Medications fat-soluble

Physiological changes owing to the aging process will result in an increase in lipid mass and a decrease in lean body mass. Fat-soluble medications may distribute more widely and remain in the body longer in an elderly patient, whereas water-soluble medications have a smaller volume of distribution because of decreased lean mass. 

Certain fat-soluble medications, such as chloral hydrate, may depress the melting point when incorporated into a base. Similarly, when large amounts of an active substance, either solid or liquid, have to be dispersed into a base, the rheological characteristics of the resultant suppository may be changed, with concomitant effects on release and absorption. Careful selection of bases or the inclusion of additives may therefore be necessary. 

Tissue-binding Tissue-binding occurs when medication binds to tissues, such as fat-soluble medication binding to adipose tissues. 

Medications metabolized by the liver are secreted into bile. Bile enters the intestine and is eliminated in feces. Fat-soluble medications are reabsorbed from bile into the bloodstream and returned to the liver to be metabolized and eliminated by the kidneys. This process is called the enterohepatic cycle. Medications that are not metabolized by the liver are eliminated by the lungs at a rate that corresponds to the patient s respiration rate. These are volatile medications, such as anesthetics and medications that are metabolized to C02 and H20. Side effects such as rashes and skin reaction are commonly seen at sweat and salivary glands. For example, a patient may report tasting the medication. Medication excreted into saliva is eventually swallowed, reabsorbed, and... 

Cholestyramine use is not without limitations. It does not bind chlordecone alcohol, a metabolite of chlordecone that is also excreted in the bile (Guzelian 1981). It has a gritty texture in the mouth, and it causes several gastrointestinal disturbances, which may limit the willingness of patients to take it. It may also interfere with the absorption of fat-soluble vitamins and interact with other medications (Goldfrank 1990). 

Covalent compounds are generally insoluble in water. This is shown by the fact that our proteins, skin and cell materials do not dissolve in the rain Covalent compounds can dissolve in other covalent liquids like oils or fats. Thus the effectiveness of any medication containing covalent or ionic molecules depends upon their solubility, the type of molecules present in the drug, and the parts of the cells being targeted. Some medications are water-soluble (usually containing ions) while others are fat-soluble (usually containing covalent molecules). 

Solubility Medication particles dissolve in either lipid (fat) or water. Lipid soluble medication absorbs faster than water-soluble medication because membranes in the GI tract are composed of lipids and can directly transport particles into the bloodstream. Water-soluble medications must use an enzyme or protein carriers to be transported across the GI membrane and into the bloodstream, which influences the absorption rate. 

The use of antioxidants in human-contact applications, e.g., food-contact, medical, and pharmaceutical, present a challenge in terms of their safety and level of migration into the contact media, e.g., food and body fluids. The biological antioxidant vitamin E, which is a suitable candidate for such areas of application, is a fat-soluble, and sterically hindered phenol antioxidant with the most bioactive form of the vitamin being the a-tocopherol (Table 1, AO 10). 

Cholestyramine is another treatment option for cholestasis of pregnancy. It is an oral medication that binds bile salts in the intestine and promotes their excretion in the feces. As this drug is not absorbed, it most likely has little effect on the fetus. Effects on the fetus are stiU under evaluation. However, cholestyramine can interfere with the absorption of fat soluble vitamins, such as vitamins A, D, E, and K. In rare cases, drug-induced vitamin K deficiency is believed to contribute to hemorrhaging during childbirth. 

Colestipol causes constipation and a bloating sensation. The absorption of fat-soluble vitamins and certain drugs such as digitalis, thiazides, tetracycline, and phenylbutazone may be altered. Therefore, medications are given either 1 hour before or 2 hours after colestipol. 

To help prevent vitamin D deficiency, most milk is now enriched with it. Other good sources of the vitamin are meat, poultry, fish, peanut butter, eggs, margarine, and liver, especially cod-liver oil. These sources exist in addition to the vitamin D produced naturally from exposure to sunshine. Unlike water-soluble vitamins, such as vitamin C, fat-soluble vitamins are stored in the liver and fat tissue and can become highly toxic if taken in excess. For these reasons, most nutrition experts do not generally recommend additional dietary supplements for vitamin D. Some individuals taking special medication for cholesterol, or who have dark sldn (which reduces the ability of sunshine to produce vitamin D), may require a diet rich in vitamin D or a supplement, see also Calcium Cholesterol. 

Vitamin A supplements in pill or capsule form are available in two formulations, those that contain retinol and those that contain beta carotene. It is not possible to take too much of the latter type of vitamin A. The body will not convert excess amounts of carotene into retinol hut will, instead, excrete the excess in the urine or stool. An excess of retinol-based vitamin A, hy contrast, may result in certain medical problems. Since the vitamin is fat soluble, in may he stored in body fat and reach relatively high concentrations if too much is ingested. An excess of retinol in the body may he associated with liver damage, osteoporosis, rash, fatigue, hone and joint pain, nausea, insomnia, and personality changes. 

What should be considered in the elution of DEHP from PVC medical devices are fat-soluble agents and blood products into which DEHP may be eluted at high concentrations. The amount of DEHP that eluted into blood products stored in PVC bags was measured. When the amounts of DEHP in red blood cell products, whole blood products, blood platelet products, and blood plasma products were compared, a high concentration of DEHP was detected in whole blood products. This means that the sample matrix affects the elution of DEHP. We also analyzed blood products stored in PVC bags and found that the amount of DEHP eluted increased with the storage period, and the exposure to DEHP in an amount that exceeded tolerable dairy intake (TDI) value was noted after only one blood transfusion even if the blood product had not reached the expiration date. In addition, we established a method for the simultaneous analysis of DEHP and MEHP with high sensitivity and accuracy and... 

Liver Chemical Processing. For protection from dangerous accumulation of various toxins, the body has evolved methods to eliminate foreign substances. Potentially harmful chemicals can originate from myriad sources including foods, liquids, air, and, of course, medications. The liver s role is to inactivate these chemicals and to convert (metabolize) them to water-soluble forms (i.e., forms that dissolve in water rather than fat), which can more easily be filtered and eliminated by the kidneys. 

Since the discovery of synthetic dye by Perkin and the establishment of the synthetic organic chemistry industry, a wide variety of synthetic dyes provided a set of choices for staining microbes so that they could be readily examined under the microscope. It is reasonable to suppose that if a dye binds selectively to a microbe much more than to mammalian tissues, then it may be possible to find a dye that selectively harms the microbe and spares the mammal. Paul Ehrlich (figure 1.6) was a medical student who did research in the distribuhon of foreign substances in the body, and he was particularly interested in the influence of chemical structures of different types of molecule in live animals. He observed that acidic dyes with the sulfonic acid function, used by dye manufacturers to enhance water solubility, were unable to penetrate into the brain or fat tissues. 

Most psychotropic medications are highly lipophilic. The percentage of total body fat, which is a reservoir for these lipid-soluble compounds, increases during the first year of life and then decreases until the prepubertal increase ( 30). Thus, children at different ages have different volumes of deep storage, which can affect the overall residual time a drug remains in the body after its discontinuation. 

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