Harms of opioids used in dentistry

Generally, when given in equianalgesic doses, opioids have a similar spectrum and incidence of adverse effects; however, there can be significant interpatient variability. Elderly or frail patients may be particularly sensitive to opioids, so require careful monitoring.

Harms associated with opioids include:

adverse effects—serious adverse effects (eg opioid-induced ventilatory impairment, accidental death) are more likely to occur when opioids are used in high doses or concomitantly with other sedative drugs (eg benzodiazepines, alcohol, cannabis). Adverse effects with short-term use of opioids lists adverse effects that can occur with short-term opioid use; for a more detailed discussion of the adverse effects of opioids, see here
aberrant behaviour (eg diversion, nonmedical use, abuse, addiction)—the risk of opioid abuse is high; in some studies, opioid abuse was reported in more than 20% of patients taking long-term opioids for chronic noncancer pain
risk of overdose—increased opioid prescribing rates have been associated with a significant increase in the number of fatalities involving opioids
neuroadaptive and physiological changes (eg opioid tolerance, opioid dependence, opioid-induced hyperalgesia)—may occur after 7 to 10 days of use.

Table 1. Adverse effects with short-term use of opioids
[NB1]
System	Adverse effects
respiratory	opioid-induced ventilatory impairment (excessive sedation with or without a decrease in respiratory rate [NB2]), which is more marked during sleep accidental death increased risk of sleep-disordered breathing (central or obstructive apnoea) cough suppression
neurological	delirium, sedation, dysphoria or euphoria, miosis, impaired cognition other adverse effects can occur in patients with renal impairment
cardiovascular	bradycardia, vasodilation and hypotension (including postural hypotension)—usually only seen after the use of large intravenous doses during anaesthesia or if the patient is hypovolaemic
dermatological	pruritus [NB3] widespread urticaria—suggests an allergic response
gastrointestinal	nausea, vomiting, constipation, spasm of the sphincter of Oddi
urinary	urinary retention and difficulty with micturition, increased external sphincter tone, decreased detrusor muscle tone
Note: NB1: For a more detailed discussion of the adverse effects of opioids, see here. NB2: A decrease in respiratory rate is an unreliable indicator of opioid-induced ventilatory impairment, which can coexist with a normal respiratory rate. Sedation is a more sensitive indicator of opioid-induced ventilatory impairment. NB3: Opioid-induced pruritus is not associated with a rash and is thought to be due to an action on opioid receptors.

Adverse effects can be limited by using the lowest dose for the shortest duration possible.

Provide appropriate verbal and written education to patients and their carers about the sedating effects of opioids, including:

not to drive or operate machinery
how to recognise the signs of excessive sedation (eg not being able to stay awake or be roused from sleep)
to seek medical attention if they become excessively sedated (because this can be an early indicator of ventilatory impairment) or experience other concerning adverse effects.

Note: Advise patients and their carers of the sedating effects of opioids.

Constipation is a frequent adverse effect of opioids—advise patients to obtain a stimulant laxative (eg docusate with senna) if it becomes an issue.