Methadone is a synthetic opioid with unique pharmacokinetic and pharmacodynamic properties that distinguish it from other commonly used opioids. Originally developed as an analgesic and later adopted for opioid use disorder (OUD) treatment, methadone’s duration of action plays a central role in both its therapeutic benefits and its risks. Understanding the distinction between its analgesic duration and elimination half-life is essential for safe and effective clinical use.
Methadone acts primarily as a μ-opioid receptor agonist but also exhibits N-methyl-D-aspartate (NMDA) receptor antagonism and inhibits serotonin and norepinephrine reuptake. These additional mechanisms contribute to its efficacy in chronic pain, neuropathic pain, and opioid tolerance. Clinically, methadone’s analgesic duration of action is relatively short, typically lasting 4 to 8 hours after a single dose. This duration is comparable to that of other short-acting opioids and explains why methadone, when used for pain management, often requires divided dosing throughout the day.
In contrast, methadone’s elimination half-life is prolonged and highly variable, ranging from approximately 8 hours to more than 50, with reports of even longer half-lives in some individuals. This disparity between analgesic duration and elimination half-life is one of methadone’s most clinically significant features. While analgesia may wane within hours, the drug continues to accumulate in tissues and plasma with repeated dosing. As a result, steady-state concentrations may not be achieved for several days, increasing the risk of delayed toxicity if doses are escalated too rapidly.
The prolonged and variable half-life of methadone is largely explained by its pharmacokinetics. Methadone is highly lipophilic, leading to extensive tissue distribution and slow release back into circulation. It is metabolized primarily by hepatic cytochrome P450 enzymes, including CYP3A4, CYP2B6, and CYP2D6, which exhibit significant interindividual variability. Genetic polymorphisms, drug–drug interactions, and hepatic function can therefore markedly influence methadone clearance and duration of action.
In the treatment of opioid use disorder, methadone’s long duration of action is therapeutically advantageous. Once-daily dosing suppresses opioid withdrawal symptoms and cravings for 24 hours or longer, while also attenuating the euphoric effects of shorter-acting opioids. This pharmacologic profile supports treatment adherence and reduces illicit opioid use. However, the same properties necessitate careful induction and titration, particularly during the first one to two weeks of therapy, when accumulation can lead to oversedation or respiratory depression.
Methadone’s extended duration of action also has important safety implications. Respiratory depression may occur late after dosing, especially during initiation or dose increases. Additionally, methadone is associated with QT interval prolongation, a risk that may increase with higher plasma concentrations and prolonged exposure. These factors underscore the need for cautious dosing, patient education, and, in selected cases, electrocardiographic monitoring.
Methadone’s duration of action is characterized by a short analgesic effect and a long, variable elimination half-life. This unique pharmacologic profile underlies its effectiveness in chronic pain and opioid use disorder while also contributing to its narrow therapeutic margin. Clinicians must account for these properties to maximize benefit and minimize harm when prescribing methadone.
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Withdrawal due to preoperative medication stoppage refers to the physiological and psychological disturbances that occur when chronic medications are abruptly stopped before surgery. While the cessation of certain drugs before surgery is necessary to reduce risks such as bleeding or intraoperative hemodynamic instability, abrupt stoppage can result in rebound syndromes, physiological dysregulation, and poorer surgical outcomes. Balancing the competing risks of medication continuation versus stoppage is an ongoing challenge for anesthesiologists.
Preoperative medication management involves evaluating each patient’s chronic therapy for potential interactions with anesthetic agents, the surgical stress response, and hemodynamic stability and implementing a stoppage plan when necessary, ideally one that minimizes withdrawal. However, this is often difficult in practice, whether due to the urgency of the procedure, variation in how individual patients respond to medication, or other factors.
Beta-adrenergic antagonists (β-blockers) are among the most well-documented examples of adverse symptoms upon cessation; stopping them preoperatively can cause rebound hypertension, tachycardia, and ischemia due to the upregulation of adrenergic receptors during chronic therapy (1). Multiple studies have demonstrated that continuing β-blockers throughout the perioperative period reduces cardiovascular morbidity and mortality in high-risk patients (2). Consequently, current anesthesia guidelines strongly recommend maintaining β-blockade throughout the perioperative period, except in cases of severe bradycardia or hypotension.
Similar concerns apply to centrally acting antihypertensives, such as clonidine. Abruptly stopping them may cause rebound hypertension and sympathetic overactivity, which can lead to myocardial ischemia during induction or emergence from anesthesia (3). For this reason, clonidine is usually continued until the day of surgery, and if oral administration is not possible, intravenous administration becomes an available option.
