Tetracycline dosing

It is important to use the tetracyclines cautiously in patients witii renal function impairment, hi addition, doses greater that 2 g d can be extremely damaging to die liver. The nurse should carefully check die expiration dates of die tetracyclines before administration because degradation of the tetracyclines can occur after degradation, the agents are highly toxic to the kidneys. 

Antacids also have clinically significant drug interactions with tetracycline, ferrous sulfate, isoniazid, quinidine, sul-fonylureas, and quinolone antibiotics. Antacid-drug interactions are influenced by antacid composition, dose, dosage schedule, and formulation. 

BSS 525 mg four times a day + metronidazole 250 mg four times a day + tetracycline 500 mg four times a day + H2RA (conventional ulcer-healing dose)c... 

Although tetracycline, doxycycline, and minocycline are the most commonly prescribed oral antibiotics for acne, erythromycin and clindamycin are appropriate second-line agents for use when patients cannot tolerate or have developed resistance to tetracycline or its derivatives.3 See Table 62-3 for antibiotic dosing guidelines. 

Tetracycline Tablets, capsules 250, 500 mg 500 mg twice daily before meals Maintenance dose 500 mg daily Gl upset, phototoxicity, tooth discoloration, drug and food interactions... 

Alternatives Oral doxycycline 100 mg twice daily for 2 weeks or tetracycline 500 mg by mouth four times daily for 2 weeks. Limited literature also supports the use of ceftriaxone 1 g intramuscularly or intravenously once daily for 10 days or oral azithromycin as a single 2-g dose.13... 

Alternative treatments for non-pregnant penicillin-allergic patients doxycycline 100 mg orally twice daily for 2 weeks, or tetracycline 500 mg four times daily for 2 weeks limited data support ceftriaxone 1 g once daily IM or IV for 8 to 10 days or azithromycin, 2 g orally (single dose). 

Example. A 250 mg dose of tetracycline was administered to a patient by rapid IV injection. The initial plasma concentration (C ) was 2.50pg/mL. After 4hours the plasma concentration was 1.89pg/mL. What is the biological half-life of tetracycline in this patient ... 

The most important evidence is probably offered by a recent double-blind, randomized trial which showed a better therapeutic effect of rifaximin in comparison to tetracycline in a cohort of SIBO syndrome patients [42] in particular, rifaximin administration produced a significant reduction of breath hydrogen levels in fasting conditions, peak of hydrogen excretion and cumulative breath hydrogen excretion after an oral dose of 50 g of glucose (fig. 1). Normalization of the test results was evident in 70% of the sample studied. 

The answer is d. (Hardman, p 1575.) Isotretinoin is actually a form of high-dose vitamin A therapy Vitamin A itself or retinol (vitamin A could be used, but they have less advantageous pharmacokinetic properties. Antibiotics such as tetracyclines are used in acne, but they have little effect on the nodulocystic form... 

Erythromycin has efficacy similar to tetracycline, but it induces higher rates of bacterial resistance. Resistance may be reduced by combination therapy with benzoyl peroxide. Erythromycin can be used for patients who require systemic antibiotics but cannot tolerate tetracyclines, or those who acquire bacterial resistance to tetracyclines. The usual dose is 1 g/day with meals to minimize GI intolerance. 

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. 

Trimethoprim-sulfamethoxazole (or trimethoprim alone) is a second-line oral agent that may be used for patients who do not tolerate tetracyclines and erythromycin or in cases of resistance to these antibiotics. The adult dose is usually 800 mg sulfamethoxazole and 160 mg trimethoprim twice daily. 

Antibiotics shorten the duration of diarrhea, decrease the volume of fluid lost, and shorten the duration of the carrier state (see Table 39-3). A single dose of oral doxycycline is the preferred agent. In children younger than 7 years of age, trimethoprim-sulfamethoxazole, erythromycin, and furazolidone can be used. In areas of high tetracycline resistance, fluoroquinolones are effective. 

Vibrio cholerae 01 or Doxycydine 300 mg oral single dose tetracycline 500 mg orally four times daily x 3 days or trimethoprim-0139 sulfamethoxazole DS tablet twice daily x 3 days norfloxacin 400 mg orally twice daily x 3 days or... 

Note Doses may be increased for more severe disease and may require modification in patients with organ dysfunction. Tetracyclines are rarely used in pediatric patients, particularly in those younger than 8 years of age because of tetracycline-induced permanent tooth discoloration. 

Tetracycline, 40 mg/kg/day in three divided oral doses. Trimethoprim/sulfa (TMP), four mg per kg per day/sulfa, 20 mg per kg per day in divided oral doses. 

A physician prescribes tetracycline suspension for a patient to be taken in doses of two teaspoonfuls four times a day for four days, and then one teaspoonful four times a day for two days. How many milliliters of the suspension should be dispensed to provide the quantity for the prescribed dosage regimen ... 

Quinolene antibiotics ciprofloxacin, levofloxacin, ofloxacin Tetracycline antibiotics doxycycline Penicillin antibiotics amoxicillin, penicillin V, Penicillin G Vaccines are available six doses at 0, 2, and 4 weeks, then 6, 12, and 18 months, followed by annual boosters See Tierno 2002 or other medical references for details on administration of medications and/or vaccines... 

Increased bilirubin levels are caused due to the intake of large doses of such drugs as chloroquine, vitamin K, sulpha-drugs, tetracyclines, paracetamol, nicotinic acid and monoamine oxidase inhibitors (e.g., iproniazid RP 1.0 nialamide RP 1.8 isocarboxazid RP 3.1 phenelzine RP 18 pheniprazine RP31 and tranylcypromine RP 45), where RP designates the Relative Potency based on the tiyptamine potentiation test. The elevated levels are due to hepatic injury, and... 

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. 

Since patients can rarely be relied upon to take (or be given) medication after fasting, and since itis common experience that doses are omitted more or less frequently the properties of doxycycline make it appear a promising successor to the first generation tetracyclines. This is even more likely since the antibacterial spectrum and activity is at least equal to that of tetracycline, and in the case of certain tetracycline-resistant bacteria doxycycline has (of all derivatives tested) shown the highest activity [35, 41]. 

Renal function impairment If renal impairment exists, even usual doses may lead to excessive systemic accumulation of the tetracyclines (with the exception of doxycycline and minocycline) and possible liver toxicity. Use lower than usual doses and/or extend the dosing interval. 

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