Versed Drug: A Clinician’s Guide to Midazolam, Its Uses in Sedation and Anaesthesia, Side Effects, Respiratory Risks, and What Patients Should Know

What the Versed drug (midazolam) is, how it works as a short-acting benzodiazepine in procedural sedation, anaesthesia induction, status epilepticus, and end-of-life care, the side effects and respiratory depression risk, dosing in adults and children, the amnestic properties patients should expect, and the rare contexts in which midazolam is misused or abused.

Clinically reviewed by Dr. Ponlawat Pitsuwan, Physician and Addiction Medicine Specialist, Phuket Island Rehab.

Versed is the brand name for midazolam, a short-acting benzodiazepine widely used in medical care for procedural sedation, anaesthesia induction, status epilepticus treatment, and palliative care. The drug is given by intravenous, intramuscular, intranasal, or oral routes depending on the clinical setting. Its rapid onset of 1 to 5 minutes when given intravenously, its short duration of 30 to 60 minutes, and its profound amnestic properties make it useful for endoscopy, colonoscopy, dental procedures, and brief surgical interventions. The principal risks of midazolam administration are respiratory depression (particularly when combined with opioids), hypotension, paradoxical agitation, and prolonged sedation in older patients or those with hepatic impairment. The minutes of onset and offset make the drug useful for outpatient procedures but require careful monitoring. Common side effects include drowsiness, nausea, headache, and the characteristic anterograde amnesia for events during the sedation period. The medication is a Schedule IV controlled substance with abuse potential, though recreational midazolam use is uncommon compared to oral benzodiazepines because the drug is primarily a hospital and procedure medication. Patients receiving the Versed drug should have respiratory and cardiac monitoring throughout, recovery support before discharge, and should not drive or operate machinery for 24 hours afterward.

What the Versed drug is and the brand history

Versed is the most common brand name for midazolam, a short-acting benzodiazepine that has been a cornerstone of procedural sedation, anaesthesia, and emergency medicine since its FDA approval in 1986. The drug was developed by the pharmaceutical company Hoffmann-La Roche, the same company that produced the original chlordiazepoxide (Librium) and diazepam (Valium), and was designed specifically to provide the anxiolytic and sedative effects of the older benzodiazepines with a faster onset and shorter duration suitable for procedural use. The original Versed brand has been joined by numerous generic midazolam formulations and the medication is now available across virtually all hospitals worldwide.

The medication used in procedural and anaesthetic contexts comes in several formulations. The injectable form (1 mg/mL or 5 mg/mL solution) is the most common in hospital settings and is given by intravenous, intramuscular, or rectal routes. An oral syrup formulation is approved for paediatric procedural sedation. An intranasal spray formulation became FDA-approved in 2019 as Nayzilam specifically for the treatment of seizure clusters in patients with epilepsy. A buccal formulation is available in some countries for the same indication. The wide range of formulations reflects the drug’s value across different acute clinical contexts.

The chemical structure of midazolam is distinctive among benzodiazepines because it contains an imidazole ring that becomes water-soluble at acidic pH and lipid-soluble at physiological pH. This property is what allows midazolam to be formulated as an aqueous injection that does not require the propylene glycol carrier used for diazepam and lorazepam, and it is part of why the drug has a fast onset when given intravenously: the lipid solubility at body pH allows rapid crossing of the blood-brain barrier.

How midazolam works in the brain and body

Midazolam works in the body and brain by binding to the gamma-aminobutyric acid type A receptor, specifically at the benzodiazepine binding site on the alpha subunit. The binding allosterically enhances the action of GABA, the primary inhibitory neurotransmitter in the central nervous system. The enhanced inhibition produces sedation, anxiolysis, anterograde amnesia, anticonvulsant activity, and skeletal muscle relaxation. At higher doses the inhibition extends to the respiratory centres in the brainstem, producing the dose-dependent respiratory depression that is the most important medical risk of midazolam administration.

