When a premature or critically ill newborn requires surgery, the drugs used to manage their pain typically include opioids like morphine and fentanyl for primary pain relief, sedatives such as midazolam and dexmedetomidine, non-opioid analgesics like acetaminophen, and inhaled anesthetics such as sevoflurane. These medications are administered in carefully calibrated doses because neonatal physiology differs dramatically from that of older children and adults — immature liver enzymes, different drug distribution patterns, and a developing brain all complicate what might otherwise be straightforward pharmacology. Consider a 28-week premature infant born weighing just over two pounds who needs emergency surgery for necrotizing enterocolitis: the anesthesiologist must balance adequate pain control against the reality that nearly none of these drugs carry FDA approval for use in this age group. The stakes of getting neonatal pain management right extend well beyond the operating room. Research has established that NICU infants undergo a mean of roughly 7.5 to 17.3 invasive procedures per day, and newborns admitted to a NICU endure an average of 134 painful procedures in just the first two weeks of life.
Some infants experience more than 3,000 painful procedures during their entire NICU stay. Despite this staggering burden, nearly 80 percent of newborns in intensive care have pain that goes untreated. For readers of this site who follow brain health and neurological development, the implications are significant — repeated, unmanaged pain in the neonatal period has been linked to altered brain development and long-term neurodevelopmental consequences. This article walks through each major drug class used in NICU surgical pain management, from opioids and sedatives to non-opioid alternatives and general anesthesia. It also covers the FDA’s safety warning about anesthetics and the developing brain, the American Academy of Pediatrics’ current guidelines, non-pharmacological pain interventions, and the shift toward multimodal analgesia strategies designed to reduce cumulative opioid exposure in the most vulnerable patients.
Table of Contents
- What Are the Primary Drugs Used for Pain Management During Infant Surgery in the NICU?
- How Does General Anesthesia Affect the Developing Neonatal Brain?
- The Rise of Dexmedetomidine in Neonatal Intensive Care
- Non-Pharmacological Pain Interventions and How They Compare to Medication
- Why Does Neonatal Pain So Often Go Untreated?
- Chloral Hydrate and Other Sedation-Only Agents
- The Future of NICU Pain Management — Multimodal and Opioid-Sparing Strategies
- Conclusion
- Frequently Asked Questions
What Are the Primary Drugs Used for Pain Management During Infant Surgery in the NICU?
The cornerstone of surgical pain control in the NICU remains opioid analgesics, with morphine and fentanyl leading the list. Morphine is the most commonly used opioid analgesic for pain relief in ventilated neonates, typically administered as a low-dose continuous infusion at 0.01 mg/kg/hr as first-line analgesia and sedation. Its use has shown the second greatest absolute increase in NICU medication use between 2010 and 2018, reflecting both growing awareness of neonatal pain and expanded protocols for its treatment. Fentanyl, which is 50 to 100 times more potent than morphine, provides rapid-onset analgesia and studies show it delivers equivalent pain relief with fewer side effects — particularly less gastrointestinal impact, which matters considerably for neonates with fragile digestive systems. For short surgical procedures where rapid recovery is needed, remifentanil offers a distinct advantage: it is cleared by plasma esterases independently of liver enzyme maturity, making it especially useful in neonates whose hepatic systems are not yet fully developed. Beyond opioids, sedatives play a critical supporting role.
Midazolam, a benzodiazepine, is the most commonly used sedative in the NICU, prescribed in approximately 31.8 percent of cases in cross-sectional studies. It provides sedation, muscle relaxation, and amnesia, but clinicians must understand a key limitation: midazolam has limited analgesic effect. A baby receiving only midazolam may appear calm and still while actually experiencing significant pain. This distinction between sedation and analgesia is one of the most important concepts in neonatal pain management, and confusing the two has historically contributed to the undertreatment of pain in this population. Non-opioid analgesics round out the pharmacological toolkit. Intravenous acetaminophen, dosed at 15 mg/kg four times daily, is increasingly used in multimodal approaches to reduce opioid exposure, particularly on the first postoperative day. Ketorolac, an NSAID given at 0.3 mg/kg four times daily intravenously, offers another non-opioid option but carries an important restriction: it is not recommended for infants under three to six months of age, limiting its utility in the youngest NICU patients.
