Patients should inform their dentist about any medications they are taking, including all prescription and over-the-counter drugs, nutritional supplements or herbal medications.

Because nitrous oxide is a sedative, the most significant drug interactions may occur with other medications that sedate or depress the central nervous system (CNS). This includes medications used for anxiety, muscle tension, pain, insomnia and seizure disorders. The combination of CNS depressants and nitrous oxide may lead to a state of unconsciousness.

Symptoms of nitrous oxide overdose can be similar to the medication’s side effects, but are usually more severe. Increased sleepiness may indicate hypoxia (lack of oxygen in body tissue) and can lead to unconsciousness. This can occur when a patient receives too high a concentration of nitrous oxide in the gas. To help prevent this, the machines used to dispense the gas are equipped with safety features that may include an audible alarm system or automatic turnoff when the percentage of oxygen in the gas is too low or the oxygen tank is empty.

If a patient reports symptoms of side effects that may indicate overdose, a dentist will most likely turn off the flow of nitrous oxide and allow the patient to breathe pure oxygen through the mask for at least five minutes. This flushes any remaining gas from the patient’s lungs. Any effects of the nitrous oxide should cease after this is done. Also, this will prevent momentary hypoxia as the nitrous oxide exits the blood.