The pharmacokinetics of midazolam are what make the drug distinctive in clinical practice. When given intravenously, the onset of action is 1 to 5 minutes, the peak effect is at 5 to 10 minutes, and the duration of clinically useful sedation is typically 30 to 60 minutes in healthy adults. The elimination half-life is 2 to 6 hours in adults with normal liver and kidney function, substantially shorter than chlordiazepoxide (24 to 48 hours), diazepam (20 to 100 hours), or lorazepam (10 to 20 hours). The short half-life is the main reason midazolam is preferred over the older benzodiazepines for procedural sedation: the patient can recover quickly and be discharged after a brief procedure.

Metabolism occurs primarily in the liver by the CYP3A4 enzyme system, producing 1-hydroxymidazolam as the major metabolite. The metabolite is then conjugated to the inactive glucuronide and excreted in urine. The CYP3A4 dependence means that midazolam levels are significantly affected by drugs that inhibit or induce that enzyme. Strong inhibitors including ketoconazole, itraconazole, clarithromycin, ritonavir, and grapefruit juice can substantially increase midazolam plasma levels and prolong its effect. Strong inducers including rifampin, carbamazepine, phenytoin, and St. John’s Wort can reduce midazolam levels. Patients with hepatic impairment metabolise the drug more slowly and require dose reduction.

Procedural sedation: the most common indication for Versed

Procedural sedation is the single most common use of the Versed drug in current medical practice. The medication is used to provide anxiolysis, sedation, and amnesia during procedures including upper endoscopy, colonoscopy, dental work, transvaginal ultrasound, bronchoscopy, cardiac catheterisation, electrical cardioversion, fracture reduction, abscess drainage, and minor surgical procedures performed under local anaesthesia. The goal of procedural sedation is to allow the procedure to proceed safely while the patient remains comfortable and has no memory of the experience afterward.

The typical adult dose for intravenous procedural sedation is 0.5 to 2 mg given over several minutes, with additional 0.5 to 1 mg doses titrated every few minutes to the desired level of sedation. The total cumulative dose for a routine procedure is usually 2 to 5 mg, though longer or more painful procedures may require higher doses. Combination with an opioid analgesic such as fentanyl is common when the procedure is expected to be painful; the combination produces excellent sedation and analgesia but also increases the respiratory depression risk and requires careful monitoring.

Pre-procedural assessment before midazolam administration includes review of the patient’s medical history, current medications (particularly other CNS depressants), allergies, prior anaesthetic experience, current fasting status, and airway examination. The American Society of Anesthesiologists physical status classification is used to identify patients at higher risk, with class III or higher requiring more intensive monitoring or anaesthesiology involvement. Patients are typically required to fast for 6 hours before elective procedural sedation to reduce aspiration risk, though emergency procedures may need to proceed without full fasting under appropriate precautions.

Monitoring during procedural sedation is essential. Standard monitoring includes continuous pulse oximetry, intermittent or continuous blood pressure measurement, cardiac rhythm monitoring, capnography (end-tidal carbon dioxide monitoring), and clinical observation of the patient’s level of consciousness and respiratory effort. Capnography is increasingly emphasised because it detects respiratory depression earlier than pulse oximetry alone, particularly in patients receiving supplemental oxygen who can maintain normal saturation despite significant hypoventilation. The minutes of close monitoring during and after the procedure are what allow midazolam to be used safely.

Anaesthesia induction and maintenance

Midazolam is used as part of balanced anaesthesia for many types of surgery, typically combined with a fast-onset induction agent such as propofol and an opioid analgesic. The role of midazolam in anaesthesia is to provide pre-operative anxiolysis (often given 30 to 60 minutes before the patient enters the operating room), to provide intra-operative sedation and amnesia during regional or local anaesthesia procedures, and to support induction of general anaesthesia. The typical induction dose is 0.1 to 0.3 mg/kg given intravenously, often combined with fentanyl and propofol for full induction.

