Profound hypotension following intravenous codeine phosphate. Three case reports and some recommendations

Narcotic Use for Acute Postoperative Pain Management in Mohs Micrographic Surgery Patients With End Stage Renal Disease: A Review of the Literature

BACKGROUND

Uncontrolled acute postoperative pain presents a significant management challenge when opioids are used in patients with end-stage renal disease (ESRD). Currently, there is a lack of quality pharmacokinetic and pharmacodynamic data regarding opioid medication use in ESRD patients to optimize safe and effective management.

OBJECTIVE

To review the published literature on pharmacologic evidence for and against the use of opioid medications for acute postoperative pain following Mohs micrographic surgery in ESRD patients.

METHODS

A search of PubMed was conducted to identify articles on the pharmacokinetic and pharmacodynamic properties of opioid pain medications in ESRD patients through March 1, 2020.

RESULTS

Seventy-five articles were reviewed. Limited data exist on opioids safe for use in ESRD and are mostly confined to small case series. Studies suggest tramadol and hydromorphone could be considered when indicated. Methadone may be a safe option, but should be reserved for treatment coordinated by a trained pain subspecialist.

CONCLUSION

Randomized clinical trials are lacking. Studies that are available are not sufficient to perform a quantitative methodologic approach. Evidence supports the judicious use of postoperative opioid medications in ESRD patients at the lowest possible dose to achieve clinically meaningful improvement in pain and function.

Toxicities of opioid analgesics: respiratory depression, histamine release, hemodynamic changes, hypersensitivity, serotonin toxicity

Opioid-induced respiratory depression is potentially life-threatening and often regarded as the main hazard of opioid use. Main cause of death is cardiorespiratory arrest with hypoxia and hypercapnia. Respiratory depression is mediated by opioid μ receptors expressed on respiratory neurons in the CNS. Studies on the major sites in the brainstem mediating respiratory rate suppression, the pre-Bӧtzinger complex and parabrachial complex (including the Kӧlliker Fuse nucleus), have yielded conflicting findings and interpretations but recent investigations involving deletion of μ receptors from neurons have led to greater consensus. Some opioid analgesic drugs are histamine releasers. The range of clinical effects of released histamine include increased cardiac output due to an increase in heart rate, increased force of myocardial contraction, and a dilatatory effect on small blood vessels leading to flushing, decreased vascular resistance and hypotension. Resultant hemodynamic changes do not necessarily relate directly to the concentration of histamine in plasma due to a range of variables including functional differences between mast cells and histamine-induced anaphylactoid reactions may occur less often than commonly believed. Opioid-induced histamine release rarely if ever provokes bronchospasm and histamine released by opioids in normal doses does not lead to anaphylactoid reactions or result in IgE-mediated reactions in normal patients. Hypersensitivities to opioids, mainly some skin reactions and occasional type I hypersensitivities, chiefly anaphylaxis and urticaria, are uncommon. Hypersensitivities to morphine, codeine, heroin, methadone, meperidine, fentanyl, remifentanil, buprenorphine, tramadol, and dextromethorphan are summarized. In 2016, the FDA issued a Drug Safety Communication concerning the association of opioids with serotonin syndrome, a toxicity associated with raised intra-synaptic concentrations of serotonin in the CNS, inhibition of serotonin reuptake, and activation of 5-HT receptors. Opioids may provoke serotonin toxicity especially if administered in conjunction with other serotonergic medications. The increasing use of opioid analgesics and widespread prescribing of antidepressants and psychiatric medicines, indicates the likelihood of an increased incidence of serotonin toxicity in opioid-treated patients.

Pore blocking: An innovative formulation strategy for the design of alcohol resistant multi-particulate dosage forms

In this work calcium stearate (CaSt) multi-particulates loaded with codeine phosphate (COP) were developed in an attempt to provide extended release (ER) combined with alcohol dose dumping (ADD) resistance. The pellets were prepared via wet/extrusion spheronization and ER characteristics were obtained after fluid bed drying at 30°C. Pore blockers (i.e., xanthan, guar gum and TiO2) were integrated to control the uptake of ethanolic media, the CaSt swelling and consequently, the COP release. While all three pore blockers are insoluble in ethanol, xanthan dissolves, guar gum swells and TiO2 does not interact with water. The incorporation of 10 and 15% TiO2 still provided ER characteristics and yielded ADD resistance in up to 40v% ethanol. The in-vitro data were subjected to PK simulations, which revealed similar codeine plasma levels when the medication is used concomitantly with alcoholic beverages. Taken together the in-vitro and in-silico results demonstrate that the incorporation of appropriate pore blockers presents a promising strategy to provide ADD resistance of multi-particulate systems.

Treatment of Pain in Pediatric Patients

A growing body of evidence demonstrates that untreated pain is associated with adverse consequences that can compromise clinical and developmental outcomes in children but that these adverse consequences can be prevented or attenuated by appropriate analgesic therapy. Thus, effective treatment of acute pain must be a clinical priority for children of all ages. Over the past 20 years, extensive pediatric research exploring pain assessment, developmental pharmacology of analgesics, and the clinical use of analgesics has dispelled many myths and misconceptions about pain management in pediatric patients; proven that analgesics can be used safely in neonates, infants, and children; and provided a framework for the development of pediatric pain management guidelines. This article reviews guidelines recommended for managing acute pain in pediatric patients and the treatment options for children experiencing acute pain. Contemporary issues regarding acetaminophen, nonsteroidal anti-inflammatory agents, and opioids are discussed.

