Economic implications of potential drug–drug interactions in chronic pain patients

Abstract

Chronic pain patients may be subject to polypharmacy because of long-term pharmacological pain treatment and additional comorbidities. Many chronic pain patients expose themselves to potential drug–drug interactions (DDIs) and these interactions can have unintended and severe consequences. Prevalence and costs associated with DDIs are inconsistent and has led to an inadequate level of awareness among the medical community; therefore, it has become necessary to re-evaluate the rates of DDIs in chronic pain patients. Utilizing medical and prescription claims databases, five studies were conducted to assess the health care utilization of and associated financial payments for patients >18 years with chronic noncancer pain. The studies evaluated drug–drug exposures with the potential to cause DDIs specifically occurring through the CYP450 enzyme system. The studies reported that drug–drug exposures are prevalent, costly and can occur in any age group and that physicians should consider ways to limit their patients’ exposure to potential DDIs.

Keywords::

• chronic pain
• CYP450
• drug–drug exposure
• drug–drug interaction
• elderly
• opioids
• polypharmacy

Financial & competing interests disclosure

R Taylor and JV Pergolizzi are consultants for NEMA Rsearch Inc. JV Pergolizzi has acted as an advisory board member and consultant for both research and speaker programs for Endo Pharmaceuticals Inc. RA Puenpatom is an employee of Endo Pharmaceuticals Inc. K Summers, at the time of manuscript preparation, was an employee of Endo Pharmaceuticals Inc. This research was supported by Endo Pharmaceuticals Inc., Malvern, PA, which also funded scientific writing and editorial support. This manuscript has been reviewed and approved by Endo Pharmaceuticals (US/RD/PAIN/2012/00065a – approved on 23 September 2013).

Key issues

• • People with chronic low back pain and osteoarthritis (OA) are prevalent in the USA.

• • The majority of chronic noncancer opioid users such as low back pain and OA patients are presented with multiple morbidities resulting in exposure to many prescription medications to treat underlying diseases.

• • A pharmacokinetic drug-drug interaction has been defined as two or more drugs interacting in such a way that the effectiveness and/or toxicity of one or more of those agents are affected.

• • Drug-drug exposure (DDE) is defined as the risk of experiencing a drug–drug interaction in the presence of two or more administered medications.

• • Polypharmacy in chronic pain patients is not age dependent.

• • Patients who experienced DDEs utilized more health care resources than patients without DDEs.

• • When all age groups were compared in the OA and chronic low back pain populations, prevalence rates were rather similar, indicating that DDEs can affect anyone taking multiple medications regardless of age.

• • The treatment of chronic pain patients requires prescribers to know and consider the other concomitant medications received from other physicians. This may involve actively soliciting the patient for information about all drugs and over-the-counter products.

Notes