How Does General Anesthesia Affect the Developing Neonatal Brain?
Sevoflurane is the most widely used inhaled anesthetic for neonatal surgery, and its safety profile in the youngest patients has been a subject of intense scrutiny. On December 14, 2016, the FDA issued a safety warning that general anesthetics — including sevoflurane — used in children under three years old for procedures lasting more than three hours or involving repeated exposure may affect brain development. The warning covers 11 common anesthetic and sedation agents and was based on both animal studies showing neuronal cell death and emerging human data suggesting possible developmental effects. For families already navigating the stress of a NICU stay, this warning can be alarming. However, the clinical picture is more nuanced than the FDA warning alone suggests. The GAS and PANDA clinical trials — two of the largest and most rigorous studies on this question — found no significant cognitive impairments after single, brief sevoflurane exposures.
This provides meaningful reassurance for the many NICU surgeries that are relatively short, such as central line placements, circumcisions under anesthesia, or minor abdominal procedures. The concern remains most relevant for infants requiring prolonged or repeated surgeries, such as those with complex congenital heart disease who may undergo multiple cardiac procedures in their first year of life. For a brain health audience, the distinction matters. The FDA warning does not mean that a single necessary surgery will harm a baby’s brain. What it does mean is that clinicians should minimize anesthetic exposure when possible — using the shortest effective duration, avoiding unnecessary repeated procedures under general anesthesia, and increasingly turning to regional anesthesia techniques and multimodal drug regimens that can reduce the total dose of general anesthetic agents. The ongoing research in this area continues to refine our understanding of which exposures carry meaningful risk and which do not.
The Rise of Dexmedetomidine in Neonatal Intensive Care
Few drugs have transformed NICU pain and sedation practice as rapidly as dexmedetomidine, an alpha-2 adrenergic agonist that has seen explosive growth in neonatal use. Between 2010 and 2018, dexmedetomidine showed the greatest relative increase of any medication in NICU use. More specifically, continuous infusion use increased fivefold from 7.9 percent to 44.1 percent between 2014 and 2024. By 2022 to 2024, the combination of morphine plus dexmedetomidine had become the most common continuous infusion regimen, used in 28.7 percent of cases. A 2024 systematic review confirmed that dexmedetomidine can be administered safely in neonates at specific dosage ranges, further bolstering clinical confidence. What makes dexmedetomidine appealing is its pharmacological profile. Unlike midazolam, it provides both sedation and some degree of analgesia.
Unlike opioids, it does not cause significant respiratory depression — a critical advantage in fragile neonates who may already have compromised respiratory function. It produces a sedation state that more closely resembles natural sleep, and patients can be aroused more easily for neurological assessments. In a practical example, a NICU team managing a post-surgical infant on mechanical ventilation might choose a morphine-dexmedetomidine combination specifically because it allows them to use a lower morphine dose while maintaining adequate comfort, thereby reducing opioid-related side effects like ileus and respiratory depression. The rapid adoption of dexmedetomidine also highlights a broader pattern in neonatal pharmacology: drugs are frequently adopted into widespread NICU use well before they receive formal FDA approval for neonates. This is not unique to dexmedetomidine. Neither morphine nor clonidine is FDA-approved for use in infants, yet both are among the most commonly used drugs in the NICU. Clinicians rely on extrapolated data from adult and pediatric studies, institutional protocols, and emerging neonatal-specific research to guide dosing — a reality that underscores the importance of ongoing research and standardized guidelines in this field.
Non-Pharmacological Pain Interventions and How They Compare to Medication
The American Academy of Pediatrics’ 2016 guidelines on neonatal pain management emphasize that drug therapy should not be the only tool in the clinician’s arsenal. Proven non-pharmacological interventions include kangaroo care (skin-to-skin contact), breastfeeding, non-nutritive sucking on a pacifier, oral sucrose administration, facilitated tucking (gently holding the infant in a flexed position), and swaddling. These approaches are used for mild to moderate procedural pain — such as heel sticks, venipuncture, or routine eye exams — or as adjuncts to medication during more painful procedures. The tradeoff between pharmacological and non-pharmacological approaches is not simply about choosing one over the other. For a routine blood draw, oral sucrose combined with non-nutritive sucking may provide sufficient comfort without exposing the infant to any drug at all.
