first-pass effect

first-pass metabolism

the intestinal and hepatic degradation or alteration of a drug or substance taken by mouth, after absorption, removing some of the active substance from the blood before it enters the general circulation.
Synonym(s): first-pass effect

first-pass me·tab·o·lism

, first-pass effect (fĭrst-pas mĕ-tab'ŏ-lizm, e-fekt')
The intestinal and hepatic degradation or alteration of a drug or substance taken by mouth, after absorption, removing some of the active substance from the blood before it enters the general circulation.
References in periodicals archive ?
The h-Patch system provides a continuous basal delivery rate over a period of 24 hours, and maximizes therapeutic effect by avoiding the first-pass effect and eliminating peak/trough variations of drug exposure.The Company believes subcutaneous infusion of CBD via the h-Patch may offer several distinct advantages over oral dosing including the ability to achieve therapeutic drug concentrations with a fraction of the overall dose, significantly prolonged half life, minimization of the variation in CBD metabolism in the general population, and a dramatic reduction in the overall amount of drug metabolized by the liver.
Drugs that are degradable in the gastro intestinal (GI) tract or hepatic first-pass effect that inactivates them are proper candidates for transdermal drug delivery [17].
At the beginning, consciousness of the patient is impaired because of a first-pass effect through the brain following its intravenous injection.
Systemic THC levels and psychoactive effects after ingestion are highly variable because of differences in bioavailability, rate of gastrointestinal absorption, and metabolic first-pass effect whereby an orally administered drug is partially metabolized (principally in the liver) before reaching systemic distribution (6,7).
In the vaginal method, intestinal - gastric medicine absorption and hepatic first-pass effect are eliminated.
This high systemic bio availability was confirmed by the mean ratio of BPAG AUC values (81 [+ or -] 18% for sublingual dosing), which is also an estimate of the systemic bioavailability, provided that the BPAG is not formed at the administration site or by a first-pass effect, which seems to be a reasonable assumption for a direct buccal absorption.
Food and Drug Administration approved dose of 10 mg has little effect on nasal decongestion when used orally because of the drug's high first-pass effect. This agent is common under the name PE, for example Sudafed PE.
Due to the 'uterine first-pass effect', hormones concentrate in the uterus and nearby tissues with low systemic exposure.
Because of the hepatic first-pass effect, 1 mg of oral 17[beta]-estradiol and 25 [micro]g of transdermal estrogen yield equivalent levels of free serum estradiol.
When taken orally, selegiine has a very high first-pass effect; this is circumvented with the transdermal formulation, resulting in sustained plasma levels and 50 times more of the parent compound, and far fewer metabolites, in the body, he said.
When taken orally selegiline has a very high first-pass effect; this is circumvented with the transdermal formulation, resulting in sustained plasma levels and 50 times more of the parent compound, and far fewer metabolites, in the body, he said.

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