Psychotropic medications, particularly selective serotonin reuptake inhibitors (SSRIs) and serotonin-norepinephrine reuptake inhibitors (SNRIs), introduce another layer of complexity. Stoppage of these agents in the preoperative period may cause withdrawal symptoms such as dizziness, insomnia, sensory disturbances, agitation, or anxiety for 24 to 72 hours. These symptoms can mimic or exacerbate postoperative delirium and complicate anesthetic emergence. Evidence from perioperative reviews indicates that antidepressant withdrawal syndromes are clinically relevant and that these medications are best continued through the surgical period, unless there are specific contraindications, such as the potential for serotonin syndrome with monoamine oxidase inhibitors (4).
Benzodiazepine withdrawal syndromes also present significant perioperative risks. Sudden discontinuation may cause tremors, agitation, autonomic instability, or seizures. The aforementioned symptoms can overlap with postoperative delirium and complicate anesthetic recovery. Current perioperative guidelines recommend continuing benzodiazepine therapy for dependent patients or gradually tapering off if discontinuation is unavoidable. Cross-tolerant substitutes (e.g., long-acting benzodiazepines) may be used when necessary to prevent withdrawal during the perioperative period (5).
The broader issue beyond individual drug classes lies in polypharmacy and communication failures among care teams. Patients often don’t know which medications to continue or withhold before surgery, and perioperative teams may not have full medication histories. Studies show that up to 60% of surgical inpatients have at least one medication discrepancy upon admission, which increases the likelihood of inappropriate withdrawal and drug duplication (5). Therefore, medication reconciliation, multidisciplinary coordination, and patient education are crucial components of preoperative safety.
For anesthesiologists, awareness of withdrawal phenomena related to preoperative medication stoppage has practical implications for intraoperative management. Patients in withdrawal states may exhibit elevated catecholamine levels, resistance to anesthetic agents, or altered responses to opioids and sedatives. Inadequately recognized withdrawal can also confound hemodynamic monitoring and lead to misattribution of symptoms (e.g., tachycardia from β-blocker withdrawal mistakenly attributed to inadequate anesthesia). Anticipating and mitigating these effects through preoperative planning and postoperative vigilance can significantly improve surgical safety.
References
1. Pass SE, Simpson RW. Discontinuation and reinstitution of medications during the perioperative period. Am J Health Syst Pharm. 2004 May 1;61(9):899-912; quiz 913-4. PMID: 15156966.
2. Doak GJ. Discontinuing drugs before surgery. Can J Anaesth. 1997 May;44(5 Pt 2):R112-23. English, French. doi: 10.1007/BF03022270. PMID: 9196845.
3. Spell NO 3rd. Stopping and restarting medications in the perioperative period. Med Clin North Am. 2001 Sep;85(5):1117-28. doi: 10.1016/s0025-7125(05)70367-9. PMID: 11565489.
4. Zafirova Z, Vázquez-Narváez KG, Borunda D. Preoperative Management of Medications. Anesthesiol Clin. 2018;36(4):663-675. doi:10.1016/j.anclin.2018.07.012
5. Mercado DL, Petty BG. Perioperative medication management. Med Clin North Am. 2003;87(1):41-57. doi:10.1016/s0025-7125(02)00146-3
Portal hypertension produces a constellation of hemodynamic, metabolic, and hematologic changes that significantly impact anesthesia care. Most commonly, it results from cirrhosis. Because these patients often present with multisystem involvement—including cardiovascular instability, coagulopathy, variceal risk, ascites, and altered drug metabolism—anesthesiologists must tailor perioperative strategies to minimize complications and maintain physiologic stability.
One of the most notable features of portal hypertension is the development of a hyperdynamic circulatory state. Patients commonly exhibit increased cardiac output, decreased systemic vascular resistance, and impaired vascular responsiveness. These changes reduce the predictability of anesthetic drug effects and increase the risk of intraoperative hypotension. Careful titration of induction agents and vigilant hemodynamic monitoring during anesthesia and recovery are therefore essential for patients with portal hypertension. Vasodilatory anesthetics may worsen hypotension, while aggressive fluid administration can exacerbate ascites or precipitate variceal bleeding. Many guidelines recommend early use of vasopressors instead of large fluid boluses to maintain mean arterial pressure.
Another major consideration is coagulopathy. Portal hypertension is frequently accompanied by thrombocytopenia from hypersplenism, reduced hepatic synthesis of clotting factors, and altered fibrinolysis. These abnormalities increase the risk of perioperative bleeding, particularly during invasive airway management or regional anesthesia. While traditional coagulation tests can inadequately reflect the balance between pro- and anticoagulant forces, viscoelastic assays can better guide transfusion decisions. The presence of esophageal varices and portal gastropathy underscores the need for gentle airway manipulation and avoidance of nasogastric tube placement unless absolutely necessary.