The respiratory depression effect of midazolam combined with opioids and other induction agents requires careful airway management. Patients undergoing general anaesthesia are intubated and ventilated mechanically, which neutralises the respiratory depression risk. Patients undergoing regional anaesthesia (spinal or epidural) with midazolam sedation are spontaneously breathing and require respiratory monitoring throughout. The combination of midazolam with propofol and an opioid for moderate sedation outside the operating room produces strong sedation, profound respiratory depression in vulnerable patients, and is the highest-risk procedural sedation context outside of full general anaesthesia.

Intensive care unit (ICU) sedation in mechanically ventilated patients is another common use of midazolam, particularly as a continuous infusion at 0.02 to 0.10 mg/kg/hour. The drug is used to keep the intubated patient comfortable, to reduce the work of breathing on the ventilator, to facilitate procedures, and to reduce the metabolic demand during severe illness. Prolonged ICU use of midazolam (more than 48 to 72 hours) is increasingly minimised because it is associated with delirium, prolonged mechanical ventilation, ICU-acquired weakness, and increased mortality compared to lighter sedation strategies. Current ICU practice favours dexmedetomidine or propofol over midazolam for routine ICU sedation in most patients.

Side effects of midazolam

The dominant side effect of midazolam is dose-dependent sedation, which is the desired effect in most clinical uses but can extend beyond the intended period and produce prolonged drowsiness. Other common side effects include nausea and vomiting (particularly in the recovery period after procedural sedation), headache, hiccups, mild hypotension, and the characteristic anterograde amnesia that prevents the patient from remembering events during and shortly after the sedation. Most patients tolerate the medication well and recover without difficulty.

Respiratory depression is the most important serious side effect and the leading cause of midazolam-related morbidity and mortality. The risk is highest when midazolam is combined with opioids, in older patients, in patients with chronic obstructive pulmonary disease or obstructive sleep apnoea, and in patients receiving doses faster than the recommended titration rate. Hypoxemia, hypercarbia, and progression to respiratory arrest can occur, particularly in unmonitored settings. The respiratory depression risk is what makes midazolam administration outside of healthcare settings particularly dangerous and what underlies the requirement for trained personnel and monitoring equipment whenever the medication is used.

Cardiovascular effects of midazolam include mild dose-dependent hypotension, particularly with rapid intravenous administration. Most patients tolerate the cardiovascular effects without difficulty, but patients with significant aortic stenosis, hypovolemia, or cardiac dysfunction may experience more dramatic blood pressure drops. The nervous system effects beyond the desired sedation include occasional paradoxical reactions with agitation, confusion, hostility, or aggression (more common in children, older adults, and patients with developmental disability or traumatic brain injury), and rarely seizures during emergence from sedation.

The anterograde amnesia produced by midazolam is one of its most clinically useful properties and one of its most ethically complicated. Patients who have had endoscopy, colonoscopy, dental work, or other procedures under midazolam sedation typically have no memory of the procedure itself and often have only fragmentary memory of the recovery period. The amnesia is helpful for preventing procedural distress and traumatic memory but means the patient cannot give informed consent during the procedure and cannot provide useful feedback about their experience during it. This is part of why pre-procedural informed consent is so important when midazolam is being used.

Status epilepticus and seizure emergencies

Status epilepticus, defined as a single seizure lasting longer than 5 minutes or two or more seizures without recovery of consciousness between them, is a neurological emergency that requires immediate treatment to prevent permanent brain injury and death. Midazolam is one of the first-line treatments for status epilepticus, administered as intramuscular injection (10 mg in adults), intranasal spray (5 mg in each nostril for total 10 mg), or buccal solution. The fast onset and ability to be given without intravenous access make midazolam particularly useful in pre-hospital settings, in patients who are actively seizing and difficult to access intravenously, and in children where IV access can be challenging.

