^ Cytochrome P -3a4 Inhibitors
Concomitant administration with drugs that are known to inhibit the P450-3A4 enzyme system, such as cimetidine (not ranitidine), erythromycin, diltiazem, verapamil, ketoconazole and itraconazole, may result in prolonged sedation due to a decrease in plasma clearance of midazolam.
The effect of single oral doses of 800 mg cimetidine and 300 mg ranitidine on steady-state concentrations of midazolam was examined in a randomized crossover study (n=8). Cimetidine increased the mean midazolam steady-state concentration from 57 to 71 ng/mL. Ranitidine increased the mean steady-state concentration to 62 ng/mL. No change in choice reaction time or sedation index was detected after dosing with the H2 receptor antagonists.
In a placebo-controlled study, erythromycin administered as a 500 mg dose, three times a day, for 1 week (n=6), reduced the clearance of midazolam following a single 0.5 mg/kg intravenous dose. The half-life was approximately doubled.
The effects of diltiazem (60 mg three times a day) and verapamil (80 mg three times a day) on the pharmacokinetics and pharmacodynamics of oral midazolam were investigated in a three-way crossover study (n=9). The half-life of midazolam increased from 5 to 7 hours when midazolam was taken in conjunction with verapamil or diltiazem. No interaction was observed in healthy subjects between midazolam and nifedipine.
^ Pharmacodynamics
The effects of midazolam on the CNS are dependent on the dose administered, the route of administration, and the presence or absence of other medications.
^ Abuse
Midazolam in 0.9% Sodium Chloride Injection contains the benzodiazepine, midazolam. Benzodiazepines are a class of sedative drugs with a known potential for abuse. Abuse is the intentional, non-therapeutic use of a drug, even once, for its desirable psychological or physiological effects.
Misuse is the intentional use, for therapeutic purposes, of a drug by an individual in a way other than prescribed by a health care provider or for whom it was not prescribed. Drug addiction is a cluster of behavioral, cognitive, and physiological phenomena that may include a strong desire to take the drug, difficulties in controlling drug use (e.g., continuing drug use despite harmful consequences, giving a higher priority to drug use than other activities and obligations), and possible tolerance or physical dependence. Both abuse and misuse may lead to addiction. Midazolam was actively self-administered in primate models used to assess the positive reinforcing effects of psychoactive drugs. Midazolam produced physical dependence of a mild to moderate intensity in cynomolgus monkeys after 5 to 10 weeks of administration. Available data concerning the drug abuse and dependence potential of midazolam suggest that its abuse potential is at least equivalent to that of diazepam.
^ Description
Midazolam in 0.9% Sodium Chloride Injection is a benzodiazepine available as a sterile, preservative-free, nonpyrogenic solution of midazolam and sodium chloride in water for injection for intravenous use. Each single-dose bag of Midazolam in 0.9% Sodium Chloride Injection contains either 50 mg per 50 mL (1 mg per mL) or 100 mg per 100 mL (1 mg per mL) of midazolam and 9 mg/mL of sodium chloride in water for injection. Midazolam in 0.9% Sodium Chloride Injection may contain hydrochloric acid and/or sodium hydroxide for pH adjustment. The pH is approximately 2.5 to 3.5.
Midazolam is a white or yellowish powder, practically insoluble in water, Chemically, midazolam is 8-chloro-6-(2-fluorophenyl)-1-methyl-4H-imidazo[1,5-a][1,4]-benzodiazepine. Midazolam has the empirical formula C18 H13ClFN3, a calculated molecular weight of 325.8 and the following structural formula:
^ Risk Of Cardiorespiratory Adverse Reactions
Serious cardiorespiratory adverse reactions have occurred after administration of midazolam. These have included respiratory depression, airway obstruction, oxygen desaturation, apnea, respiratory arrest and/or cardiac arrest, sometimes resulting in death or permanent neurologic injury. There have also been rare reports of hypotensive episodes requiring treatment during or after diagnostic or surgical manipulations particularly in adult or pediatric patients with hemodynamic instability. Hypotension occurred more frequently in the sedation studies in patients premedicated with an opioid. Excessive single doses or rapid intravenous administration may result in respiratory depression, airway obstruction and/or arrest. When used for sedation/anxiolysis/amnesia, midazolam should always be titrated slowly in adult or pediatric patients. Adverse hemodynamic events have been reported in pediatric patients with cardiovascular instability; rapid intravenous administration should also be avoided in this population. Continuously monitor patients for early signs of hypoventilation, airway obstruction, and apnea using capnography, pulse oximetry, and clinical assessment [see Dosage and Administration (2.2)].
