In: Anesthesia25 Jan 2010
Oral transmucosal fentanyl citrate (OTFC) is a formulation of fentanyl citrate embedded in a sweetened matrix that dissolves in a child’s mouth. The product, marketed as a lozenge attached to a plastic holder (Fentanyl Oralet; Abbott Laboratories, Abbott Park, П1), offers pediatric patients a palatable alternative to the parenteral administration of preanesthetic sedatives. Saliva dissolves the lozenge, releasing the drug for absorption across the oral mucosa. The highly vascularized mucosal tissue of the mouth has a large surface area, permitting rapid absorption of lipophilic drugs such as fentanyl. This transmucosal route of drug administration is advantageous for many drugs because it avoids first-pass metabolism. In adults, about 25% of the dissolved fentanyl citrate is taken up through the oral mucosa and directly enters the systemic circulation, bypassing the liver. However, approximately 75% of the dose is swallowed. Two thirds of this swallowed amount (about 50% of the total dose) is either metabolized or not absorbed. About one third (or about 25% of the total dose) is absorbed into the blood stream via the gut. Therefore, total fentanyl bioavailability is about 50%, with 25% through the oral mucosa and 25% through the gut. It has been reported that bioavailability may be somewhat less in children.
In children, a single dose of 10-20 ixgAg (a mean value of 16.5 |xgAg) of OTFC has been reported to result in a mean peak plasma fentanyl concentration of about 2 ng/ml 20 minutes after administration. Peak plasma levels have been shown to increase with increasing dose. Furthermore, peak concentrations are delayed following longer consumption times (the total time required to consume the lozenge dosage form). Clinical onset times for sedation and analgesia range from 5 to 20 minutes.
Oral transmucosal fentanyl citrate has been found to be an effective sedative and analgesic, providing convenient and atraumatic sedation of children prior to general anesthesia or painful diagnostic procedures. Dose-dependent side effects, including nausea, vomiting, and potentially lethal hypoventilation, can occur. When used prior to outpatient anesthesia, OTFC requires careful monitoring to prevent central nervous system (CNS) and respiratory depression. Its use is restricted to hospital and outpatient services that are appropriately staffed by trained anesthesia personnel. Use in private dental offices, where practitioner training and monitoring may be inadequate, is not advocated. Previous experience and research at the University of Pittsburgh School of Dental Medicine and Pittsburgh Children’s Hospital Dental Clinic have shown that the opioids meperidine and alphaprodine are safe and effective premedicants for pediatric dental procedures only when proper doses are administered and appropriate monitoring is provided.
The associated risks, precautions, and warnings for OTFC are those clinically associated with all opioids, including hypoventilation that may range from a mild decrease in respiratory rate to apnea. Elevated blood pressure in patients with and without preexisting hypertension has been reported following administration of fentanyl citrate combined with droperidol. Practitioners must be aware of the potential for orthostatic hypotension in the ambulatory setting and exercise care when positioning patients preoperatively, intraoperatively, and postoperatively. Fluid status prior to discharge should be evaluated. canadian pharmacy cialis
Fentanyl may also produce bradycardia that may require treatment with an anticholinergic agent. The manufacturer does not recommend the use of OTFC for patients who have received monoamine oxidase inhibitors (MAO-Is) within the last 14 days. Although some authors have found fentanyl to be safe when given intravenously to patients taking MAO-Is, severe and unpredictable potentiation by MAO inhibitors has been reported with narcotic analgesics. Elderly patients, nursing or pregnant mothers, and patients compromised by cardiovascular, respiratory, renal, and hepatic dysfunctions should be administered opioids with caution.
The specific aims of this study were (1) to determine if OTFC administered prior to outpatient general anesthesia would provide sedation and improvement in the level of cooperation for induction of general anesthesia, (2) to determine if OTFC increased side effects and complications associated with the anesthetic procedure, and (3) to determine if OTFC delayed the time required for recovery and discharge following anesthesia.
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