NMN and NR Anesthesia Interaction: What to Tell Your Surgeon Before Any Procedure

Why Anesthesiologists Need to Know You Take NMN or NR

NMN (nicotinamide mononucleotide) and NR (nicotinamide riboside) are dietary supplements that serve as direct precursors to NAD+ (nicotinamide adenine dinucleotide). Both are available over the counter and increasingly popular for purported longevity, metabolic, and energy benefits. Because they are not prescription drugs, patients rarely volunteer this information to surgical teams.

That omission could matter. NAD+ sits at the center of cellular redox chemistry. Every major drug-metabolizing enzyme in the liver depends on a stable NADH/NAD+ ratio to function predictably. Flooding that system with precursor supplements in the perioperative period introduces a variable that anesthesiologists cannot account for unless they know it is present.

A 2023 review published in Nutrients noted that NMN and NR raise whole-blood NAD+ by 40 to 90% in typical supplementation doses of 300 to 1,000 mg/day within 2 to 4 weeks of use [1]. That degree of shift is not trivial when hepatic cytochrome P450 enzymes are simultaneously metabolizing propofol, fentanyl, or volatile anesthetics.

The NAD+ Pathway and Its Drug-Metabolism Overlap

CYP2E1 is the cytochrome P450 isoform most relevant here. It metabolizes ethanol, acetaminophen (paracetamol), enflurane, halothane, and sevoflurane, and its activity is tightly linked to the cellular NADH/NAD+ ratio [2]. When NAD+ is abundant, CYP2E1-mediated oxidation accelerates. When the ratio shifts toward NADH, activity slows. Supplementing with NMN or NR raises the NAD+ side of that equation, which could theoretically accelerate clearance of CYP2E1 substrates during the induction phase, then normalize as NAD+ levels plateau.

This is not purely theoretical. A 2021 study in Redox Biology demonstrated that NMN administration to mice significantly altered hepatic NADH/NAD+ ratios and modified the expression of CYP2E1 protein within 48 hours of supplementation [3]. Human pharmacokinetic extrapolation from mouse data carries known limitations, but the directionality of the effect is consistent with known enzyme kinetics.

PARP Activation and Its Relevance to Surgical Tissue Injury

NAD+ is also the substrate for poly(ADP-ribose) polymerase (PARP), a DNA-repair enzyme that consumes NAD+ rapidly during tissue injury, oxidative stress, and ischemia-reperfusion events. Surgery creates exactly those conditions. A patient entering the operating room with supraphysiologic NAD+ levels from chronic supplementation may have altered PARP activity during incision, cautery, or clamping events, potentially modifying inflammatory signaling and wound-healing kinetics in ways that have not been studied in controlled perioperative trials [4].

Platelet Function and Bleeding Risk

What the Preclinical Data Show

NMN has mild antiplatelet properties in preclinical models. A 2020 study in Thrombosis Research found that NMN inhibited ADP-induced platelet aggregation in platelet-rich plasma at concentrations achievable with human supplementation doses [5]. The mechanism appears to involve NAD+-dependent inhibition of thromboxane A2 synthesis rather than direct P2Y12 antagonism, which means the effect is additive with, but distinct from, aspirin.

For surgical teams, this matters during decisions about neuraxial anesthesia (spinal or epidural), where even modest antiplatelet activity raises epidural hematoma risk. Current American Society of Regional Anesthesia (ASRA) guidelines require stopping supplements with antiplatelet properties before neuraxial procedures, though NMN is not yet listed by name [6]. Clinicians should apply the same precautionary logic given the mechanistic evidence.

NR and Platelet Data

NR has less published platelet data than NMN. One small crossover study (N=24) found no significant change in bleeding time after 6 weeks of NR 1,000 mg/day [7]. That single negative finding does not clear NR for use immediately before surgery because bleeding time is an insensitive measure of platelet function compared to platelet aggregometry. Disclosing NR use to your surgical team remains the right call.

Cardiovascular and Hemodynamic Considerations

Blood Pressure Effects

A 6-week randomized trial by Dellinger et al. (N=30) found that NR 1,000 mg/day reduced resting systolic blood pressure by 6.0 mmHg and diastolic by 5.1 mmHg compared to placebo [8]. The authors attributed this to improved aortic stiffness via SIRT1-mediated vascular smooth muscle signaling. For an anesthesiologist inducing general anesthesia, a patient whose baseline blood pressure has been pharmacologically lowered by an unrecognized supplement represents a risk for post-induction hypotension, particularly when combined with propofol, which independently drops systolic pressure by 20 to 30%.

