Influence of fluid zapivaniya the absorption and bioavailability of drugs
The amount and quality of liquid zapivaniya, patients received simultaneously with the drug, It can have a significant impact on its efficiency by changing the kinetics absorption and bioavailability. Experimentally proved, that for many drugs taken orally acidic or basic character bioavailability equal doses from a dilute solution compared with the above concentrated. This phenomenon, seemingly anomalous, It explained more rapid emptying of stomach contents, It caused a large number of liquid, adopted simultaneously with the drug. This pattern is observed for acetylsalicylic acid, barbital-sodium, particularly theophylline and erythromycin, whose solubility in water is significantly lower, and use it with a large amount of water causes an increase in the bioavailability of the antibiotic. In other words, the absorption of the drug is directly dependent on its solubility in water. Increasing the amount of water 25 to 250 ml causes significant increase in the bioavailability of amoxicillin, less impact on the absorption of ampicillin and virtually no effect on absorption of doxycycline and tetracycline.
The use of mineral water has long been known in the pharmacotherapy. However, to achieve efficacy and safety of their reception is possible only on the basis of physical and chemical properties of mineral waters and Medicine, used simultaneously. For Example, alkaline mineral water it is advisable to drink sulfonamides, that body subjected to acetylation and metabolic products which are in the neutral and acidic medium insoluble, that can promote the formation of salts and acids. In an alkaline environment, the acetylated sulfonamides are readily dissolved and removed from the body. However, alkaline water can not drink medicines with acid-resistant coatings.
If the medicine is not washed down with water, and the other liquid, it is necessary to take into account its qualitative composition. So, eg, in tea and coffee contain caffeine, which may change the absorption of ergotamine (by increasing its solubility and thereby enhance the acidity of gastric contents). Slows absorption of antipsychotics (haloperidol, propafenone, chlorpromazine) due to their precipitation when mixed with tea and coffee. Coffee facilitates the rapid removal of ampicillin and other substances from the body, are excreted in the urine by filtration; increases the concentration of theophylline in plasma and slows its catabolism in the liver. Some drugs interact actively with caffeine, theophylline, tannins, contained in these drinks. So, Caffeine potentiates the analgesic effect of paracetamol and aspirin. When using barbiturates (ʙarʙitala, fenoʙarʙitala) It recommended to drink a glass of warm weak tea for better absorption and gain passage through the blood-brain barrier of sleeping pills. The strong brewed tea and boiled a lot of tannins, that form sparingly soluble compounds with chlorpromazine, haloperidol, Morphine preparations, codeine, atropyna (It is used in cases of poisoning with these drugs). When combined oral contraceptives with tea (caffeine) there may be minor mental disorders, and by reacting xanthine derivatives with monoamine oxidase inhibitors, some patients may headache, and increased blood pressure.
When zapivaniya medicines tonics ("Pepsi-Cola", Coke, "Baikal"), Multivitamin drink ("Zhivchik") and soft drinks should be considered in the presence of some of them of iron ions, which can form insoluble complexes in the gastrointestinal tract with tetracycline, oleandomiцina fosfatom, lincomycin hydrochloride other drugs, which leads to a marked decrease of their absorption in the digestive tract.
Ambiguous effect of fruit juices and syrups on the kinetics of absorption of drugs when they are used simultaneously. Cherry and currant berry juice slow the absorption of ibuprofen, izoniazida, calcium chloride, metamizola, tetracycline, fenilʙutazona, furosemida. Acidic fruit and vegetable juices significantly reduce the effectiveness of ampicillin, cyclosporine, erythromycin and, conversely, enhance the effect of acetazolamide, ʙarʙituratov, ʙuformina, nalidixic acid, nitrofuran, salicylic acid derivatives. Not recommended fruit and berry juice drink acid-unstable antibiotics (eg, Erythromycin). Many fruit juices are deposited digitoksin, Caffeine-sodium benzoate.
The unique properties has grapefruit juice. It can improve the oral absorption of certain drugs, protease inhibitors, such as HIV-1 or the calcium channel blockers. Noticeable effect of grapefruit juice on the bioavailability of the calcium antagonist felodipine (by inhibiting presystemic metabolism) observed in 30-38% patients. This phenomenon is explained by the fact, that grapefruit juice nnak- tiviruet major enzyme intestinal CYP-ZA4, protecting the drug from premature destruction. However juice activates P-glycoprotein, which "beats" of the molecule of the drug from the wall back into the gut lumen and thereby adversely affect the absorption vinblastine, cyclosporine, losartan potassium, digoxin and geksofenadina.
Given the ability to vary the concentration of the juice of drugs in the body, It recommended to drink it for 2 hours to take medicine. At this time, grapefruit juice will optimally show their positive characteristics: the effect of the actions of P-glycoprotein will be minimal, and the positive effect of the suppression of CYP-ZA4 will still be in force.
Sugar syrups slow down the absorption of ibuprofen, furosemida, Erythromycin, Ampicillin, cycloserine and other medicinal substances.
At zapivaniya drugs milk also need to take into account some special features. One side, milk it is advisable to wash down medicines, which irritate the gastrointestinal mucosa, but only if, that they do not bind to proteins, magnesium and calcium this product, and do not change their activity at pH milk (6,4). It is a non-steroidal anti-inflammatory agents, prednisolone and other.
On the other hand, is present in milk reduces the absorption of calcium caseinate tetracyclines due to the formation of chelate compounds. So, upon administration of tetracycline in optimal conditions, its concentration in the blood is through 1,5 o'clock - 1,8 ug / ml, through 3 o'clock - 3,7 ug / ml, and through 6 hours - 4,0 ug / ml. After the use of antibiotics at the same time with a glass of milk in the plasma concentration of the antibiotic is much lower - 0,8, 1,6 and 1,3 ug / ml, respectively. Reduced and therapeutic efficacy of tetracycline. Whole milk gives a more pronounced results, than dairy products. Glass whole milk reduces the concentration of tetracycline and oxytetracycline in the blood 50-60%; less affected by the absorption of doxycycline. Calcium, contained in milk, associates around 40% caffeine. Therefore, tea or coffee with milk practically devoid of stimulating effects of caffeine.
Milk low fat connection in people - "slow acetylators", It reduces the bioavailability of isoniazid and does not affect the rate in humans - "fast acetylators". When taken with milk bisacodyl, pancreatin, calcium there is a risk of premature their cleavage. Therefore, do not drink milk, medicines with acid-resistant coating (pancreatin, bisacodyl et al.), since soluble protective shell and the substance is destroyed, reaching under suction space. The presence of lipids in the milk promotes rapid dissolution of the fat-soluble drug, but slows dissolution of substances with a high ratio of oil / water. Often drugs, which give children, mixed with milk in a bottle with a nipple, reducing the intended dose of the drug due to interactions with the components of milk. Besides, milk can modify the active substances, reducing their bioavailability (cephalexin, penicillins). The milk does not affect the bioavailability of doxycycline, but significantly increases its clearance (from 39,7 to 61,0 ml / min.).
Interactions of dairy products with tetracyclines, lincomycins gidrohloridom, and antacid, antidiarrheal and iron supplements can be avoided, increase the distance between their methods up to 3 hours.
Thus, we can recommend most drugs drink water, better boiled, in an amount 100 milliliters.