^ Drug/laboratory Test Interactions
Midazolam has not been shown to interfere with results obtained in clinical laboratory tests.
^ Saquinavir
In a placebo-controlled study, saquinavir administered as a 1200 mg dose, tid, for 5 days (n=12), a 56% reduction in the clearance of midazolam following a single 0.05 mg/kg intravenous dose was observed. The half-life was approximately doubled.
^ Risk Of Hypotension And Seizure In Preterm Infants And Neonates
Rapid injection should be avoided in the neonatal population. Midazolam administered rapidly as an intravenous injection (i.e., less than 2 minutes) has been associated with severe hypotension in neonates, particularly when the patient has also received fentanyl. Likewise, severe hypotension has been observed in neonates receiving a continuous infusion of midazolam who then receive a rapid intravenous injection of fentanyl. Seizures have been reported in several neonates following rapid intravenous administration.
The neonate also has reduced and/or immature organ function and is also vulnerable to profound and/or prolonged respiratory effects of midazolam.
^ Debilitation And Comorbid Considerations
Higher risk adult and pediatric surgical patients, elderly patients and debilitated adult and pediatric patients require lower dosages, whether or not concomitant sedating medications have been administered. Adult or pediatric patients with COPD are unusually sensitive to the respiratory depressant effect of midazolam. Pediatric and adult patients undergoing procedures involving the upper airway such as upper endoscopy or dental care, are particularly vulnerable to episodes of desaturation and hypoventilation due to partial airway obstruction. Adult and pediatric patients with chronic renal failure and patients with congestive heart failure eliminate midazolam more slowly [see Clinical Pharmacology (12.3)]. Because elderly patients frequently have inefficient function of one or more organ systems and because dosage requirements have been shown to decrease with age, reduced initial dosage of midazolam is recommended, and the possibility of profound and/or prolonged effect should be considered.
Do not administer Midazolam in 0.9% Sodium Chloride Injection to adult or pediatric patients in shock or coma, or in acute alcohol intoxication with depression of vital signs. Particular care should be exercised in the use of intravenous midazolam in adult or pediatric patients with uncompensated acute illnesses, such as severe fluid or electrolyte disturbances.
^ Impaired Cognitive Function
Midazolam is associated with a high incidence of partial or complete impairment of recall for the next several hours. The decision as to when patients who have received injectable midazolam, particularly on an outpatient basis, may again engage in activities requiring complete mental alertness, operate hazardous machinery or drive a motor vehicle must be individualized. Gross tests of recovery from the effects of midazolam [see Clinical Pharmacology (12.3)] cannot be relied upon to predict reaction time under stress. It is recommended that no patient operate hazardous machinery or a motor vehicle until the effects of the drug, such as drowsiness, have subsided or until one full day after anesthesia and surgery, whichever is longer. For pediatric patients, particular care should be taken to assure safe ambulation.
^ Pediatric Neurotoxicity
Published animal studies demonstrate that the administration of anesthetic and sedation drugs that block NMDA receptors and/or potentiate GABA activity increase neuronal apoptosis in the developing brain and result in long-term cognitive deficits when used for longer than 3 hours. The clinical significance of these findings is not clear. However, based on the available data, the window of vulnerability to these changes is believed to correlate with exposures in the third trimester of gestation through the first several months of life, but may extend out to approximately three years of age in humans [see Nonclinical Pharmacology (13.2)].
Some published studies in children suggest that similar deficits may occur after repeated or prolonged exposures to anesthetic agents early in life and may result in adverse cognitive or behavioral effects. These studies have substantial limitations, and it is not clear if the observed effects are due to the anesthetic/sedation drug administration or other factors such as the surgery or underlying illness.