A review of the efficacy and safety of opioid analgesics post-craniotomy*

--Codeine phosphate is the most commonly used analgesic post-craniotomy. --It is argued, in this paper, that codeine phosphate is an unpredictable pro-drug that does not equate to a safe and effective method of providing analgesia post-craniotomy. --Lack of evidence supporting tramadol's usage and concerns over its interactions and side effects mean its use cannot be advocated. --The traditional justification for withholding morphine in post-craniotomy pain appears to be largely based on anecdotal evidence. --Raising awareness among critical care nurses of the pharmacological properties of the analgesics used is imperative, if post-craniotomy pain is to be adequately treated. --There is an explicit challenge to the neurosurgical community to re-evaluate their pain-management strategies in the post-craniotomy patient.

A comparison of rectal and intramuscular codeine phosphate in children following neurosurgery

Codeine is frequently used for postoperative analgesia in children. Intramuscular injections are not ideal and the rectal route may be preferable. We compared rectal and intramuscular codeine administered following neurosurgery. 20 children (over 3 months) undergoing elective neurosurgical procedures, were randomized to receive either rectal or intramuscular codeine phospate (1 mg.kg-1) at the end of the procedure. Serum levels of codeine and morphine were assayed at intervals following administration (0, 30, 60, 120, 240 min). Fentanyl was the intraoperative analgesic and postoperative rescue analgesia was paracetamol, diclofenac and intramuscular codeine. The Children's Hospital of Eastern Ontario Pain Scale was used to assess analgesia. Peak codeine levels in both groups were observed at 30 min and morphine levels were consistently low. The plasma codeine levels were significantly greater at 30 and 60 min following intramuscular injection, and were associated with slightly better analgesia scores, but did not reach statistical significance. However, the peak plasma level occurred at similar times in both groups. Codeine is absorbed as rapidly via the rectal route compared with the intramuscular route but the peak levels are lower.

Pain following craniotomy: a preliminary study comparing PCA morphine with intramuscular codeine phosphate

We have performed a prospective randomised trial of 30 patients undergoing craniotomy to compare intramuscular codeine phosphate with patient-controlled analgesia using morphine 1 mg bolus with a 10-min lockout and no background infusion. For 24 h postoperatively, pain, nausea, Glasgow coma score, respiratory rate and sedation score were assessed. There was a wide variation in the amounts of morphine requested by the patients in the patient-controlled analgesia group in the first 24 h postoperatively (range 2-79 mg, median 17 mg). There was a small, but non-significant, reduction in pain scores in the patient-controlled analgesia group. There were no significant differences between the two groups in respect of nausea and vomiting, sedation score or respiratory rate. No major adverse effects were noted in either group. Patient-controlled analgesia with morphine is an alternative to intramuscular codeine phosphate in neurosurgical patients which merits further investigation.

Pharmacokinetics of opioids in renal dysfunction

Patients with renal insufficiency commonly require the administration of an opioid analgesic to provide adequate pain relief. The handling of morphine, pethidine (meperidine) and dextropropoxyphene in patients with renal insufficiency is complicated by the potential accumulation of metabolites. While morphine itself remains largely unaffected by renal failure, accumulation, as denoted by an increase in both mean peak concentrations and the area under the concentration-time curve, of both the active metabolite (morphine-6-glucuronide) and the principal metabolite (morphine-3-glucuronide, thought to possess opiate antagonist properties) have been reported. The increased elimination half-lives of the toxic metabolites norpethidine and norpropoxyphene in patients with poor renal function administered pethidine and dextropropoxyphene, respectively, makes their routine use ill advised. Case reports of prolonged narcosis associated with the use of both codeine and dihydrocodeine in patients with renal insufficiency call for care to be used when prescribing these agents under such conditions. Although the pharmacokinetics of buprenorphine, alfentanil, sufentanil and remifentanil change little in patients with renal failure, the continuous administration of fentanyl can lead to prolonged sedation.

A double-blind comparison of codeine and morphine for postoperative analgesia following intracranial surgery

Codeine and morphine were compared in a double-blind study of postoperative analgesia in 40 patients after intracranial neurosurgery. Eighteen patients received codeine phosphate 60 mg and 18 morphine sulphate 10 mg, both by intramuscular injection; 4 patients (10%) required no analgesia. Both drugs provided analgesia within 20 min of injection but morphine was more effective than codeine beyond 60 min (p = 0.01). Fewer doses of morphine than codeine were required (p = 0.003). Nine patients requested one dose of morphine and 9 two doses. Seven patients required three doses of codeine and 1 patient required four doses. Neither drug caused respiratory depression, sedation, pupillary constriction or unwanted cardiovascular effects. We conclude that, in the doses used, morphine is a safe alternative to codeine for analgesia after neurosurgery and has a more persistent action.

Hypoxaemia and hypotension after intravenous codeine phosphate

This report describes a case of accidental intravenous administration of codeine phosphate (1 mg.kg-1) to a previously healthy five-year-old boy, who was undergoing strabismus surgery. Hypoxaemia (SpO2 85% with FIO2 of 1) and hypotension (systolic BP 65 mmHg) resulted, which responded to resuscitation with lactated Ringers' (20 ml.kg-1) and phenylephrine (2 micrograms.kg-1). The degree of hypoxaemia observed in this case was severe, but was not associated with clinical evidence of bronchospasm. Possible mechanisms for this reaction might have included direct myocardial depression and histamine release. This case adds further support to the recommendation that codeine phosphate should never be administered intravenously.