Drug dependence intravenous fluid

The therapeutic range and risks associated with under- and overinfusion are highly drug and patient dependent. Intravenous delivery of fluids and electrolytes often does not require very accurate regulation. Low-risk patients can generally tolerate well infusion rate variability of 30% for fluids. In some situations, however, specifically for fluid-restricted patients, prolonged under- or overinfusion of fluids can compromise the patient s cardiovascular and renal systems. 

Absorption is the transfer of a drug from its site of administration to the blood stream. The rate and efficiency of absorption depend on the route of administration. For intravenous delivery, absorption is complete, that is, the total dose of drug reaches the systemic circulation. Drug delivery by other routes may result in only partial absorption and thus lower bioavailability. For example, the oral route requires that a drug dissolve in the gastrointestinal fluid and then penetrate the epithelial cells of the intestinal mucosa disease states or the presence of food may affect this process. 

The aqueous solubility of a drug in the 2-8 pH range has a direct influence on its oral and parenteral formulations. A drug with poor solubility (i.e., less than O.lmg/ml) in acidic media may show poor and erratic oral bioavailability due to the dependency of absorption processes in GI fluids. Intravenous dosing requires that the drug be administered in a soluble form. The adjustment of pH, the addition of a cosolvent or a ligand for complexation, or the formation of an emulsion may permit solubilization, but each of these techniques has limitations. Rapid intravenous... 

In Equation 17.22, the body is considered as a single homogeneous pool of body fluids as described above for digoxin. For most drugs, however, two or three distinct pools of distribution space appear to exist. This condition results in a time-dependent decrease in the measurable blood or plasma concentration, which reflects distribution into other bod pools independent of the body s ability to eliminate the drug. Figure 17.3 describes mean serum IFN-a concentrations after a 40-min intravenous infusion as well as after intramuscular and subcutaneous injections of the same dose. Note the logarithmic biphasic nature of the mean plasma concentration-time curve after the intravenous infusion. This biphasic nature represents both the distribution and elimination processes. 

An important feature of drug development is the estimation of pharmacokinetic parameters in animal models. Pharmacokinetics is the study of the time dependence and mechanism of absorption of a compound dosed into the body, its distribution throughout the fluids and other body tissues, the sequential metabolic transformations of the compound and its first-generation metabolites, and the elimination of the original compound and its metabolites (whence the common abbreviation ADME studies). The usual experimental raw data consist of concentrations of the test compound (and sometimes of its metabolites) in body tissues and body fluids (blood plasma, urine) as a function of time following a single dose. Extraction of quantitative parameters characterizing this behavior is determined by the theoretical model used to interpret the data. For example, if the dose is administered intravenously and the compound concentrations are measured in the blood, there will be an immediate drop of compound concentration with time as the compound is re-distributed, metabolized and excreted, but if an oral dose is used (as... 

The ability to carry out some routine medical interventions, such as intravenous access and advanced airway management, is usually attenuated by PPE. In this case, intraosseous access may be a more appropriate and dependable mode for the administration of drugs or fluids for resuscitation. The use of a laryngeal mask airway (LMA) may temporise an otherwise unprotected airway in an unconscious patient until that casualty can be extricated, decontaminated and moved safely into the cold zone. 

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