Anesthetic and sedation drugs are a necessary part of the care of children needing surgery, other procedures, or tests that cannot be delayed, and no specific medications have been shown to be safer than any other. Decisions regarding the timing of any elective procedures requiring anesthesia should take into consideration the benefits of the procedure weighed against the potential risks.
^ Dependence
Midazolam may produce physical dependence after long-term use. Physical dependence is a state that develops as a result of physiological adaptation in response to repeated drug use, manifested by withdrawal signs and symptoms after abrupt discontinuation or a significant dose reduction of a drug. If Midazolam in 0.9% Sodium Chloride Injection is administered long-term (i.e., for several days to weeks), abrupt discontinuation or rapid dosage reduction, or administration of flumazenil, a benzodiazepine antagonist, may precipitate acute withdrawal reactions, including seizures, which can be life-threatening. Patients at an increased risk of withdrawal adverse reactions after benzodiazepine discontinuation or rapid dosage reduction include those who take higher dosages (i.e., higher and/or more frequent doses) and those who have had longer durations of use [see Warnings and Precautions (5.5)].
To reduce the risk of withdrawal reactions, after extended therapy, do not abruptly discontinue Midazolam in 0.9% Sodium Chloride Injection. Gradually taper the dosage using a tapering schedule that is individualized to the patient.
^ Safe Discontinuation Of Midazolam In % Sodium Chloride Injection After Long-term Use
If Midazolam in 0.9% Sodium Chloride Injection is administered long-term (for several days to weeks), do not abruptly discontinue. Gradually taper the dosage in physically-dependent patients using a tapering schedule that is individualized to the patient [see Warnings and Precautions (5.5)].
^3 Dosage Forms And Strengths
Midazolam in 0.9% Sodium Chloride Injection, 50 mg per 50 mL (1 mg per mL) and 100 mg per 100 mL (1 mg per mL), is a clear, colorless solution supplied in single-dose bags with an aluminum overwrap.
^ Neonatal Sedation And Withdrawal Syndrome
Receiving Midazolam in 0.9% Sodium Chloride Injection late in pregnancy can result in sedation (respiratory depression, lethargy, hypotonia) and/or withdrawal symptoms (hyperreflexia, irritability, restlessness, tremors, inconsolable crying, and feeding difficulties) in the neonate. Monitor neonates exposed to Midazolam in 0.9% Sodium Chloride Injection during pregnancy or labor for signs of sedation and manage these neonates accordingly [see Use in Specific Populations (8.1)].
^ Risk Of Increased Intraocular Pressure In Patients With Glaucoma
Benzodiazepines, including Midazolam in 0.9% Sodium Chloride Injection, can increase intraocular pressure in patients with glaucoma. Measurements of intraocular pressure in patients without eye disease show a moderate lowering following induction with midazolam. Midazolam in 0.9% Sodium Chloride Injection may be used in patients with open-angle glaucoma only if they are receiving appropriate therapy. Patients with open-angle glaucoma may need to have their ophthalmologic status evaluated following treatment with Midazolam in 0.9% Sodium Chloride Injection. Midazolam in 0.9% Sodium Chloride Injection is contraindicated in patients with narrow-angle glaucoma.
^ Pediatric Use
The safety and efficacy of midazolam for sedation/anxiolysis/amnesia following continuous infusion have been established in pediatric and neonatal patients. UNLIKE ADULT PATIENTS, PEDIATRIC PATIENTS GENERALLY RECEIVE INCREMENTS OF MIDAZOLAM ON A MG/KG BASIS. As a group, pediatric patients generally require higher dosages of midazolam (mg/kg) than do adults. Younger (less than six years) pediatric patients may require higher dosages (mg/kg) than older pediatric patients, and may require closer monitoring. In obese PEDIATRIC PATIENTS, the dose should be calculated based on ideal body weight. When midazolam is given in conjunction with opioids or other sedatives, the potential for respiratory depression, airway obstruction, or hypoventilation is increased. The health care practitioner who uses this medication in pediatric patients should be aware of and follow accepted professional guidelines for pediatric sedation appropriate to their situation.
Midazolam should not be administered by rapid injection in the neonatal population. Severe hypotension and seizures have been reported following rapid intravenous administration, particularly, with concomitant use of fentanyl.