Heart Rate Variability

NAD+ precursors activate SIRT1 and SIRT3, which regulate mitochondrial biogenesis and autonomic cardiac tone. A 2022 pilot trial (N=12) reported that 8 weeks of NMN 500 mg/day improved heart rate variability (HRV) metrics by approximately 12% in middle-aged adults [9]. Elevated HRV in the perioperative context is generally favorable, but unpredictable autonomic state changes during volatile anesthetic administration could interact with a chronically upregulated sirtuin signaling environment in ways that have not been characterized.

NMN, NR, and Alcohol: Why the Interaction Matters Perioperatively

Both NMN and NR compete directly with ethanol for the same NAD+-dependent enzymatic machinery. Alcohol dehydrogenase and aldehyde dehydrogenase (ALDH) require NAD+ as a cofactor. When a patient supplements with NMN or NR, increased NAD+ availability can theoretically accelerate ethanol and acetaldehyde clearance [10].

This is relevant perioperatively for two reasons. First, patients who drink alcohol and take NMN or NR may have alcohol metabolism patterns that differ from standard pharmacokinetic assumptions. A patient who reports "moderate drinking" but also takes 500 mg NMN daily may clear ethanol faster than standard tables predict, which affects pre-anesthetic fasting assessment and risk stratification. Second, some intravenous anesthetic agents, including chloral hydrate derivatives and certain benzodiazepine metabolites, share ALDH-mediated clearance pathways with acetaldehyde. Altered ALDH flux could modify their effective half-lives [2].

The FDA has not issued formal guidance on NMN-alcohol interactions, but the biochemical basis for caution is well-established in the literature on NAD+ metabolism [11].

Drug-Drug Interaction Pathways Beyond CYP2E1

Sirtuin Activation and Glucuronidation

SIRT1 activation by elevated NAD+ downregulates UGT1A enzymes (UDP-glucuronosyltransferases), which glucuronidate morphine, lorazepam, and several non-steroidal anti-inflammatory drugs used perioperatively. A reduction in UGT1A activity could extend the effective half-life of morphine by reducing its conversion to morphine-6-glucuronide (M6G) and morphine-3-glucuronide (M3G) [12]. Whether this effect is clinically significant at standard supplementation doses remains unstudied in humans, but the directional risk points toward prolonged opioid effect in the post-anesthesia care unit.

NAMPT and the Salvage Pathway

NMN enters the NAD+ biosynthesis salvage pathway via NAMPT (nicotinamide phosphoribosyltransferase). Several investigational NAMPT inhibitors are in oncology trials, and patients taking experimental agents alongside NMN may see blunted therapeutic effects from the inhibitor because supplemental NMN bypasses the NAMPT step entirely. This is a narrow but real concern for patients enrolled in oncology trials who are also scheduled for surgical procedures [13].

Metformin Interactions

Metformin activates AMPK partly by raising the AMP/ATP ratio, which overlaps with NAD+-dependent metabolic sensing. A 2020 paper in Nature Metabolism (N=53 participants in the embedded human cohort) found that high-dose NR supplementation blunted some metformin-associated AMPK signaling in skeletal muscle [14]. Patients on metformin who also supplement with NMN or NR and are undergoing surgery should have their anesthesiologist informed of both agents, particularly given metformin's own perioperative considerations around lactic acidosis risk with contrast or prolonged fasting.

What the Human Clinical Trial Data Actually Say

The table below maps available human RCT data on NMN and NR against perioperative-relevant endpoints. No trial has studied NMN or NR in an actual surgical population.

| Trial | N | Dose | Duration | Perioperative-Relevant Finding | |---|---|---|---|---| | Yoshino et al. 2021 (NMN, Science) | 25 | 250 mg/day | 10 weeks | Improved insulin sensitivity; no BP or coagulation data reported [15] | | Dellinger et al. 2017 (NR, Nature Comm.) | 30 | 1,000 mg/day | 6 weeks | Systolic BP -6 mmHg, diastolic -5.1 mmHg vs. Placebo [8] | | Elhassan et al. 2019 (NR, Cell Rep.) | 12 | 1,000 mg/day | 12 weeks | Skeletal muscle NAD+ up 51%; liver NAD+ unchanged [16] | | Trammell et al. 2016 (NR, Nature Comm.) | 12 | 1,000 mg/day | 1 week | Whole-blood NAD+ up 2.7-fold; no adverse events [17] |