For a surgical procedure, non-pharmacological methods alone would be wholly inadequate, but they can reduce the total amount of medication needed when used alongside opioids or sedatives. The practical comparison looks something like this: a post-operative infant receiving morphine for incisional pain might need fewer dose escalations if simultaneously receiving kangaroo care from a parent, because the skin-to-skin contact helps modulate stress hormones and provides sensory input that competes with pain signaling. This layered approach is the foundation of multimodal pain management. One important caveat is that non-pharmacological interventions require staff time, parent availability, and institutional support — resources that are not always abundant in busy NICUs. Kangaroo care, for instance, requires a parent to be physically present and a nurse willing to facilitate the transfer of a potentially fragile infant with multiple lines and monitors. In units with high patient-to-nurse ratios or limited parental visiting hours, these evidence-based interventions may be underutilized despite their proven benefits.
Why Does Neonatal Pain So Often Go Untreated?
The statistic that nearly 80 percent of NICU newborns have untreated pain demands examination. Several factors converge to create this gap. First, neonates cannot verbalize pain, so clinicians must rely on behavioral and physiological pain assessment tools. The AAP recommends validated instruments such as the Premature Infant Pain Profile (PIPP), the Neonatal Facial Coding System, and the Neonatal Pain and Sedation Scale, but these tools require training, time to administer, and consistent application — and many NICUs still do not use them systematically. A nurse caring for three or four critically ill neonates simultaneously may not have the bandwidth to perform formal pain assessments at the recommended intervals. Second, there has historically been a pervasive misconception that neonates do not feel pain in the same way older children and adults do, or that they will not remember painful experiences and therefore do not need the same level of pain management.
This view has been thoroughly debunked by neuroscience research showing that neonates have fully functional pain pathways and may actually have heightened pain sensitivity due to immature descending inhibitory mechanisms. The consequences of untreated pain are not limited to immediate suffering — repeated painful stimuli in the neonatal period have been associated with altered pain processing, changes in brain microstructure, and neurodevelopmental differences that persist into childhood and beyond. Third, legitimate concerns about drug side effects in neonates create a damaging paradox. Clinicians worried about opioid-related respiratory depression, the neurotoxicity warning for general anesthetics, or the lack of FDA-approved neonatal formulations may err on the side of undertreating pain. The AAP has addressed this directly, recommending that each institution develop written, stepwise pain-prevention and treatment plans based on current evidence. The goal is to replace individual clinician uncertainty with standardized protocols that ensure consistent, appropriate pain management across all patients.
Chloral Hydrate and Other Sedation-Only Agents
Chloral hydrate occupies a specific niche in NICU pharmacology. Prescribed in approximately 20.4 percent of cases in cross-sectional studies, it is used when sedation but not analgesia is required — most commonly for diagnostic imaging procedures like MRI scans. A typical scenario involves a stable NICU infant who needs a brain MRI to evaluate for intraventricular hemorrhage: the baby needs to remain perfectly still for 30 to 45 minutes but is not in pain, making chloral hydrate an appropriate choice over opioids or other analgesics that would carry unnecessary side effects.
The distinction between sedation-only agents and analgesics matters clinically because using the wrong category can mask pain without treating it. An infant given chloral hydrate for a painful procedure would appear quiet and still — potentially leading the care team to believe pain was adequately managed — while actually experiencing unmitigated pain. This is why accurate identification of the pain source, careful selection of the appropriate drug class, and consistent use of validated pain assessment tools are all essential components of responsible NICU pain management.
The Future of NICU Pain Management — Multimodal and Opioid-Sparing Strategies
The field of neonatal pain management is moving decisively toward multimodal analgesia — combining acetaminophen, dexmedetomidine, and regional or local anesthesia techniques to reduce cumulative opioid exposure in neonates. This shift is driven by growing evidence about the potential effects of opioids on the developing brain, including altered neurodevelopment and the risk of neonatal abstinence syndrome with prolonged use. A 2025 review in Neonatal Network specifically highlighted the integration of these opioid-sparing approaches for postoperative pain in NICU infants.