^ Other Drugs Used In The Surgical Setting
No significant adverse interactions with commonly used premedications or drugs used during anesthesia and surgery (including atropine, scopolamine, glycopyrrolate, diazepam, hydroxyzine, d-tubocurarine, succinylcholine and other nondepolarizing muscle relaxants) or topical local anesthetics (including lidocaine, dyclonine HCl and Cetacaine) have been observed in adults or pediatric patients. In neonates, however, severe hypotension has been reported with concomitant administration of fentanyl. This effect has been observed in neonates on an infusion of midazolam who received a rapid injection of fentanyl and in patients on an infusion of fentanyl who have received a rapid injection of midazolam.
^4 Contraindications
Midazolam in 0.9% Sodium Chloride Injection is contraindicated in patients with:
^ Animal Toxicology And/or Pharmacology
Published studies in animals demonstrate that the use of anesthetic agents during the period of rapid brain growth or synaptogenesis results in widespread neuronal and oligodendrocyte cell loss in the developing brain and alterations in synaptic morphology and neurogenesis. Based on comparisons across species, the window of vulnerability to these changes is believed to correlate with exposures in the third trimester through the first several months of life, but may extend out to approximately 3 years of age in humans.
In primates, exposure to 3 hours of an anesthetic regimen that produced a light surgical plane of anesthesia did not increase neuronal cell loss, however, treatment regimens of 5 hours or longer increased neuronal cell loss. Data in rodents and in primates suggest that the neuronal and oligodendrocyte cell losses are associated with subtle but prolonged cognitive deficits in learning and memory. The clinical significance of these nonclinical findings is not known, and health care providers should balance the benefits of appropriate anesthesia in neonates and young children who require procedures against the potential risks suggested by the nonclinical data [see Warnings and Precautions (5.8)].
^ How Supplied/storage And Handling
Midazolam in 0.9% Sodium Chloride Injection is a clear, colorless solution supplied in single-dose bags with an aluminum overwrap available as:
Store at 20° to 25°C (68° to 77°F); excursions permitted between 15° and 30°C (59° and 86°F). [See USP Controlled Room Temperature.] Individual containers may be used up to 48 hours after initial penetration.
Do not freeze. Discard unused portion. Sterile, Nonpyrogenic, Preservative-free, PVC-free, DEHP-free.The container closure is not made with natural rubber latex.
^ Risk Of Dependence And Withdrawal With Long-term Use Of Midazolam In % Sodium Chloride Injection
The continued use of benzodiazepines for several days to weeks may lead to clinically significant physical dependence. If used for long-term use (i.e., for several days to weeks), abrupt discontinuation or rapid dosage reduction of midazolam, or administration of flumazenil, a benzodiazepine antagonist, may precipitate acute withdrawal reactions, including seizures, which can be life-threatening.
Patients at an increased risk of withdrawal adverse reactions after benzodiazepine discontinuation or rapid dosage reduction include those who take higher dosages (i.e., higher and/or more frequent doses) and those who have had longer durations of use.
After extended therapy, do not abruptly discontinue Midazolam in 0.9% Sodium Chloride Injection. When discontinuing midazolam in a physically-dependent patient, gradually taper the dosage using a tapering schedule that is individualized to the patient [see Dosage and Administration (2.3), Dependence (9.3)].
^ Geriatric Use
Because geriatric patients may have altered drug distribution and diminished hepatic and/or renal function, reduced doses of midazolam are recommended. Doses of Midazolam in 0.9% Sodium Chloride Injection should be decreased for elderly and for debilitated patients [see Warnings and Precautions (5.6) and Dosage and Administration (2)] and subjects over 70 years of age may be particularly sensitive. These patients will also probably take longer to recover completely after midazolam administration for the induction of anesthesia. Administration of intravenous midazolam to elderly and/or high-risk surgical patients has been associated with rare reports of death under circumstances compatible with cardiorespiratory depression. In most of these cases, the patients also received other central nervous system depressants capable of depressing respiration, especially opioids [see Dosage and Administration (2)].