The RAMPART trial published in the New England Journal of Medicine in 2012 compared intramuscular midazolam to intravenous lorazepam for treatment of status epilepticus in the pre-hospital setting and found that intramuscular midazolam was at least as effective with a faster time to seizure termination, primarily because IV access could not be obtained quickly in the field. This study established intramuscular midazolam as the standard pre-hospital seizure treatment in many jurisdictions. The intranasal and buccal formulations have similar efficacy and are now widely used by family members and caregivers for patients with seizure clusters or known status epilepticus risk.

The dose used for status epilepticus is higher than the procedural sedation dose and produces deep sedation as part of its mechanism of stopping the seizure. The patient typically remains drowsy or unconscious for several hours after seizure termination and may require airway support during this period. Continued seizures despite first-line midazolam treatment require escalation to other antiepileptic medications including levetiracetam, fosphenytoin, or valproate, and eventually to general anaesthesia with propofol or pentobarbital for refractory status epilepticus.

Use of midazolam in paediatrics and older adults

Paediatric use of midazolam includes pre-operative anxiolysis, procedural sedation for imaging studies or minor procedures, treatment of paediatric status epilepticus, and ICU sedation. The oral syrup formulation is widely used for pre-operative anxiolysis in children at 0.25 to 0.5 mg/kg about 20 to 30 minutes before separation from parents. The intranasal route at 0.2 to 0.4 mg/kg is used when faster onset is needed. Intravenous dosing is similar to adult weight-based dosing at 0.05 to 0.1 mg/kg. Paediatric patients are particularly susceptible to paradoxical reactions and require careful monitoring.

Older adults are at substantially elevated risk of adverse effects from midazolam, with prolonged sedation, deeper respiratory depression, post-procedure delirium, and increased fall risk all more common than in younger adults. The American Geriatrics Society Beers Criteria list midazolam as a medication to use with caution in older adults, particularly outside of procedural and emergency contexts. Dose reduction by 25 to 50 percent is typical in patients over 65, and additional dose reduction is warranted in patients over 75 or those with significant medical comorbidity, hepatic impairment, or polypharmacy.

Patients with chronic obstructive pulmonary disease, obstructive sleep apnoea, severe heart failure, advanced liver disease, or chronic kidney disease all require dose reduction and intensified monitoring. The respiratory depression risk in patients with underlying pulmonary disease can be dramatic, and the prolonged effect in patients with hepatic impairment can extend the sedation by hours. Pre-procedural assessment specifically should identify these vulnerabilities and inform the dosing and monitoring plan.

Misuse, abuse, and dependence

Midazolam is a Schedule IV controlled substance in the United States and is recognised as having abuse potential, though recreational midazolam use is uncommon compared to oral benzodiazepines such as alprazolam, lorazepam, and clonazepam. The drug’s primary recreational use occurs when it is diverted from medical settings, either by healthcare workers with access to hospital supplies or by patients who have been prescribed the intranasal or buccal formulations for seizure indications. The recreational effects sought are anxiolysis, sedation, and the dissociative quality that high doses can produce, similar to the effects sought from other benzodiazepines.

Healthcare worker diversion of midazolam is a recognised problem in hospital settings, and many institutions have implemented strict tracking and accountability measures for the drug. Anaesthesiologists, emergency physicians, intensive care nurses, and dental practitioners have all been involved in documented diversion cases, sometimes culminating in personal addiction and rarely in patient harm when diluted or counterfeit drug is administered. Awareness of healthcare worker addiction is part of the broader recognition that medical professionals are at elevated risk of substance use disorders involving the medications they prescribe.

Physical dependence on midazolam can develop with prolonged ICU sedation or with long-term oral or intranasal use, and abrupt discontinuation produces withdrawal symptoms similar to those of other benzodiazepines. Withdrawal includes anxiety, insomnia, tremor, sweating, and in severe cases seizures. Patients who have received continuous midazolam infusion in the ICU for more than 7 to 10 days typically require a gradual taper rather than abrupt discontinuation. The taper is usually managed by ICU teams using the existing infusion that is gradually reduced over days to weeks.

