Oral administration route fentanyl

The availability of new routes of administration have led to increased utility and decreased opioid adverse drug reaction risk. Epidural and intrathecal administration through spinal catheters produces adequate regional analgesia at relatively low total doses compared with intravenous or oral routes. As such, spinal administration can thus minimize somnolence, nausea, vomiting, and respiratory depression associated with these medications. Other alternative routes include intranasal administration of butorphanol, and rectal and transdermal administration of fentanyl [28]. Availability of such options provides not only a decreased risk of adverse reactions, but also more comfortable measures for patients who would otherwise require continued intravenous administration, or for those who are unable to receive oral medication [28,29]. 

Opioids maybe administered in a variety of routes including oral (tablet and liquid), sublingual, rectal, transdermal, transmucosal, intravenous, subcutaneous, and intraspinal. While the oral and transdermal routes are most common, the method of administration is based on patient needs (severity of pain) and characteristics (swallowing difficulty and preference). Oral opioids have an onset of effect of 45 minutes, so intravenous or subcutaneous administration maybe preferred if more rapid relief is desired. Intramuscular injections are not recommended because of pain at the injection site and wide fluctuations in drug absorption and peak plasma concentrations achieved. More invasive routes of administration such as PCA and intraspinal (epidural and intrathecal) are primarily used postoperatively, but may also be used in refractory chronic pain situations. PCA delivers a self-administered dose via an infusion pump with a preprogrammed dose, minimum dosing interval, and maximum hourly dose. Morphine, fentanyl, and hydromorphone are commonly administered via PCA pumps by the intravenous route, but less frequently by the subcutaneous or epidural route. 

If disturbances of gastrointestinal function prevent the use of oral sustained-release morphine, the fentanyl transdermal system (fentanyl patch) can be used over long periods. Furthermore, buccal transmucosal fentanyl can be used for short episodes of breakthrough pain (see Alternative Routes of Administration). Administration of strong opioids by nasal insufflation has been shown to be efficacious, and nasal preparations are now available in some countries. Approval of such formulations in the USA is growing. In addition, stimulant drugs such as the amphetamines have been shown to enhance the analgesic actions of the opioids and thus may be very useful adjuncts in the patient with chronic pain. 

Dosages and routes of administration For acute (postoperative) pain and for anesthesia, fentanyl is given by the intravenous route. For pre-medication in anesthesia and for break-through pain the compound can also been given as an oral-transmucosal formulation (Ashburn and Streisand, 1994). A transdermal patch has been developed for chronic pain treatment (Jeal and Benfield, 1997 O Siordin, 1998). The intravenous doses for premedication are 50-100 pg, oral-transmucosal systems contain 200-400 pg and patch formulations have a delivery rate of 25-100 pg/h. 

The more novel routes of administration of opioids, including oral, nasal, rectal, transdermal, spinal, and by patient-controlled methods, have been outlined (SEDA-17, 78). Oral transmucosal fentanyl administration, avoiding first-pass metabolism, produces analgesia and sedation in both adults and children undergoing short, painful outpatient procedures. The quality of analgesia is good, and the adverse effects are those typical of the opioids. 

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