Centrifugation: When plasma is required, or when not using a serum gel separator tube, follow these instructions: 1  Draw 12 mL of whole blood for each 5 mL of serum or plasma needed. 2  Centrifuge for at least 15 minutes at 2200-2500 RPM. 3  Pipette the serum or plasma into a clean plastic screw-cap vial and attach the label.
Buccal administration; Naloxone; Naltrexone; opioid antagonist; Pharmacokinetics; First-pass metabolism Summary The opioid antagonists naloxone and naltrexone are both known to undergo extensive first-pass metabolism after oral dosing. The buccal route was investigated as a potential alternative to oral administration. Oral and buccal bioavailabilities of naloxone and naltrexone were determined in rats. Less than 1 % of oral naloxone or naltrexone was bioavailable, but buccal administration resulted in approximately 70% bioavailability for each drug.
Oral Naltrexone: If it's taken at home, the drug is usually taken once a day with or without food. If it's taken at a treatment center, naltrexone can be administered once a day, once every other day, once every third day, or once every day. The typical dose of naltrexone is 50 milligrams (mg) a day.If it's given in a clinic setting, your health care provider may put you on a higher dose (up to 150 mg) to be taken on different days. You can take this medicine with or without food.19 Reviews. Naltrexone is the generic form of the brand-name drug Vivitrol, which is used to prevent substance abuse in people who have been addicted to alcohol or opioid pain medications. Examples of opioid painkillers include Norco (hydrocodone/acetaminophen), OxyContin (oxycodone), and codeine.