Drug interactions with midazolam

The most clinically important drug interactions with midazolam involve CYP3A4 modulators. Strong CYP3A4 inhibitors substantially increase midazolam plasma levels and prolong its effect. These include the antifungals ketoconazole, itraconazole, voriconazole, and posaconazole; the macrolide antibiotics clarithromycin and erythromycin; the protease inhibitors used for HIV including ritonavir, lopinavir, and atazanavir; the calcium channel blocker diltiazem; and grapefruit juice consumed in significant quantities. Patients on these medications need significant midazolam dose reduction or use of an alternative benzodiazepine.

Strong CYP3A4 inducers reduce midazolam levels and may produce inadequate sedation at standard doses. These include rifampin, rifabutin, carbamazepine, phenytoin, phenobarbital, and St. John’s Wort. Patients on these medications may require higher midazolam doses to achieve the desired effect, with continued attention to the respiratory depression risk that does not disappear at the higher doses required.

Drug interactions with other central nervous system depressants are the most important clinical consideration. Opioids substantially increase the respiratory depression risk and contribute to most midazolam-related deaths. Alcohol, other benzodiazepines, barbiturates, and z-drugs (zolpidem, eszopiclone, zaleplon) all add to the sedation and respiratory depression. Patients undergoing procedural sedation should be asked specifically about alcohol consumption, illicit drug use, and use of recreational benzodiazepines that might not appear on their medication list.

When sedative medications and drinking have become more than occasional

For readers who have undergone procedures with Versed and have noticed that they enjoyed the sedation, or who have started taking oral midazolam or other benzodiazepines outside of their prescribed indication, the situation may have moved into problematic substance use territory. Recreational benzodiazepine use is one of the more under-recognised forms of substance use in adult populations. People who take a friend’s Xanax to manage social anxiety, who take leftover Valium from a procedure for sleep, or who fill repeat midazolam prescriptions for ongoing anxiety may be drifting toward a use pattern that meets criteria for substance use disorder.

Heavy drinking commonly coexists with recreational benzodiazepine use because the two substances enhance each other’s effects and because the personality and life circumstances that drive heavy drinking are similar to those that drive benzodiazepine misuse. The combination of regular drinking with regular benzodiazepine use produces substantial cognitive impairment, dependence on two cross-tolerant substances, and significant overdose risk when doses escalate or new substances are introduced. The patient in this pattern often does not see either substance as a problem because each appears to be a manageable part of their daily routine, but the cumulative effect on their function is often substantial.

Alcohol use disorder, the clinical term for problematic alcohol use, is defined by the DSM-5 criteria including drinking more than intended, unsuccessful efforts to cut down, craving, tolerance, withdrawal, and continued use despite consequences. Many people who use benzodiazepines recreationally also meet AUD criteria without recognising it. Phuket Island Rehab provides residential addiction medicine treatment for alcohol use disorder, benzodiazepine dependence, and dual diagnosis cases that include co-occurring anxiety, depression, or sleep disorders.

Summary

The Versed drug is the brand name for midazolam, a short-acting benzodiazepine widely used in medical care for procedural sedation, anaesthesia induction, status epilepticus treatment, and ICU sedation. The drug acts at the GABA-A receptor to produce dose-dependent sedation, anxiolysis, anterograde amnesia, anticonvulsant activity, and at higher doses respiratory depression. The fast onset of 1 to 5 minutes when given intravenously and the short duration of 30 to 60 minutes make midazolam well suited to outpatient procedural sedation. The principal risks are respiratory depression, particularly when combined with opioids; hypotension; paradoxical agitation; and prolonged sedation in older patients or those with hepatic impairment. Standard monitoring during midazolam administration includes pulse oximetry, capnography, blood pressure, and continuous clinical observation. Recreational midazolam use is uncommon but the drug carries Schedule IV controlled-substance status because of its abuse potential. As Dr. Ponlawat Pitsuwan summarises, “Midazolam is one of the most useful medications in modern medical care when given by trained personnel with proper monitoring. The same drug given without monitoring, or combined with opioids in inappropriate settings, has been responsible for thousands of preventable deaths over the past several decades. The minutes of attention during administration are what make it safe.”

