Foods Doxycycline

Tetracyclines. It is important to give the tetracyclines on an empty stomach tetracyclines are not to be taken with dairy products (milk or cheese). The exceptions are doxycycline (Vibramycin) and minocycline (Minocin), which may be taken with dairy products or food. The nurse should give clindamycin with food or a full glass of water. The nurse can give troleandomycin and clarithromycin without regard to meals. All tetracyclines should be given with a full glass of water (240 mL). 

Doxycycline Tablets, capsules 50, 1 00 mg 1 00-200 mg daily before meals Maintenance dose 50 mg daily Gl upset, phototoxicity, drug and food interactions... 

Doxycycline is commonly used for moderate to severe acne vulgaris. It is more effective and produces less resistance than tetracycline. The initial dose is 100 or 200 mg daily, followed by 50 mg daily as a maintenance dose after improvement is seen. Doxycycline maybe given with food, but it is more effective when taken 30 minutes before meals. / Minocycline is also commonly used for moderate to severe acne vulgaris. It is more effective than tetracycline. It is dosed similar to doxycycline (100 mg/day or 50 mg twice daily) and on an indefinite basis in selected patients. Minocycline has the most reported adverse effects of the tetracyclines, some of which may be serious. 

Administration of 100 mg doxycycline, in the absence of foods, led to almost complete absorption from the gut and a peak blood level of 1-8 Mg/ml two hours after ingestion. Three times this dose was required.to produce a similar blood level in four hours in the case of 300 mg demethylchlortetracycline. The plasma half-life (after single dose) was 15 hours in the case of doxycycline and 12 hours for demethylchlortetracycline. This means that the half-life of doxycycline is seven hours longer than that of tetracycline. 

Differences in clinical effectiveness are partly due to differences in absorption, distribution and excretion of the individual drugs. In general tetracyclines are absorbed irregularly from the gastrointestinal tract and part of the dose remains in the gut and is excreted in the faeces. However this part is able to modify the intestinal flora. Absorption of the more lipophilic tetracyclines, doxycycline and minocycline is higher and can reach 90-100%. The absorption is located in the upper small intestine and is better in the absence of food. Absorption is impaired by chelation with divalent cations. In blood 40-80% of tetracyclines is protein bound. Minocycline reaches very high concentrations in tears and saliva. Tetracyclines are excreted unchanged, in both the urine by passive filtration and in the feces. Tetracyclines are concentrated in the bile via an active... 

Absorption from the gastrointestinal tract can be affected by other drugs and by food. Aluminum, calcium, and magnesium ions in antacids or dairy products form insoluble chelates with all tetracyclines and inhibit their absorption. Food inhibits tetracycline absorption but enhances doxycycline absorption food delays but does not diminish metronidazole absorption fatty food enhances griseofulvin absorption. 

These antibiotics are partially absorbed from the stomach and upper gastrointestinal tract. Food impairs absorption of all tetracyclines except doxycycline and minocycline. Absorption of doxycycline and minocy-cbne is improved with food. Since the tetracyclines form insoluble chelates with calcium (such as are found in many antacids), magnesium, and other metal ions, their simultaneous administration with milk (calcium), magnesium hydroxide, aluminum hydroxide, or iron will interfere with absorption. Because some of the tetracyclines are not completely absorbed, any drug remaining in the intestine may inhibit sensitive intestinal microorganisms and alter the normal intestinal flora. 

The absorption of tetracycline administered orally is variable and depend upon the type of tetracycline used. The tetracycline form insoluble complexes i.e. chelation with calcium, magnesium, milk and antacids reduce their absorption. Administration of iron also interferes with the absorption of tetracycline. Doxycycline is rapidly and virtually completely absorbed after oral administration and its absorption is not affected by presence of food or milk. 

Tetracyclines mainly differ in their absorption after oral administration and their elimination. Absorption after oral administration is approximately 30% for chlortetracycline 60-70% for tetracycline, oxytetracycline, demeclocycline, and methacycline and 95-100% for doxycycline and minocycline. Tigecycline is poorly absorbed orally and must be administered intravenously. A portion of an orally administered dose of tetracycline remains in the gut lumen, modifies intestinal flora, and is excreted in the feces. Absorption occurs mainly in the upper small intestine and is impaired by food (except doxycycline and... 