Midazolam is known to be substantially excreted by the kidney, and the risk of adverse reactions to this drug may be greater in patients with impaired renal function. Because elderly patients are more likely to have decreased renal function, care should be taken in dose selection, and it may be useful to monitor renal function.
^ Dosing Recommendations
Table 1 provides dosing recommendations for adult, pediatric, and neonatal patients.
^Warning: Personnel And Equipment For Monitoring And Resuscitation And Risks From Concomitant Use With Opioid Analgesics And Other Sedative-hypnotics
Personnel and Equipment for Monitoring and Resuscitation
Risks from Concomitant Use with Opioid Analgesics and Other Sedative Hypnotics
Concomitant use of benzodiazepines, including Midazolam in 0.9% Sodium Chloride Injection, and opioids may result in profound sedation, respiratory depression, coma, and death. Continuously monitor patients for respiratory depression and depth of sedation [see Warnings and Precautions (5.2) and Drug Interaction (7.1)].
^ Risks From Concomitant Use With Opioids, Other Sedative Hypnotics, Or Other Central Nervous System Depressants
Concomitant use of benzodiazepines and opioids may result in profound sedation, respiratory depression, coma, and death. Monitor patients for respiratory depression and sedation [see Warnings and Precautions (5.2) and Drug Interactions (7.1)].
Titrate the dose of Midazolam in 0.9% Sodium Chloride Injection when administered with opioid analgesics and sedative-hypnotics to the desired clinical response.
Continuously monitor sedated patients for hypotension, airway obstruction, hypoventilation, apnea, and oxygen desaturation. These cardiorespiratory effects may be more likely to occur in patients with obstructive sleep apnea, the elderly, and ASA‑PS III or IV patients.
Concomitant use of barbiturates, alcohol, or other central nervous system depressants may increase the risk of hypoventilation, airway obstruction, desaturation, or apnea and may contribute to profound and/or prolonged drug effect. Narcotic premedication also depresses the ventilatory response to carbon dioxide stimulation.
^ Risk Of Intra-arterial Injection
There have been limited reports of intra-arterial injection of midazolam. Adverse events have included local reactions, as well as isolated reports of seizure activity in which no clear causal relationship was established. Precautions against unintended intra-arterial injection should be taken. Extravasation should also be avoided.
The safety and efficacy of Midazolam in 0.9% Sodium Chloride Injection following nonintravenous routes of administration have not been established. Midazolam in 0.9% Sodium Chloride Injection should only be administered intravenously.
^ Opioid Analgesics And Other Sedative Hypnotics
The concomitant use of benzodiazepines and opioids increases the risk of respiratory depression because of actions at different receptor sites in the CNS that control respiration. Benzodiazepines interact at GABAA sites and opioids interact primarily at mu receptors. When benzodiazepines and opioids are combined, the potential for benzodiazepines to significantly worsen opioid-related respiratory depression exists. Monitor patients closely for respiratory depression and sedation.
The sedative effect of intravenous midazolam is accentuated by any concomitantly administered medication which depresses the central nervous system, particularly opioids (e.g., morphine, meperidine and fentanyl) and also secobarbital and droperidol. Consequently, the dosage of midazolam should be adjusted according to the type and amount of concomitant medications administered and the desired clinical response [see Dosage and Administration (2)].
^ Important Dosage And Administration Instructions
Midazolam must never be used without individualization of dosage particularly when used with other medications capable of producing central nervous system depression [see Warnings and Precautions (5.2)].
Midazolam in 0.9% Sodium Chloride Injection can cause respiratory depression. It is a potent sedative agent that requires slow administration and individualization of dosage. Excessive single doses or rapid intravenous administration may result in respiratory depression, airway obstruction and/or arrest. Continuously monitor patients for early signs of hypoventilation, airway obstruction, and apnea using capnography, pulse oximetry, and clinical assessment [see Warnings and Precautions (5.3)].
Reactions such as agitation, involuntary movements, hyperactivity and combativeness have been reported in adult and pediatric patients. Should such reactions occur, the response to each dose of midazolam and all other drugs, including local anesthetics, should be evaluated before proceeding. Reversal of such responses with flumazenil has been reported in pediatric patients [see Warnings and Precautions (5.4)].
