Meloxicam has been shown, especially at low therapeutic doses, to selectively inhibit COX-2 over COX-1.Meloxicam concentrations in synovial fluid range from 40% to 50% of those in plasma. The free fraction in synovial fluid is 2.5 times higher than in plasma, due to the lower albumin content in synovial fluid as compared to plasma. The significance of this penetration is unknown, but it may account for the fact that it performs exceptionally well in treatment of arthritis in animal models. Pharmacokinetics
Absorption
The bioavailability of meloxicam is decreased when administered orally compared to an equivalent IV bolus dose. Use of oral meloxicam following a high-fat breakfast increases the mean peak drug levels by about 22%; however, the manufacturer does not make any specific meal recommendations. In addition, the use of antacids does not show pharmacokinetic interactions. Distribution
The mean volume of distribution of meloxicam is approximately 10L. It is highly protein-bound, mainly to albumin. Metabolism
Meloxicam is extensively metabolized in the liver by the enzymes CYP2C9 and CYP3A4 (minor) into four inactive metabolites. Peroxidase activity is thought to be responsible for the other two remaining metabolites. Excretion
Meloxicam is predominantly excreted in the form of metabolites and occurs to equal extents in the urine and feces. Traces of unchanged parent drug are found in urine and feces. The mean elimination half-life ranges from 15 to 20 hours. Specific populations
Geriatrics
Use of meloxicam is not recommended in people with peptic ulcer disease or increased gastrointestinal bleed risk, including those over 75 years of age or those taking medications associated with bleeding risk.
It is converted to aciclovir in the body after absorption.In 2009, acyclovir in combination with hydrocortisone cream, marketed as Xerese, was approved in the United States for the early treatment of recurrent herpes labialis (cold sores) to reduce the likelihood of ulcerative cold sores and to shorten the lesion healing time in adults and children (six years of age and older). Society and culture
Names
Aciclovir is the international nonproprietary name (INN) and British Approved Name (BAN) while acyclovir is the United States Adopted Name (USAN) and former British Approved Name.It was originally marketed as Zovirax; patents expired in the 1990s and since then it is generic and is marketed under many brand names worldwide. Notes
References
Further reading
Hazra, S; Konrad, M; Lavie, A (2010). "The sugar ring of the nucleoside is required for productive substrate positioning in the active site of human deoxycytidine kinase (dCK): Implications for the development of dCK-activated acyclic guanine analogues". Journal of Medicinal Chemistry. 53 (15): 5792–800. doi:10.1021/jm1005379. PMC 2936711. PMID 20684612. Harvey Stewart C. in Remingtons Pharmaceutical Sciences 18th edition: (ed. Gennard, Alfonso R.)  Mack Publishing Company, 1990. ISBN 0-912734-04-3. Huovinen P., Valtonen V. in Kliininen Farmakologia (ed. Neuvonen et al.). Kandidaattikustannus Oy, 1994. ISBN 951-8951-09-8. Périgaud C.; Gosselin G.; Imbach J.-L. (1992). "Nucleoside analogues as chemotherapeutic agents: a review". Nucleosides and Nucleotides. 11 (2–4): 903–945. doi:10.1080/07328319208021748. Rang H.P., Dale M.M., Ritter J.M. : Pharmacology, 3rd edition. Pearson Professional Ltd, 1995. 2003 (5th) edition ISBN 0-443-07145-4; 2001 (4th) edition ISBN 0-443-06574-8; 1990 edition ISBN 0-443-03407-9. External links
"Acyclovir". Drug Information Portal.