phase I See clinical trial. phase II See clinical trial.
phase III See clinical trial.
phase IV See clinical trial.
phenindamine An antihistamine used to temporarily relieve runny nose, sneezing, itching of the nose or throat, and itchy, watery eyes due to hay fever or other upper respiratory allergies. In people with HIV, the drug is also used to reduce certain drug-induced allergic side effects, including skin rashes, swelling, hives, and breathing difficulties. Drowsiness is the most common side effect; less often, dry mouth, nervousness, insomnia, and increased irritability or excitement may occur. Available over the counter in tablets. (Trade name is Nolahist.)
phenotype An organism's functional capabilities and outward appearance. It is the physical expression of the genotype. Also the trait or behavior that results from changes in genotype, for example, the ability of the virus to replicate in the presence of a drug, compared with a drug-sensitive control virus or wild-type nonmutant HIV. See genotype.
phenotypic assay A virus culture-drug test that measures some aspect of an organism's functions, for example, the amount of a certain drug needed to inhibit the growth of an HIV isolate in a test tube culture. If HIV has developed resistance to a certain drug, higher than normally administered amounts of that drug are necessary to inhibit viral activity. Resistance is characterized as high-level, intermediate-, or low-level. Note that interpretation is not standard and that the standard deviation is considerable on both this and genotypic assay resistance testing. Phenosense and Antivirogram are commercially available in the United States. Phenotype testing is very expensive; because of this and the time element (about two to five weeks for results), such testing is not readily available. Thus, patients rely on the cheaper and faster (one week) geno-typic testing. Most third-party payers do not cover these tests. See genotypic assay.
phone zap A technique used by AIDS activists and others to bring pressure on a corporation,
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