_______________________________________________________ Treating the Apprehensive Dental Patient
Triazolam Triazolam is a benzodiazepine frequently used for the treatment of short-term insomnia, but it has become a popular medica- tion for the oral sedation of apprehensive dental patients. A sublingual formulation is available with very rapid onset of action (i.e., within 30 minutes of administration). The peak blood plasma concentration occurs approximately 75 minutes after the initial dose, with a bioavailability of 44% with conven- tional tablets or 53% with the sublingual formulation [34]. It is not available in intravenous or intramuscular formulations. Triazolam has muscle relaxant, hypnotic, sedative, and amnesic properties, which can reduce memories associated with the unpleasant aspects of dental treatment [35]. The initial dose of triazolam is 0.125–0.375 mg one hour before the appointment, with a second incremental dose at two hours into treatment (for longer procedures). A 0.5 mg maximum cumulative dose is allowed per treatment session. Compared with diazepam, triazolam has a much shorter half- life (1.5 to 5 hours), as it does not produce active metabolites that perpetuate its clinical effect [36]. These pharmacokinetic properties make it an ideal oral sedative for patients undergoing dental procedures of short-to-intermediate length. Although triazolam has many beneficial qualities for oral sedation, its use is not without risk. The FDA has assigned triazolam pregnancy risk factor X, which indicates that studies have demonstrated fetal abnormalities or fetal risk that outweighs any benefits of its use [37]. As such, this agent is contraindicated in pregnancy. Alcohol and other sedative medications can potentiate the effects of triazolam and should not be used concurrently with this medication. The patient’s physician should be consulted about the simultaneous use of other medications for chronic anxiety or depression to determine if their combination is appropriate. Some medications used in the treatment of oral infections can also have adverse interactions with triazolam. The azole antifungal agents ketoconazole and itraconazole, which are used to treat the intraoral candidiasis, can prolong the dura- tion of the effect of triazolam. Macrolide antibiotics (e.g., erythromycin, clarithromycin) to treat odontogenic bacterial infections can increase the blood plasma levels of triazolam and amplify its effect [38]. Triazolam should not be used as an anxiolytic medication if the patient is utilizing these antifungal or antibiotic medications. Lorazepam Lorazepam is an intermediate-acting benzodiazepine with a half-life of approximately 10 to 20 hours—longer than triazolam, but shorter than diazepam. This property makes lorazepam a good choice for patients who are undergoing longer dental procedures. The usual adult dose for oral seda- tion is 0.5–4 mg two hours before dental treatment; another dose may be taken the night before the appointment for those patients whose anxiety will interrupt their sleep [39].
The onset of action begins within 60 minutes of administra- tion, with peak plasma levels achieved within one to two hours. Lorazepam has antianxiety, hypnotic, amnesic, and muscle relaxant properties. It uses phase II hepatic metabo- lism, resulting in quick elimination of inactivate metabolites by the kidneys [30]. Thus, the metabolism of lorazepam is less influenced by alterations in hepatic function. Lorazepam is considered pregnancy risk factor D and should be avoided in pregnant patients. Alcohol and CNS depressant medications should not be used simultaneously with lorazepam. INHALATION SEDATION The discovery of nitrous oxide and its use in dentistry predates oral anxiolytic medications [41]. The inhalation of 100% nitrous oxide can lead to hypoxia and death; therefore, it is combined with oxygen in modern delivery systems. Nitrous oxide/oxygen can cause relaxation of the facial musculature, which can have the semblance of a grin or smile, hence the term “laughing gas.” This popular phrase may suggest a benign substance without any adverse effects, but it is an inhaled drug and all patients should be monitored carefully while it is administered. Individuals who have abused this drug for recreational purposes have developed serious health problems, including death. All clinicians who use nitrous oxide/oxygen as an anxiolytic for apprehensive patients should be trained in its use, contraindications, potential adverse effects, and appropriate monitoring procedures. Nitrous oxide/oxygen combination can be used as a single anxiolytic agent or may be combined with oral anxiolytic medications. The use of combined oral medications and nitrous oxide/oxygen is governed by various state regulations pertaining to mandatory training, emergency preparedness requirements, maximum doses, and the age of the patient. Nitrous oxide/oxygen decreases pain, anxiety, and the memory of the dental treatment. It does not replace a local anesthetic, but it can relax a patient so he or she is more receptive to it. The onset of action can begin in as little as 30 seconds, with the peak effect occurring in about five minutes. Upon completion of the dental procedure, delivery of 100% oxygen for five min- utes eliminates the nitrous oxide from the body. As opposed to oral anxiolytic medications, nitrous oxide/oxygen is not metabolized by the body [42]. Modern delivery units include a flowmeter that will stop the flow of nitrous oxide if the ratio of nitrous oxide to oxygen exceeds 70%/30% as a safeguard to prevent hypoxia [43]. The exact ratio can be customized to the needs of the patient, with the concentration of nitrous oxide usually ranging from 25% to 50%. There are relatively few side effects from nitrous oxide/oxygen sedation, with nausea and vomiting being the most common. Absolute contraindica- tions for the use of nitrous oxide/oxygen include emphysema, pneumothorax, middle ear surgery, and an air embolus [44]. The use of nitrous oxide/oxygen in pregnant patients has been controversial. Short-term use at low concentrations may
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