Altered pharmacokinetics also play a central role in anesthetic planning. Reduced hepatic blood flow and impaired liver function influence the metabolism and clearance of many anesthetic agents, opioids, and muscle relaxants. Drugs with high hepatic extraction ratios may have prolonged effects, while protein-binding alterations increase the free fraction of several medications. Volatile anesthetics remain generally safe, but careful dosing is required. Short-acting agents with extrahepatic metabolism, such as remifentanil or cisatracurium, are often preferred.
Respiratory considerations arise primarily from ascites, hepatopulmonary syndrome, or portopulmonary hypertension. Ascites reduces functional residual capacity and compliance, predisposing patients to atelectasis during induction. Optimization strategies include preoperative paracentesis in symptomatic individuals and lung-protective ventilation with cautious PEEP. In cases of portopulmonary hypertension, elevated pulmonary pressures may lead to right ventricular failure under anesthesia. These patients benefit from avoidance of hypoxemia, hypercarbia, and acidosis, along with the potential use of pulmonary vasodilators when indicated.
Renal function also requires close attention due to indirect effects and comorbidities of portal hypertension. Hepatorenal syndrome and impaired renal perfusion increase susceptibility to intraoperative kidney injury. Maintaining adequate perfusion pressure, avoiding nephrotoxic agents, and monitoring urine output are critical components of perioperative care.
Finally, portal hypertension often signals advanced liver disease, making an in-depth preoperative and pre-anesthesia assessment vital to safe patient care. Tools such as the Child-Pugh score and Model for End-Stage Liver Disease (MELD) score help stratify perioperative risk, predict postoperative outcomes, and guide discussions regarding procedural appropriateness.
In summary, portal hypertension profoundly affects anesthesia care due to circulatory alterations, coagulopathy, impaired drug metabolism, respiratory challenges, and renal vulnerability. High-quality perioperative management requires careful assessment, meticulous intraoperative monitoring, and a tailored pharmacologic approach to ensure safe and effective anesthesia for this high-risk population.
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Telehealth, sometimes referred to as telemedicine, is the virtual delivery of health care, which can include virtually meeting with a care provider, checking results from labs or x-rays, physical or occupational therapy, and looking at skin problems.1 Compared with traditional medical appointments, telehealth appointments typically have shorter wait times and can be scheduled more flexibly, making it beneficial for some patients. A 2024 survey estimated that 54% of Americans have had a telehealth visit, with 89% feeling satisfied with their experience, signaling its status as a key component of US healthcare.2
The COVID-19 pandemic led to an expansion of telehealth services in the US. A study of over 36 million individuals in the US found that, from March to June of 2019, only 0.3% of outpatient visits were conducted via telehealth, compared to 23.6% from March to June of 2020—a staggering 766% increase within a year.3 Telehealth’s increased usage has lasted beyond the pandemic: According to the American Hospital Association, the percentage of US hospitals offering telehealth services in 2022 was 86.9%, up from 78.3% in 2019 and slightly higher than 2020 and 2021 levels.4
Doximity, an online networking service for medical professionals that also provides telehealth services, publishes an annual “State of Telemedicine Report” that provides information on the current state of telehealth in the US based on an analysis of the service usage and physician surveys. According to the most recent report, 50% of physicians who used telehealth in 2023 are 39 years old or younger.5 The most common use cases were for follow-up visits and medication management, and the specialties with the highest rates of telehealth adoption were endocrinology, urology, and gastroenterology.
The COVID-19 pandemic spurred new legislation to ease and expand access to telehealth services. For instance, the CARES Act, the $2.2 trillion stimulus package signed into law at the beginning of the pandemic, included updates to Centers for Medicaid & Medicare Services telehealth regulations that lifted restrictions on the use of telehealth. With the changes, patients in all settings, not just rural ones, could receive telehealth under Medicare. Additionally, federally qualified health centers could offer telehealth, and more telehealth services became available.6 One change expanded Medicare coverage for audio-only services, which are important for those with limited Internet access.
Various pieces of congressional legislation extended the Medicare flexibilities beyond the pandemic, but the benefits were ultimately set to expire on September 30, 2025—the same day congressional funding expired and the government shut down. As of October 26, 2025, the government remains shut down, and until it reopens, Congress cannot vote to extend the flexibilities. Kyle Zebley, senior vice president of public policy at the American Telehealth Association, noted that older and disabled Americans will be most impacted.7
In a statement on the shutdown, the Association also noted that commercial insurers often model their coverage based on Medicare coverage, so in the absence of Medicare coverage for expanded telehealth, there is “growing uncertainty in the marketplace, and concern that commercial payers could soon follow suit if Congress and the Administration do not act quickly.”8 For the millions of Americans for whom adequate health care depends on broad insurance coverage of telehealth, these circumstances could be disastrous.
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