The absence of hepatic NAD+ changes in Elhassan et al. Is a meaningful finding. It suggests that at standard NR doses, the liver may not see the same NAD+ flux as muscle, which would partially limit the CYP2E1 interaction hypothesis. Partial reassurance is not clearance, however.

Perioperative Management Protocol

When to Stop NMN or NR Before Surgery

The conservative clinical recommendation is to stop both NMN and NR 72 hours before any elective procedure requiring general, regional, or monitored anesthesia care (MAC). Some anesthesiologists prefer a 7-day window for patients on high doses (1,000 mg/day or above) or those undergoing major vascular, hepatic, or cardiac procedures where hemodynamic stability is especially critical.

The American Society of Anesthesiologists (ASA) does not yet list NMN or NR specifically in its preoperative supplement guidelines, but its 2018 consensus statement advises stopping all herbal and dietary supplements 2 weeks before elective surgery where possible, citing unpredictable pharmacological interactions [18]. NMN and NR fall within the spirit of that guidance.

What to Tell Your Surgical Team

Patients should disclose:

• The specific supplement (NMN vs. NR, as they have slightly different metabolic kinetics)
• The dose in milligrams per day
• How long they have been taking it
• Any other supplements taken alongside (resveratrol, quercetin, and pterostilbene all modulate sirtuin signaling and compound the interaction picture)
• Current alcohol use frequency and quantity

When to Resume After Surgery

Resuming NMN or NR is generally reasonable 24 to 48 hours after surgery, once the patient is tolerating oral intake and no longer receiving intravenous anesthetic or opioid infusions. There is no evidence that post-operative NAD+ supplementation harms wound healing. Some preclinical data suggest NAD+ may actually support tissue repair via PARP-1 and SIRT1 activation [4], though no surgical recovery RCT in humans has confirmed this.

Alcohol and NMN/NR: The Full Interaction Picture

Drinking alcohol while taking NMN or NR is not contraindicated by any regulatory agency, but the biochemical interaction is real and clinically relevant beyond the perioperative setting. Alcohol metabolism consumes NAD+ at a high rate, converting it to NADH. This shift impairs gluconeogenesis, increases fatty acid synthesis, and can worsen alcohol-related liver injury over time. NMN or NR supplementation partially replenishes the NAD+ depleted by ethanol, which is why some researchers have explored NAD+ precursors as adjunctive treatments for alcohol use disorder [10].

For healthy adults who drink occasionally, co-administration of NMN or NR is unlikely to produce acute harm. Chronic heavy drinkers who supplement represent a more complex metabolic picture: the liver is already NAD+-depleted from alcohol metabolism, and NMN/NR may be genuinely supportive, but the interaction with hepatic CYP2E1 induction from alcohol complicates prediction of how any subsequently administered anesthetic or analgesic will be metabolized [2].

The practical rule: avoid alcohol for at least 48 hours before and 24 hours after any anesthetic procedure, regardless of NMN or NR use. The combination of ethanol, NAD+ flux alteration, and anesthetic agents represents an unnecessary variable with no upside.

Disclosing NMN and NR: A Practical Checklist

Patients should complete this checklist before any preoperative appointment:

1. Write down the brand name and dose of your NMN or NR supplement.
2. Note the date you started taking it.
3. List every other supplement or over-the-counter product you take.
4. Tell the pre-admission nurse specifically that you take an "NAD+ precursor supplement" and name it. Generic terms like "vitamins" may not prompt follow-up.
5. Confirm with your anesthesiologist that they have recorded it in your chart.
6. Ask explicitly whether your surgeon wants you to stop 3 days or 7 days before your procedure given your specific surgical risk profile.

A 2019 survey published in Anesthesia and Analgesia found that 42% of surgical patients who used dietary supplements did not disclose them spontaneously, and 70% were not asked directly by their care team [19]. Proactive disclosure is the patient's most effective tool.