What is the effect of slow push midazolam (Benzodiazepine)?

From the Guidelines

Slow push midazolam should be administered at a rate of 1-2 mg over 1-2 minutes for adult patients, with a total initial dose of 1-2 mg, as recommended by the most recent and highest quality study 1. When administering midazolam via slow IV push, it is crucial to monitor the patient continuously for respiratory depression, hypotension, and level of sedation, as the major side effect of midazolam is respiratory depression, which can be fatal, especially when used with an opioid 1. Some key points to consider when administering slow push midazolam include:

• The initial intravenous dose in healthy adults younger than 60 years of age is 1-2 mg (or no more than 0.03 mg/kg) injected over 1-2 minutes 1
• Additional doses of 1 mg (or 0.02-0.03 mg/kg) may be administered at 2-minute intervals until adequate sedation is achieved 1
• Patients older than 60 and those with ASA physical status III or greater require a dose reduction of 20% or more 1
• A total intravenous dose greater than 6 mg usually is not required for routine endoscopic procedures 1 It is also important to have resuscitation equipment and flumazenil (a benzodiazepine antagonist) readily available when administering midazolam, as the slow administration is crucial because rapid injection can lead to severe respiratory depression or apnea 1. Midazolam works by enhancing the effect of gamma-aminobutyric acid (GABA), the main inhibitory neurotransmitter in the brain, producing anxiolysis, sedation, amnesia, and anticonvulsant effects, with an onset of action typically within 1-2 minutes when given intravenously, and a duration of action of 15-80 minutes for most clinical effects 1.

From the Research

Midazolam-Induced Respiratory Depression

• Midazolam can cause significant depression of respiration, as seen in a study where intravenous midazolam was given to 17 patients undergoing upper G.I. endoscopy 2.
• The effects of midazolam on respiratory depression can be measured by various parameters, including oxygen saturation, minute volume, and tidal volume 3, 4.

Reversal of Midazolam-Induced Respiratory Depression by Flumazenil

• Flumazenil, a benzodiazepine antagonist, can reverse midazolam-induced sedation, but its effect on respiratory depression is inconsistent 3, 4, 5.
• Studies have shown that flumazenil can improve breathing through improved consciousness, but its effects on central respiratory depression are variable and short-lived 4, 5.
• A study found that flumazenil 0.5 mg can reverse midazolam-induced sedation completely, but is only partially effective for some parameters related to respiratory depression 3.
• Another study demonstrated that flumazenil 1.0 mg can increase minute ventilation and tidal volume to premidazolam values, but the effects diminish over time 4.

Oxygen Inhalation During Midazolam Sedation

• Inhalation of 50% oxygen during midazolam sedation does not enhance respiratory depression by midazolam, and may help prevent hypoxia 6.
• A study found that oxygen saturation was higher in patients inhaling 50% oxygen compared to those inhaling normal air during midazolam sedation, but other respiratory parameters did not differ significantly between the two groups 6.