Renal excretion pharmacological activity

Biotransformation involves the chemical alteration of a molecule to alter its effects. This often terminates the pharmacological effects of a drug, but active metabolites are produced in some cases. Biotransformation also changes the ease with which a drug is eliminated. This involves conversion of the drug to a more hydrophilic metabolite that enhances renal excretion. Although this process pertains to most drugs, it probably... 

The ultimate disposition of minoxidU depends primarily on hepatic metabolism and only slightly on renal excretion of unchanged drug. Because of this, pharmacological activity is not cumulative in patients with renal failure. 

Clonidine is well absorbed after oral administration. Peak plasma levels occur between 2 and 4 hours after drug administration and correlate well with pharmacological activity. The plasma half-life in patients with normal renal function is 12 hours. Urinary excretion of clonidine and its metabolites accounts for almost 90% of the administered dose, and fecal excretion accounts for the rest. Approximately 50% of an administered dose is excreted unchanged the remainder is oxidatively metabolized in the liver. 

Most drugs are not excreted unchanged by the kidneys but first are biotransformed to metabolites that then are excreted. Renal failure not only may retard the excretion of these metabolites, which in some cases have important pharmacologic activity, but, in some cases, alters the nonrenal as well as the renal metabolic clearance of drugs (15, 24). The impact of impaired renal function on drug metabolism is dependent on the metabolic pathway, as indicated in Table 5.2. In most... 

Pethidine is extensively metabolised in the liver and the parent drug and metabolites are excreted in the urine (t) 5 h). Norpethidine retains pharmacological activity and may accumulate dangerously when renal function is impaired. 

Many drugs and their metabolites are excreted via the kidneys. The most important clinical implications of altering renal excretion involve the use of drugs that are excreted in their unchanged form or in the form of an active metabolite. Thus, substances with pharmacological activity are being reabsorbed or excreted to a greater extent when renal excretion is altered. 

The main role of the kidney in the process of drug metabolism consists in the excretion of the many, more or less pharmacologically active metabolites formed in the liver [8]. Needles to say that renal insufficiency may result in the accumulation of metabohtes and, if pharmacological active, may result in serious side effects/ toxicity [33]. Renal metabolism of drug-xenobiotics and its contribution to elimination has been inadequately explored so that clinical implications are for the most part inferred from animal models or speculative. 

Excretion of drugs or chemicals from the body can occur through biliary, intestinal, puhnonary, or renal routes. Although each of these represents a possible mechanism of drug elimination, renal excretion is a major pathway for the ehmination of most water-soluble drugs or metabohtes and is important m TDM. Alterations in renal function may have a profound effect on the clearance and apparent half-life of the parent compound or its active metabolite(s) decreased renal function causes elevated serum drug concentrations and increases the pharmacological response. 

After oral administration, eslicarbazepine is quickly and extensively hydrolysed to the pharmacologically active agent, S -licarbazepine, with maximum observed plasma concentrations at 1-4 hours. The half-life at steady state is 20-24 hours, compatible with once-daily administration [144 ]. Glucuronidation and renal excretion are the main metabolic pathways of elimination. Eslicarbazepine has linear pharmacokinetics across a dose range of 400-2400 mg/day and does not seem to induce or inhibit P450 enzymes, in... 

Lidocaine undergoes primarily (>90%) hepatic metabolism via CYP3A4 and CYPl A2 enzymes to the pharmacologically active metabolite monoethylglycinexyhdide, the majority of which is hepatically converted to the inactive metabolite glycinexylidide. Both metabolites are renally excreted, so adverse side effects from metabolite accumulation may present in patients with renal failure, despite normal serum lidocaine levels. Its elimination half-life ranges from 1 to 1.5 hours in... 

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