Doxycycline — uses, dosing, side effects & the brands that sell it · pharmaranks
Doxycycline: uses, dosing, side effects & brands
Doxycycline is a tetracycline-class drug sold in the U.S. under 14 brand and generic names, for anthrax, campylobacter infections and cholera. Below: what the FDA label says, every product that contains it, what the pills look like, and its recall record.
By the pharmaranks editorial team·Reviewed against the FDA (openFDA label, NDC Directory & Enforcement) sources·How we research
14 products — Doryx, Doryx Mpc and Atridox, and others
Prescription?
Prescription only
Generic available?
Yes
Half-life
about 16 to 22 hours in healthy adults
Typical price
about $0 for a 30-count supply
How doxycycline is dosed
From the FDA label for Doryx (application NDA050582). Other doxycycline products — different forms, different strengths — are dosed differently. Follow the label for the one you were prescribed.
The usual dosage and frequency of administration of doxycycline differs from that of the other tetracyclines. Exceeding the recommended dosage may result in an increased incidence of side effects. Adults: The usual dose of oral doxycycline hyclate tablets is 200 mg on the first day of treatment (administered 100 mg every 12 hours) followed by a maintenance dose of 100 mg/day. In the management of more severe infections (particularly chronic infections of the urinary tract), 100 mg every 12 hours is recommended. Pediatric Patients: For all pediatric patients weighing less than 45 kg with severe or life-threatening infections (e.g., anthrax, Rocky Mountain spotted fever), the recommended dosage is 2.2 mg/kg of body weight administered every 12 hours. Children weighing 45 kg or more should receive the adult dose. (See WARNINGS and PRECAUTIONS .) For pediatric patients with less severe disease (greater than 8 years of age and weighing less than 45 kg), the recommended dosage schedule is 4.4 mg/kg of body weight divided into two doses on the first day of treatment, followed by a maintenance dose of 2.2 mg/kg of body weight (given as a single daily dose or divided into twice daily doses). For pediatric patients weighing over 45 kg, the usual adult dose should be used. The therapeutic antibacterial serum activity will usually persist for 24 hours following recommended dosage. When…
Doxycycline side effects
Due to oral doxycycline’s virtually complete absorption, side effects of the lower bowel, particularly diarrhea, have been infrequent. The following adverse reactions have been observed in patients receiving tetracyclines: Gastrointestinal: anorexia, nausea, vomiting, diarrhea, glossitis, dysphagia, enterocolitis, inflammatory lesions (with monilial overgrowth) in the anogenital region, and pancreatitis. Hepatotoxicity has been reported rarely. These reactions have been caused by both the oral and parenteral administration of tetracyclines. Superficial discoloration of the adult permanent dentition, reversible upon drug discontinuation and professional dental cleaning has been reported. Permanent tooth discoloration and enamel hypoplasia may occur with drugs of the tetracycline class when used during tooth development. (See WARNINGS .) Rare instances of esophagitis and esophageal ulcerations have been reported in patients receiving capsule and tablet forms of the drugs in the tetracycline class. Most of these patients took medications immediately before going to bed. (See DOSAGE AND ADMINISTRATION .) Skin: toxic epidermal necrolysis, Stevens-Johnson syndrome, erythema multiforme, fixed drug eruption, skin hyperpigmentation, maculopapular and erythematous rashes. Exfoliative dermatitis has been reported but is uncommon. Photosensitivity is discussed above. (See WARNINGS .)…
Doxycycline and food
Dairy, calcium, iron & antacids
Separate the antibiotic from dairy, supplements, and antacids by a couple of hours — take it at the interval the label or your pharmacist specifies.
The elimination half-life of doxycycline is about 16 to 22 hours in healthy adults. This is the elimination half-life of doxycycline itself; it has no active metabolite with a longer half-life, and the half-life stays about the same (18 to 22 hours) even with severe kidney impairment and is not shortened by hemodialysis.
Half-life is how long the body takes to clear half a dose. It is not the same as how long a drug test can detect it, and it varies with age, kidney and liver function.
Frequently asked questions
What is doxycycline?
