From the Guidelines
Versed (midazolam) administered intramuscularly (IM) can cause significant side effects, including respiratory depression, which is the most serious and potentially life-threatening adverse effect, as reported in studies such as 1.
Common Side Effects
The common side effects of midazolam administered IM include:
- Respiratory depression
- Decreased blood pressure
- Headache
- Nausea
- Vomiting
- Hiccups
- Pain at the injection site These side effects are well-documented in the literature, with studies such as 1 and 1 highlighting the importance of monitoring patients for these adverse effects.
Serious Side Effects
More serious but less common side effects of midazolam administered IM include:
- Severe respiratory depression
- Apnea
- Cardiac arrest
- Allergic reactions These serious side effects can be life-threatening and require immediate medical attention, as noted in 1.
Special Considerations
Elderly patients and those with respiratory conditions are at higher risk for adverse effects from midazolam administered IM, as reported in 1. The IM route typically produces effects within 15 minutes, lasting 1-6 hours depending on dosage. Patients receiving Versed IM should be monitored for breathing and vital signs, should not drive or operate machinery for 24 hours after administration, and should avoid alcohol and other CNS depressants during this time, as recommended in 1.
Mechanism of Action
The side effects of midazolam occur because it enhances the inhibitory neurotransmitter GABA in the brain, which slows central nervous system activity, as explained in 1. This mechanism of action is responsible for both the intended effects of sedation, drowsiness, and amnesia, as well as the potential side effects.
From the FDA Drug Label
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 BECAUSE SERIOUS AND LIFE-THREATENING CARDIORESPIRATORY ADVERSE EVENTS HAVE BEEN REPORTED, PROVISION FOR MONITORING, DETECTION AND CORRECTION OF THESE REACTIONS MUST BE MADE FOR EVERY PATIENT TO WHOM MIDAZOLAM HYDROCHLORIDE INJECTION IS ADMINISTERED, REGARDLESS OF AGE OR HEALTH STATUS Excessive single doses or rapid intravenous administration may result in respiratory depression, airway obstruction and/or arrest
The side effects of Midazolam (Versed) administered intramuscularly (IM) include:
- Respiratory depression
- Airway obstruction
- Agitation
- Involuntary movements (including tonic/clonic movements and muscle tremor)
- Hyperactivity
- Combativeness 2 2
From the Research
Side Effects of Midazolam (Versed) Administered Intramuscularly (IM)
- The most commonly reported adverse effects of midazolam are hiccups, cough, nausea, and vomiting 3
- Midazolam has been associated with respiratory depression and cardiac arrest when used in combination with an opioid, particularly in the elderly, although all ages are at risk for respiratory depression 3
- Intramuscular midazolam can cause sedation and respiratory depression, with the optimal dose per unit body weight being lower in men than in women to prevent over-sedation and respiratory depression 4
- Midazolam administered intramuscularly may be useful in a variety of epileptic seizures during childhood, with seizures stopping 1-10 min after injection in most cases 5
- The water solubility of midazolam allows for rapid and reliable absorption of the drug from the intramuscular injection site, with minimal local irritation 6
Respiratory Effects
- Midazolam can cause a significant decrease in minute ventilation (MV) and tidal volume (TV), with a corresponding increase in respiratory rate (RR) 7
- Elderly patients may experience greater reductions in MV and TV, with a lack of compensatory RR increase 7
- Respiratory depression can lead to hypercarbia and/or hypoxemia, and may heighten the risk of other respiratory complications 7
Reversal of Adverse Effects
- Many of the adverse effects associated with midazolam can be reversed rapidly by the administration of flumazenil, a competitive benzodiazepine receptor antagonist 3