Effect of Roux-en-Y gastric bypass on the pharmacokinetic-pharmacodynamic relationships of liquid and controlled-release formulations of oxycodone

Analgesic medication considerations for chronic pain management post-bariatric surgery

INTRODUCTION

Bariatric surgery, an option for obesity management, can significantly alter gastrointestinal structure and processes. These changes can impact the pharmacokinetics (PK) of medications which can translate to clinical differences in efficacy and safety. Chronic pain is prevalent in obesity and often persists post-bariatric surgery.

AREAS COVERED

This narrative review examines the PubMed literature from 1990 to January 2024 for the impact of bariatric surgery on the management of chronic pain medications including non-opioid (acetaminophen, non-steroidal anti-inflammatory drugs, antidepressants, and cannabinoids) and opioid medications.

EXPERT OPINION

An individualized medication management approach is ideal for post-bariatric surgery patients, as PK parameters, type of surgery, time since surgery, and patient specific factors make it difficult to support blanket recommendations. Close monitoring of efficacy and safety outcomes is essential in chronic pain management. While the PK of acetaminophen and opioids are impacted, the value of these medications in the setting of chronic pain is dwindling as more efficacy and safety data emerges. A life-long ban of NSAIDs due to marginal ulcer risk is not endorsed; rather, we advocate for shifting the focus to marginal ulcer prevention strategies, individualized benefit-risk analysis, and safety monitoring using surrogate markers.

Management of Pain Medication in Patients With a History of Bariatric Surgery: A Systematic Review

CONTEXT

Obesity prevalence is persistently increasing worldwide. Among surgical therapeutic procedures, bypass surgery and sleeve gastrectomy have shown the best results regarding weight loss, prevention, and treatment of secondary complications. However, these surgeries are associated with an increased risk of malabsorption and metabolic changes that could further affect the pharmacokinetics of drugs. On the other hand, patients with a history of such surgeries are more likely to experience pain and request analgesic initiation or adaptation. The question of how to manage pain medication in these patients is challenging due to their narrow therapeutic indexes.

OBJECTIVES

To summarize the current literature on the impact of bariatric surgery on the subsequent pharmacokinetics of analgesics and propose a multidisciplinary therapeutic attitude to optimize pain management in these patients.

METHODS

We conducted a systematic review that included all pharmacological studies published after 2000.

RESULTS

Unexpectedly, these surgeries seem to increase the bioavailability of drugs by long-term improvement of hepatic function. Yet, the medical community drastically lacks robust guidelines for pain management in those patients. This systematic review aims to bring together pharmacological studies related to the use of pain treatments in patients who underwent bypass surgery or sleeve gastrectomy.

CONCLUSIONS

Caution should be exercised regarding the risk of overdose in every circumstance: treatment initiation, change of doses, or change of molecule. More prospective trials comparing the pharmacokinetics of medications in obese patients with and without prior bariatric surgery are needed.

Opioid Analgesics after Bariatric Surgery: A Scoping Review to Evaluate Physiological Risk Factors for Opioid-Related Harm

The persisting use of opioids following bariatric surgery has emerged as a prevalent complication, heightening the probability of opioid-related harm (ORM), such as opioid-related fatalities and prescription opioid use disorder (OUD). A comprehensive review of PubMed literature from 1990 to 2023 was conducted to pinpoint physiological influences on postoperative ORM. As a result, we found that patients undertaking bariatric operations often exhibit an inherently higher risk for substance use disorders, likely attributable to genetic predisposition and related neurobiological changes that engender obesity and addiction-like tendencies. Furthermore, chronic pain is a common post-bariatric surgery complaint, and the surgical type impacts opioid needs, with increased long-term opioid use after surgeries. Additionally, the subjective nature of pain perception in patients with obesity can distort pain reporting and the corresponding opioid prescription both before and after surgery. Furthermore, the postoperative alterations to the gastrointestinal structure can affect the microbiome and opioid absorption rates, resulting in fluctuating systemic exposure to orally ingested opioids. The prospect of ORM development post-bariatric surgery appears amplified due to a preexisting susceptibility to addictive habits, surgically induced pain, modified gut-brain interaction and pain management and the changed pharmacokinetics post-surgery. Further research is warranted to clarify these potential risk variables for ORM, specifically OUD, in the bariatric population.