Doxycycline is an antibacterial drug synthetically derived from oxytetracycline, and is available as doxycycline hyclate tablets for oral administration. The chemical designation of doxycycline is 4-(Dimethylamino)-1,4,4a,5,5a,6,11,12a-octahydro-3,5,10,12,12a-pentahydroxy-6-methyl-1,11-dioxo-2-naphthacene-carboxamide monohydrochloride, compound with ethyl alcohol (2:1), monohydrate. The structural formula of doxycycline hyclate is: with a molecular formula of (C 22 H 24 N 2 O 8 •HCl) 2 •C 2 H 6 O•H 2 O and the molecular weight is 1025.89. Doxycycline is a light-yellow crystalline powder. Doxycycline hyclate is soluble in water. Doxycycline has a high degree of lipoid solubility and a low affinity for calcium binding. It is highly stable in normal human serum. Doxycycline will not degrade into an epianhydro form. Active Ingredient: Doxycycline hyclate USP equivalent to 100 mg of doxycycline. Inactive Ingredient: Microcrystalline cellulose and magnesium stearate. Tablet coating contains hypromellose, titanium dioxide, polyethylene glycol, FD&C yellow #6, polysorbate 80 and FD&C blue #2. Meet USP Dissolution Test 4. structural-formula
What kind of drug is doxycycline?
The FDA classifies doxycycline as a tetracycline-class drug. Tetracyclines slip inside bacteria and bind to the 30S part of their ribosome, the cell's protein-building machine. This blocks the bacteria from adding new amino acids, so they can't make the proteins they need to grow or multiply, letting the immune system clear the infection. If you are checking whether it is safe to combine with something else, the class is what matters — two drugs from the same class usually should not be stacked.
How long does doxycycline stay in your system?
The elimination half-life of doxycycline is about 16 to 22 hours in healthy adults — that is how long the body takes to clear half of a dose. This is the elimination half-life of doxycycline itself; it has no active metabolite with a longer half-life, and the half-life stays about the same (18 to 22 hours) even with severe kidney impairment and is not shortened by hemodialysis. Half-life is not the same as how long a drug test can detect the drug, and it varies with age, kidney and liver function.
Can you take doxycycline with other medicines?
Sources: FDA openFDA drug label, National Drug Code Directory, and Enforcement (recall) database. This page reproduces public FDA data and is not medical advice. Dosing is set by your prescriber.
Who shouldn’t take doxycycline
This drug is contraindicated in persons who have shown hypersensitivity to any of the tetracyclines.
Doxycycline drug interactions
Because tetracyclines have been shown to depress plasma prothrombin activity, patients who are on anticoagulant therapy may require downward adjustment of their anticoagulant dosage. Since bacteriostatic drugs may interfere with the bactericidal action of penicillin, it is advisable to avoid giving tetracyclines in conjunction with penicillin. Absorption of tetracyclines is impaired by antacids containing aluminum, calcium, or magnesium, and iron-containing preparations. Absorption of tetracyclines is impaired by bismuth subsalicylate. Barbiturates, carbamazepine, and phenytoin decrease the half-life of doxycycline. The concurrent use of tetracycline and Penthrane ® (methoxyflurane) has been reported to result in fatal renal toxicity. Concurrent use of tetracycline may render oral contraceptives less effective.
It depends on the medicine. We check it against the FDA labels rather than guessing: our interaction checker searches each drug's own label for the other and quotes what it says, naming the section it came from. Run doxycycline against whatever else you take — and remember that a label not naming a drug is not the same as that combination being safe.
What brand names is doxycycline sold under?
We track 14 doxycycline-containing products in the U.S.: Doryx, Doryx Mpc, Atridox, Doxycycline Hyclate, Doxycycline, Vibramycin, Doxy-Lemmon and Doxychel Hyclate, and 6 more. They are the same active ingredient; they differ in form, manufacturer, price and FDA recall record.
What forms does doxycycline come in?
Across the brands we track, doxycycline is currently marketed as tablet, delayed release, capsule, delayed release, system, extended release, capsule, powder, tablet, injectable and suspension, per the FDA's National Drug Code Directory. Each form is dosed differently — follow the label for the exact product you were prescribed.
Is there a generic doxycycline?
Yes. Our catalog lists 4 generic doxycycline products alongside the brand versions. A generic has the same active ingredient and must meet the FDA's bioequivalence standard; it usually costs less. Ask your pharmacist which one your plan covers.
Has doxycycline been recalled?
The FDA's Enforcement database lists 1 recall record whose product description mentions doxycycline. The most recent: Doxycycline Hyclate Tablets (Sep 29, 2025). A recall applies to specific lots, not to the drug as a whole — check the record for the affected lot numbers.