Frequently asked questions

What is Versed used for?

Versed (midazolam) is used primarily for procedural sedation during endoscopy, colonoscopy, dental procedures, and minor surgical interventions; for anaesthesia induction; for treatment of status epilepticus and seizure emergencies; for ICU sedation in mechanically ventilated patients; and for palliative care symptom management in end-of-life situations.

How long does the Versed drug take to work?

When given intravenously, midazolam produces sedation within 1 to 5 minutes, with peak effect at 5 to 10 minutes. When given intramuscularly, onset is 5 to 15 minutes. Intranasal or buccal formulations produce onset in 5 to 10 minutes. Oral midazolam syrup takes 15 to 30 minutes to reach peak effect.

How long do the effects of Versed last?

Clinically useful sedation from a single intravenous dose lasts 30 to 60 minutes in healthy adults. The elimination half-life is 2 to 6 hours. Most patients recover full alertness within 2 to 4 hours, though residual cognitive and motor impairment can persist for up to 24 hours, and patients are advised not to drive or operate machinery for at least 24 hours after the sedation.

What are the side effects of Versed?

Common side effects include drowsiness, anterograde amnesia (loss of memory for events during sedation), nausea, vomiting, headache, hiccups, and mild hypotension. Serious side effects include respiratory depression (especially when combined with opioids), paradoxical agitation, and rarely seizures during emergence. Older patients and those with hepatic impairment are at elevated risk of adverse effects.

Is Versed addictive?

Midazolam is a Schedule IV controlled substance with abuse potential. Physical dependence can develop with prolonged daily use or extended ICU infusions. Recreational midazolam use is uncommon compared to oral benzodiazepines, but the drug is sometimes diverted from medical settings. Patients with prior benzodiazepine use disorder should inform their provider before procedural sedation with midazolam.

Can Versed be reversed?

Yes. Flumazenil is a benzodiazepine antagonist that can reverse midazolam-induced sedation when given intravenously. It is reserved for cases of significant respiratory depression or prolonged sedation requiring reversal, and is not used routinely after procedural sedation. Flumazenil has a shorter half-life than midazolam, so re-sedation can occur after the reversal wears off.

Sources

• U.S. Food and Drug Administration (FDA). Midazolam (Versed) prescribing information. https://www.accessdata.fda.gov/drugsatfda_docs/label/2017/018654s075lbl.pdf
• Silbergleit R, Durkalski V, Lowenstein D, et al; NETT Investigators. Intramuscular versus intravenous therapy for prehospital status epilepticus. New England Journal of Medicine. 2012;366(7):591-600. https://www.nejm.org/doi/full/10.1056/NEJMoa1107494
• American Society of Anesthesiologists. Practice Guidelines for Moderate Procedural Sedation and Analgesia 2018. Anesthesiology. 2018;128(3):437-479. https://pubs.asahq.org/anesthesiology/article/128/3/437/19283
• U.S. Food and Drug Administration (FDA). Boxed warning on opioid and benzodiazepine combination. https://www.fda.gov/drugs/drug-safety-and-availability/fda-drug-safety-communication-fda-warns-about-serious-risks-and-death-when-combining-opioid-pain-or
• American Geriatrics Society Beers Criteria Update Expert Panel. 2023 AGS Beers Criteria. https://agsjournals.onlinelibrary.wiley.com/doi/10.1111/jgs.18372
• Glauser T, Shinnar S, Gloss D, et al. Evidence-Based Guideline: Treatment of Convulsive Status Epilepticus in Children and Adults. Epilepsy Currents. 2016;16(1):48-61. https://journals.sagepub.com/doi/10.5698/1535-7597-16.1.48
• Substance Abuse and Mental Health Services Administration (SAMHSA). National helpline. https://www.samhsa.gov/find-help/national-helpline

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