As a hospitalist who practices in a perioperative clinic, I probably spend more of my time with patients reviewing and discussing the medications they are taking than on any other single subject. Surgical patients—many of whom are elderly—commonly are on multiple medications, have renal or hepatic disease that can alter drug metabolism, and may not be adequately educated about their medication regimens.
Patient safety is the overriding concern behind perioperative medication management, consistent with the medication-related objectives in the Joint Commission’s 2009 National Patient Safety Goals.1 The increasing surgical burden that comes with an aging population, along with rising expectations for functional recovery, has likewise elevated the importance of perioperative medication management.
Despite these demands, there is scant evidence from randomized controlled trials to directly guide perioperative medication management. For this reason, recommendations in this area rely largely on other forms of evidence, including expert consensus, case reports, in vitro studies, recommendations from pharmaceutical companies, and other known data (pharmacokinetics, drug interactions with anesthetic agents, and effects of the agent on the primary disease and on perioperative risk).
This article reviews general principles of perioperative medication management and then presents four case vignettes to explore perioperative recommendations for a number of common medication classes. It is not intended as a comprehensive review of the perioperative management of all medications, as numerous classes (antiplatelets, beta-blockers, oral hypogycemic agents, insulin, statins) are discussed in detail elsewhere in this proceedings supplement.
GENERAL CONSIDERATIONS IN MEDICATION MANAGEMENT
A comprehensive medication history is fundamental
Effective perioperative management of medications requires an understanding of the patient and his or her comorbidities so that the risk of perioperative decompensation can be gauged. This understanding stems from a thorough medical history that includes a comprehensive medication history to provide a complete inventory of the following:
- All prescription medications
- All over-the-counter (OTC) agents (including nonsteroidal anti-inflammatory drugs [NSAIDs])
- All vitamins
- All herbal medications.
When to stop, when to resume?
Guidance on stopping and resuming medications in the perioperative period is relatively absent from the literature. General considerations include the following:
- The potential for withdrawal when stopping a medication
- The progression of disease with interruption of drug therapy
- The potential for interactions with anesthetic agents if the medication is continued.
Abrupt discontinuation of some drugs may lead to unnecessary complications due to the potential for withdrawal. Common medications that have been associated with withdrawal symptoms are selective serotonin reuptake inhibitors (SSRIs), beta-blockers, clonidine, statins, and corticosteroids.2 A recent systematic literature review concluded that continuation of chronic corticosteroid therapy without supplemental (stress) doses of corticosteroids is appropriate unless patients have primary disease of the hypothalamic-pituitary-adrenal axis, in which case perioperative stress dosing is recommended to avoid acute adrenal insufficiency (addisonian crisis).3
Patients on chronic drugs are more likely to have complications
In a medication survey of 1,025 patients admitted to a general surgery unit, Kennedy et al reported that 49% of the patients were taking medications (other than vitamins) unrelated to their surgical procedure.4 Even while this percentage is considerably lower than what I observe in my practice, this study showed that medication use has important perioperative consequences4:
- The odds ratio for a postoperative complication was 2.7 (95% CI, 1.76–4.04) if patients were taking a drug unrelated to their surgery.
- The risk of a complication was particularly elevated if patients were taking cardiovascular drugs or agents that act on the central nervous system; if patients were on NPO (“nothing by mouth”) orders for more than 24 hours before surgery; and if the operation was more than 1 hour in duration. These findings could reflect destabilization of the disease processes for which the patients were taking chronic medications that required interruption.
Unintended discontinuation of chronic drugs
Stopping a chronic medication for a surgical procedure raises the possibility that its resumption could be overlooked, especially since medical errors are particularly common in the transition between health care settings following hospital discharge. A population-based cohort study among all elderly patients discharged from Ontario, Canada, hospitals over a 5½-year period found that 11.4% of patients undergoing elective surgery did not resume their indicated chronic warfarin therapy within 6 months after its presurgical discontinuation.5 Although 6-month rates of unintended failure to resume therapy were lower for statins (4%) and ophthalmic beta-blocker drops (8%),5 these findings underscore that drug discontinuation always carries a risk that therapy might not be resumed as indicated.
Stress response to surgery. Decisions about perioperative drug therapy should always take into account the stress response to surgery and the challenge it presents to homeostasis in the face of increased sympathetic tone and release of pituitary hormones.
Unreliable absorption of oral medications. Surgery and the postoperative state can lead to unreliable absorption of oral drugs for any of a number of reasons: villous atrophy, diminished blood flow to the gut, edema, mucosal ischemia, diminished motility from postoperative ileus, and use of narcotics.6
Take-away general principles
The following principles can be applied to guide perioperative medication management in a general sense7:
- Continue medications with withdrawal potential
- Discontinue medications that increase surgical risk and are not essential for short-term quality of life
- Use clinical judgment when neither of the above two principles applies, but be mindful that many other medications are given in the narrow perioperative time window and that metabolism and elimination of chronic drugs may be altered.