Visually inspect parenteral drug products for particulate matter and discoloration prior to administration, whenever solution and container permit. If solution is discolored or particulate matter is present, do not use.
^ Halothane
The intravenous administration of midazolam decreases the minimum alveolar concentration (MAC) of halothane required for general anesthesia. This decrease correlates with the dose of midazolam administered; no similar studies have been carried out in pediatric patients but there is no scientific reason to expect that pediatric patients would respond differently than adults.
^6 Adverse Reactions
The following serious adverse reactions are discussed in greater detail in other sections:
The following adverse reactions have been identified from literature or postmarketing reports of midazolam. Because some of these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure.
Fluctuations in vital signs were the most frequently seen findings following parenteral administration of midazolam in adults and included decreased tidal volume and/or respiratory rate decrease (23.3% of patients following intravenous administration) and apnea (15.4% of patients following intravenous administration), as well as variations in blood pressure and pulse rate. The majority of serious adverse reactions, particularly those associated with oxygenation and ventilation, have been reported when midazolam is administered with other medications capable of depressing the central nervous system. The incidence of such events is higher in patients undergoing procedures involving the airway without the protective effect of an endotracheal tube, (e.g., upper endoscopy and dental procedures).
^ Pancuronium
Although the possibility of minor interactive effects has not been fully studied, midazolam and pancuronium have been used together in patients without noting clinically significant changes in dosage, onset or duration in adults. Midazolam does not protect against the characteristic circulatory changes noted after administration of succinylcholine or pancuronium and does not protect against the increased intracranial pressure noted following administration of succinylcholine. Midazolam does not cause a clinically significant change in dosage, onset or duration of a single intubating dose of succinylcholine; no similar studies have been carried out in pediatric patients but there is no scientific reason to expect that pediatric patients would respond differently than adults.
^ Controlled Substance
Midazolam in 0.9% Sodium Chloride Injection contains midazolam, a Schedule IV controlled substance.
^ Pharmacokinetics
Midazolam's activity is primarily due to the parent drug. Elimination of the parent drug takes place via hepatic metabolism of midazolam to hydroxylated metabolites that are conjugated and excreted in the urine. Six single-dose pharmacokinetic studies involving healthy adults yield pharmacokinetic parameters for midazolam in the following ranges: volume of distribution (Vd), 1.0 to 3.1 L/kg; elimination half-life, 1.8 to 6.4 hours (mean approximately 3 hours); total clearance (Cl), 0.25 to 0.54 L/hr/kg. In a parallel group study, there was no difference in the clearance, in subjects administered 0.15 mg/kg (n=4) and 0.30 mg/kg (n=4) intravenous doses indicating linear kinetics. The clearance was successively reduced by approximately 30% at doses of 0.45 mg/kg (n=4) and 0.6 mg/kg (n=5) indicating non-linear kinetics in this dose range.
^ Thiopental
A moderate reduction in induction dosage requirements of thiopental (about 15%) has been noted following use of intramuscular midazolam for premedication in adults.
^ Personnel And Equipment For Monitoring And Resuscitation
^1 Indications And Usage
Midazolam in 0.9% Sodium Chloride Injection is indicated:
^ Risk Of Paradoxical Behavior
Reactions such as agitation, involuntary movements (including tonic/clonic movements and muscle tremor), hyperactivity and combativeness have been reported in both adult and pediatric patients. These reactions may be due to inadequate or excessive dosing or improper administration of midazolam; however, consideration should be given to the possibility of cerebral hypoxia or true paradoxical reactions. Should such reactions occur, the response to each dose of midazolam and all other drugs, including local anesthetics, should be evaluated before proceeding. Reversal of such responses with flumazenil has been reported in pediatric patients.
^ General Dosing Information
Individualize dosing and titrate to desired clinical response, taking into account patient age, clinical status, and concomitant use of other CNS depressants. Titrate to effect with multiple small doses while continuously monitoring respiratory and cardiac function (i.e., pulse oximetry). To minimize the potential for oversedation, allow adequate time between doses to achieve peak central nervous system effect (3 to 5 minutes).
^ Mechanism Of Action
Midazolam is a short-acting benzodiazepine central nervous system (CNS) depressant.