Regional anesthesia techniques — such as caudal blocks, peripheral nerve blocks, and even epidural catheters adapted for neonatal use — represent one of the most promising frontiers. When a surgeon and anesthesiologist can provide effective local pain control at the surgical site, the infant’s need for systemic opioids drops substantially. Combined with scheduled acetaminophen and a dexmedetomidine infusion for background sedation, this multimodal approach can dramatically reduce the total morphine-equivalent dose a neonate receives during and after surgery. For a population that may already face neurodevelopmental challenges due to prematurity or congenital conditions, minimizing unnecessary drug exposure to the developing brain is not an abstract goal — it is a clinical imperative that aligns directly with the long-term brain health outcomes that matter most.
Conclusion
NICU pain management during infant surgery draws on a carefully calibrated combination of opioids, sedatives, non-opioid analgesics, general anesthetics, and non-pharmacological interventions. Morphine and fentanyl remain the primary agents for surgical pain, while dexmedetomidine has rapidly emerged as a transformative addition that provides sedation and analgesia with a more favorable side-effect profile. The FDA’s 2016 warning about anesthetic neurotoxicity in children under three has appropriately increased caution without eliminating the use of necessary surgical anesthesia, and the reassuring findings from the GAS and PANDA trials have helped clinicians contextualize that risk. Non-pharmacological approaches and validated pain assessment tools are essential supporting elements that too many NICUs still underutilize.
The trajectory of this field points clearly toward multimodal, opioid-sparing strategies that combine regional anesthesia, acetaminophen, and dexmedetomidine to protect the developing brain while ensuring adequate pain control. For families with infants in the NICU, understanding these drug categories and asking care teams about their pain management protocols is both reasonable and important. For clinicians, the AAP’s recommendation to implement written, stepwise pain-prevention plans based on current evidence remains the standard to meet. The 80 percent untreated pain statistic is not a fixed reality — it is a challenge that better protocols, better training, and better pharmacological tools are actively working to change.
Frequently Asked Questions
Is morphine safe for premature babies?
Morphine is the most commonly used opioid for pain relief in ventilated neonates, with established dosing protocols such as 0.01 mg/kg/hr continuous infusion. However, it is not FDA-approved for infant use. Clinicians use it based on extensive clinical experience and research data, monitoring closely for side effects including respiratory depression and gastrointestinal slowing.
Does anesthesia cause brain damage in newborns?
The FDA issued a 2016 warning that general anesthetics used in children under three for procedures lasting more than three hours or with repeated exposure may affect brain development. However, the GAS and PANDA clinical trials found no significant cognitive impairments after single, brief anesthetic exposures. The risk appears most relevant for prolonged or repeated procedures, not short, one-time surgeries.
How do NICU nurses measure pain in babies who cannot talk?
Validated pain assessment tools recommended by the American Academy of Pediatrics include the Premature Infant Pain Profile (PIPP), the Neonatal Facial Coding System, and the Neonatal Pain and Sedation Scale. These tools use behavioral indicators such as facial expressions, cry patterns, and body movements, along with physiological measures like heart rate and oxygen saturation changes.
What is dexmedetomidine and why is it increasingly used in NICUs?
Dexmedetomidine is an alpha-2 adrenergic agonist that provides both sedation and analgesia without significant respiratory depression. Its use in continuous NICU infusions increased fivefold from 7.9 percent to 44.1 percent between 2014 and 2024. By 2022 to 2024, morphine plus dexmedetomidine became the most common continuous infusion regimen at 28.7 percent of cases.
Can parents help manage their baby’s pain in the NICU?
Yes. Kangaroo care (skin-to-skin contact), breastfeeding, and facilitated tucking are evidence-based non-pharmacological interventions that the AAP recommends for mild to moderate procedural pain or as adjuncts to medication. Parents should ask their NICU team about participating in these approaches during and after painful procedures.
How many painful procedures does a typical NICU baby experience?
Research shows NICU infants undergo a mean of 7.5 to 17.3 invasive procedures per day, with the EPIPPAIN study finding a median of 10 painful procedures daily. Newborns admitted to a NICU undergo an average of 134 painful procedures in the first two weeks, and some infants experience more than 3,000 painful procedures during their entire stay.
