Tetracyclines food interactions

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... 

Rx of pneumonia, skin, soft tissue Infxns, osteomyelitis caused by penicillinase-producing staphylococci Action Bactericidal X cell wall synth Dose Adults. 250-500 mg qid Feds <40 kg, 12.5-100 mg/kg/d - qid take on empty stomach Caution [B, ] Contra Component orPCN sensitivity Disp Caps 125, 250, 500 mg soln 62.5 mg/5 mL SE N/D, abd pain Interactions T Effects W/ disulfiram, probenecid T effects OF MRX, X effects W/ macrolides, tetracyclines, food X effects OF OCPs, warfarin EMS Monitor for signs of electrolyte disturbances and hypovolemia d/t D OD May cause N/V/D, behavior changes, urinary retention, skin rash and Szs symptomatic and supportive... 

Adverse effects of tetracyclines include resistant bacteria, folliculitis, candidiasis, gastrointestinal upset, and phototoxic effects. Tetracyclines must not be combined with systemic retinoids because of the increased probability for development of intracranial hypertension. Tetracycline is used in the treatment of moderate to severe acne vulgaris. It is the least expensive of the tetracyclines and therefore often prescribed for initial therapy. A common initial approach includes tetracycline 1 g daily (500 mg twice daily), 1 hour before meals after 1 or 2 months, when marked improvement of inflammatory lesions is observed, the dose may be decreased to 500 mg every day, for another 1 or 2 months. Drawbacks to the use of tetracycline include also a drug-food interaction with dairy prodncts. 

There seem to be no direct clinical studies with calcium-containing antacids, but a clinically important interaction seems almost a certainty, based on in vitro studies with calcium carbonate, calcium in milk, (see Tetracyclines + Food or Drinks , p.347), dicalcium phosphate, and calcium as an excipient in tetracycline capsules. 

Patients should be warned about taking any antacids and indigestion preparations. Instead of using antacids to minimise the gastric irritant effects of the tetracyclines it is usually recommended that tetracyclines are taken after food, however it is not entirely clear how much this affects their absorption (see Tetracyclines + Food or Drinks , p.347). Hj-recep-tor antagonists may be suitable non-interacting alternatives to antacids in some situations, see Tetracyclines + Hj-receptor antagonists , p.348. 

There are problems as well in the absorption of certain drugs in the presence of specific food components. L-Dopa absorption may be inhibited in the presence of certain amino acids formed from the digestion of proteins [43], The absorption of tetracycline is reduced by calcium salts present in dairy foods and by several other cations, including magnesium and aluminum [115-117], which are often present in antacid preparations. In addition, iron and zinc have been shown to reduce tetracycline absorption [118], Figure 17 illustrates several of these interactions. These cations react with tetracycline to form a water-in-soluble and nonabsorbable complex. Obviously, these offending materials should not be co-administered with tetracycline antibiotics. 

Minocycline (Solodyn) [Antibiotic/Tetracycline] Uses Acne Action Tetracycline, bactmostatic Dose Adults Peds >12 y. 1 mg/kg PO daily X 12wk w/ food to -1- irritation Caution [C, ] assoc w/ pseudomembranous colitis w/ renal impair Contra AU gy, women of childbearing potential Disp Tabs SE D, HA, fevCT, rash, joint pain, fatigue, dizziness Interactions t Effects OF digoxin, oral anticoagulants t risk of n hrotox W/ methoxyflurane X effects W/... 

We have already met several of the important concepts in this topic, so now it is time to round them up and bring out the major principles. In the first place drug molecules clearly might interact with food molecules in the lumen of the gut. Perhaps the best-known example of this is the interaction between the tetracyclines and dietary calcium and iron. The binding, which occurs between them, produces a chelate, which is not particularly lipid-soluble, and therefore the overall absorption of tetracycline may be reduced to the point where plasma levels do not achieve effective antibiotic concentrations. The commonest dietary constituent to produce this binding is milk with its high calcium content. Tetracycline ingestion should be separated from food as far as possible. 

Doxycydine (Adoxa, Periostal-, Oracea, Vibramycin, Vibra-Tabs) [Anribiotic/Tetracycline] Uses Broad-spectrum antibiotic acne vulgaris, uncomplicated GC, Chlamydia sp, PID, Lyme Dz, skin Infxns, anthrax, malaria prophylaxis Action Tetracycline bacteriostatic X- protein synth Dose Adults. 100 mg PO ql2h on 1st d, then 100 mg PO daily bid or 100 mg IV ql2h acne daily dosing, Chlamydia 7d, Lyme Dz 14—21 d, PID 14 d Peds >8 y 5 mg/kg/24 h PO, to a max of 200 mg/d - daily-bid Caution [D, +] Hepatic impair Contra Children <8 y, severe hepatic dysfxn Disp Tabs, caps, syrup, susp, inj SE D, GI disturbance, photosens Interactions T Effects OF digoxin, warfarin 1 effects W/ antacids, Fe, barbiturates, carbamazepine, phenytoins, food 4-effects OF penicillins EMS Monitor for signs of electrolyte disturbances and hypovolemia d/t D monitor for S/Sxs of super Infxn T risk of photosensitivity Rxns antibiotic of choice for the Tx and prophylaxis of anthrax exposure expired tetracyclines have been known to cause nephrotox OD May cause adverse GI effects symptomatic and supportive... 

Which of the following foods can interact with a tetracycline to reduce its effectiveness ... 

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. 

Chemical interactions in the gastrointestinal tract between nutrients and drugs may considerably reduce the absorption of some drugs calcium ions from dairy products form insoluble and therefore nonabsorbable complexes with the antibiotic tetracycline. On the other hand, certain drugs are irritants to the gastrointestinal tract (nonsteroidal antiinflammatory drugs and potassium chloride tablets) and must be ingested with food. 

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