The oral dosage for rapidly excreted tetracyclines, equivalent to tetracycline hydrochloride, is 0.25-0.5 g four times daily for adults and 20-40 mg/kg/d for children (8 years of age and older). For severe systemic infections, the higher dosage is indicated, at least for the first few days. The daily dose is 600 mg for demeclocycline or methacycline, 100 mg once or twice daily for doxycycline, and 100 mg twice daily for minocycline. Doxycycline is the oral tetracycline of choice because it can be given as a once-daily dose and its absorption is not significantly affected by food. All tetracyclines chelate with metals, and none should be orally administered with milk, antacids, or ferrous sulfate. To avoid deposition in growing bones or teeth, tetracyclines should be avoided in pregnant women and children less than 8 years of age. 

Oxytetracycline (OTC), tetracycline (TC), and chlortetracycline (CTC) are the main representatives of this antibiotic class. In addition, demeclocycline (DMC), doxycycline (DXC), minocycline (MNC), and methacycline (MTC) can be found in food samples. 

Tetracyclines are recommended as first-line treatment. When tetracyclines are not tolerated or contraindicated, erythromycin is an alternative. However erythromycin has problems with resistance and gastrointestinal adverse effects. If compliance is a problem, either doxycycline or lymecycline may be prescribed (can be taken once daily with food). Minocycline is second-line treatment (e.g. if oral antibiotic has failed). 

Milk and dairy foods decrease the absorption of some tetracyclines (doxycycline and minocycline are not affected), some quinolone antibiotics (absorption of ciprofloxacin and norfloxacin is decreased but ofloxacin is not affected), penicillamine and alendronate. Large volumes of milk can reduce the ulcer-healing properties of bismuth tripotassium dicitratobismuthate (bismuth chelate),... 

In a contained casualty setting, children with inhalation anthrax can receive intravenous antibiotics in a mass casualty setting and as postexposure prophylaxis, children can receive oral antibiotics (Inglesby et al., 2002). Doxycycline is dispensed in a tablet that children may not be able to swallow however, it can be ground and mixed with food or drink to make it palatable. Palatable foods and drinks for mixing doxycycline include chocolate pudding, chocolate milk, low-fat chocolate milk, simple syrup with sour apple flavor. 

USFDA (US Food and Drug Administration) (2001). Prescription drug products doxycycline and penicillin G procaine... 

Doxycycline also requires only twice-a-day dosing and can be taken with foods, both of which enconrage patient compliance. 

The administration of tetracycline with food can ameliorate its irritative effects, bnt food can adversely affect the drug s absorption. In contrast, the absorption of doxycycline is only slightly affected by the presence of food, including dairy prodncts. Becanse all tetracyclines can form complexes with divalent cations, the absorption of any tetracycline is markedly decreased when administered with iron-containing tonics or antacids containing calcium, magnesium, or aluminum. Sodium bicarbonate also adversely affects tetracycline absorption. 

Doxycycline is well absorbed from the gut, even after food. It is excreted in the bile, in the faeces which it re-enters by diffusing across the small intestinal wall and, to some extent, in the urine (t y 16 h). These nonrenal mechanisms compensate effectively when renal function is impaired and no reduction of dose is necessary 200 mg is given on the first day, then 100 mg/d. 

The presence of food in the GI tract reduces the absorption of many antiinfective agents. Although there are some exceptions (e.g., penicillin V, amoxicillin, and doxycycline), it is generally recommended that penicillin and tetracycline derivatives, as well as certain other antiinfective agents, be given at least 1 h before meals or 2 h after meals to achieve optimum absorption. 

Doxycycline can cause nausea, vomiting, and diarrhea. The bioavailability of doxycycline is reduced if coadministered with multivalent ions such as iron or magnesium. However, unlike tetracycline, it can be administered with food and dairy products. In addition, patients taking tetracyclines may experience photosensitivity, especially if they are fair skinned. Patients taking tetracyclines should avoid prolonged exposure to sunlight. 

Drug interactions The bioavailability of tetracyclines is significantly deaeased when administered with antacids containing aluminum, calcium, or magnesium, with iron-containing products, or with food. Food or dairy products do not affect the bioavailability of doxycycline or minocycyline. 

THERAPEUTIC USES The tetracychnes have been used extensively to treat infectious diseases and as food additives in animals, leading to widespread resistance. They remain useful for infections caused by rickettsiae, mycoplasmas, and chlamydiae doxycycline is used for respiratory infections that increasingly are resistant to other drugs. 

B. Pharmacokinetics Oral absorption is variable, especially for the older drugs, and may be impaired by foods and multivalent cations (calcium, iron, aluminum). Tetracyclines have a wide tissue distribution and cross the placental barrier. All of the tetracyclines undergo entero-hepatic cycling. Doxycycline is excreted mainly in feces the other drugs are eliminated primarily in the urine. The half-lives of doxycycline and minocycline are longer than those of other tetracyclines. 

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