From the Guidelines
For a 90-minute procedure, nitrous oxide is typically administered at a concentration of 30-70% in oxygen via inhalation, titrated to achieve the desired level of sedation while maintaining patient consciousness, and lorazepam (Ativan) can be administered intravenously at 0.5-2 mg given slowly over 2-5 minutes. The onset of nitrous oxide is rapid (30-60 seconds) and recovery occurs within 5 minutes after discontinuation 1. Lorazepam's effects begin within 5 minutes and last 6-8 hours, making it suitable for longer procedures like this 90-minute one 1.
Key Considerations
- When using these agents together, doses should be reduced by approximately 30-50% to prevent oversedation.
- Continuous monitoring of vital signs including oxygen saturation, heart rate, blood pressure, and respiratory rate is essential throughout the procedure.
- The patient should be NPO (nothing by mouth) for at least 6 hours before sedation, and should have a responsible adult to accompany them home afterward.
Mechanism of Action
- Nitrous oxide provides analgesic and anxiolytic effects through NMDA receptor antagonism.
- Lorazepam enhances GABA inhibitory effects in the central nervous system.
Potential Side Effects
- The major risk of nitrous oxide is hypoxia, which is avoided by coadministration with 30% to 50% oxygen 1.
- Lorazepam's major side effect is respiratory depression, which can be exacerbated by concurrent opioid use 1.
From the FDA Drug Label
The FDA drug label does not answer the question.
From the Research
Nitrous Oxide and Lorazepam Dosing Regimens
- The provided studies do not directly address the typical dosing regimens for nitrous oxide and lorazepam (Ativan) for a 90-minute procedure 2, 3, 4, 5, 6.
- However, a study on nitrous oxide and midazolam sedation found that the combination of the two agents can be effective in reducing fear and anxiety associated with dental procedures, with a significant reduction in the dose of midazolam required for inducing sedation 5.
- Another study found that the addition of nitrous oxide to a standard regimen of chloral hydrate and hydroxyzine modified some behaviors but not physiologic parameters in sedated children 6.
- A study comparing intranasal fentanyl and inhaled nitrous oxide to intravenous ketamine and midazolam for painful orthopedic procedures in a pediatric emergency department found that both strategies had similar efficacy, but the intranasal fentanyl and nitrous oxide strategy was associated with a lower risk of adverse events and shorter length of stay 4.
- The dosing regimens for nitrous oxide and lorazepam may vary depending on the specific procedure, patient population, and institutional protocols, but the available evidence suggests that combination therapy with nitrous oxide and a benzodiazepine such as midazolam or lorazepam can be effective in reducing anxiety and discomfort during medical procedures 2, 3, 5, 6.
- It is essential to consult the relevant medical literature and guidelines for specific dosing recommendations, as the provided studies do not provide a clear answer to the question of typical dosing regimens for nitrous oxide and lorazepam for a 90-minute procedure 2, 3, 4, 5, 6.