Tetracyclines renal disease

Two tetracyclines have sufficiently distinctive features to warrant separate mention. Doxycycline, with its longer half-hfe and lack of nephrotoxicity, is a popular choice for patients with preexisting renal disease or those who are at risk for developing renal insufficiency. The lack of nephrotoxicity is related mainly to biliary excretion, which is the primary route of doxycycline elimination. Doxycycline is the preferred parenteral tetracycline Doxycycline is a potential first-hne agent in the prophylaxis of anthrax after exposure. Doxycycline is the treatment of choice for the primary stage of Lyme disease in adults and children older than 8 years. 

Tetracyclines induce photosensitisation and other rashes. Liver and pancreatic damage can occur, especially in pregnancy and with renal disease, when the drugs have been given i.v. Rarely tetracyclines cause benign intracranial hypertension, dizziness and other neurological reactions. 

Similar to furosemide. Narrower dose-response curve than furosemide. Increased azotemia in patients with renal disease taking tetracycline. Ethacrynate sodium is used intravenously to treat acute pulmonary edema. 

Because acid-pepsin disease rarely occurs in the absence of gastric acid and pepsin, antacids are highly effective in its overall management. Antacids consist of a mixture of magnesium, aluminum, and calcium compounds. Their efficacy is based on their inherent ability to react with and neutralize gastric acid. Sodium bicarbonate, which may leave the stomach rapidly, can cause alkalosis and sodium retention. Calcium salts may produce hypercalcemia, which can be detrimental in patients with impaired renal function. Aluminum salts may decrease the absorption of tetracyclines and anticholinergic drugs. 

Tetracyclines usually are the preferred agents for the treatment of rickettsial diseases. In patients allergic to these drugs, in those with reduced renal function, in pregnant women, and in children <8 years of age who require prolonged or repeated courses of therapy, chloramphenicol may be the drug of choice. Rickettsial diseases, such as Rocky Mountain spotted fever, respond well to chloramphenicol. For adults, a dose of 50 mg/kg/day is recommended for all the rickettsial diseases. The daily dose of chloramphenicol for children with these diseases is 75 mg/kg, divided into equal portions and given every 6-8 hours. Therapy should be continued until the patient has improved and is afebrile for 24—48 hours. 

Selective uses Specific tetracycUnes are used in the treatment of gastrointestinal ulcers caused by Helicobacter pylori (tetracycline), in Lyme disease (doxycycline), and in the meningococcal carrier state (minocycline). Doxycycline is also used for the prevention of malaria and in the treatment of amebiasis (Chapter 53). Demeclocycline inhibits the renal actions of ADH and is used in the management of patients with ADH-secreting tumors (Chapter 15). 

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