such as changing from the intravenous to the oral route, has been shown to ameliorate symptoms of nausea, constipation, and drowsiness. In many acute situations, nonsteroidal antiinflammatory drugs (NSAIDs) provide analgesia equal to the starting doses of opioids. However, unlike opioids that lack a ceiling dose, NSAIDs have a maximum dose above which no additional analgesic effect is obtained.
The current patient was treated with a single dose of oral promethazine (Phenergan) 12.5 mg. (Studies have shown that 12.5 mg of oral Phenergan is as effective in reducing symptoms of nausea as 25 mg of oral Phenergan and may result in fewer adverse effects.) The patient’s medication was switched to a nonopioid analgesic (ibuprofen 400 mg orally every 6 hours). She was also instructed to increase her oral intake, preferably with isotonic drinks. She responded well to this regimen, with resolution of her nausea and reduction of pain to an acceptable level. If the initial antiemetic agent fails, a rescue antiemetic from a different treatment class can be considered.
Complications
Although opioids are well recognized as being effective for moderate to severe pain, they are frequently associated with an array of troublesome side effects ( Table 9.2 ). Genuine allergy to opioids is rare. In most cases, patients report having an opioid allergy when they actually have had an opioid-related adverse effect.
| Body System | Adverse Effects |
|---|---|
|
|
The following are some of the complications that can arise with opioid therapy.
Nausea and vomiting. Approximately 40% of patients using opioids report experiencing nausea and 15% to 25% of patients may experience vomiting after opioid administration. It is a common and unpleasant adverse effect of opioids. However, fewer than 20% of patients experiencing these side effects reported this to their health care providers. Opioid receptors play an important role in the control of emesis (vomiting). They directly stimulate the chemoreceptor trigger zone (CTZ), depressing the vomiting center and slowing GI motility. Signaling between the CTZ and the vomiting center is mediated through a variety of neurotransmitter receptor systems, including the serotonergic, dopaminergic, histaminergic, cholinergic, and neurokininergic receptors. The available antiemetics block one or more of the associated receptors ( Table 9.3 ). The 2014 Consensus Guidelines for the Management of Postoperative Nausea and Vomiting now recommend prophylactic antiemetics in moderate- to high-risk patients to reduce the risk of nausea and vomiting. There is no “universal” antiemetic, and no current single antiemetic is 100% effective for all patients.
