Doxycycline
The first-line antibiotic for chlamydia in current European and British guidance, and an old, cheap, well-documented medicine.
Prescription onlyHow to get it legally
- Class
- Tetracycline antibiotic
- Sold as
- Vibramycin, Doxyhexal
- approved labels read
- 1
On this page
From the approved label
FDA · EN
Doxycycline hyclate
- Approved uses
- Uncomplicated urethral, endocervical or rectal infections caused by Chlamydia trachomatis.
- Nongonococcal urethritis caused by Ureaplasma urealyticum.
- Lymphogranuloma venereum caused by Chlamydia trachomatis.
- Granuloma inguinale caused by Klebsiella granulomatis.
- Uncomplicated gonorrhea caused by Neisseria gonorrhoeae.
- Respiratory tract infections caused by Mycoplasma pneumoniae.
- Forms and strengths
- Each tablet contains specially coated pellets of doxycycline hyclate USP equivalent to 75 mg of doxycycline.
- Doxycycline hyclate delayed-release tablets USP, 100 mg having functional scoring are white, oval tablets containing yellow specks, debossed with "L242" on one side and score line on the other side.
- How it is taken
- Dosage in Adult Patients: The usual dosage is 200 mg on the first day of treatment (administered 100 mg every 12 hours) followed by a maintenance dose of 100 mg daily.; In the management of more severe infections (particularly chronic infections of the urinary tract), 100 mg every 12 hours is recommended.
- Dosage in 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 dose is 2.2 mg per kg of body weight administered every 12 hours. Pediatric patients weighing 45 kg or more should receive the adult dose.;
- Must not be used when
- Doxycycline hyclate delayed-release tablets are contraindicated in persons who have shown hypersensitivity to any of the tetracyclines.
- Interactions
- Patients who are on anticoagulant therapy may require downward adjustment of their anticoagulant dosage
- Avoid co-administration of tetracyclines with penicillin
- Absorption of tetracyclines, including doxycycline hyclate delayed-release tablets, is impaired by antacids containing aluminum, calcium, or magnesium, bismuth subsalicylate and iron-containing preparations
- Concurrent use of tetracyclines, including doxycycline hyclate delayed-release tablets, may render oral contraceptives less effective
- Barbiturates, carbamazepine and phenytoin decrease the half-life of doxycycline
- Warnings and precautions
- The use of drugs of the tetracycline-class during tooth development (last half of pregnancy, infancy and childhood to the age of 8 years) may cause permanent discoloration of the teeth (yellow-gray-brown).
- Clostridiodes difficile -associated diarrhea (CDAD) has been reported: Evaluate patients if diarrhea occurs.
- Photosensitivity manifested by an exaggerated sunburn reaction has been observed in some individuals taking tetracyclines. Limit sun exposure.
- Overgrowth of non-susceptible organisms, including fungi, may occur. If such infections occur, discontinue use and institute appropriate therapy.
- Common side effects
- Most commonly reported adverse reactions in both treatment groups were nausea, vomiting, diarrhea, and bacterial vaginitis, Table 1.
- Pregnancy
There are no adequate and well-controlled studies on the use of doxycycline in pregnant women. The vast majority of reported experience with doxycycline during human pregnancy is short-term, first trimester exposure. There are no human data available to assess the effects of long-term therapy of doxycycline in pregnant women such as that proposed for the treatment of anthrax exposure.
- How it acts
Doxycycline is a tetracycline-class antimicrobial drug.
This section reports the approved product information. The wording is condensed from the regulator's own summary, and the full document is linked under Sources.
Written by us
How it works
Doxycycline stops bacteria building the proteins they need to multiply. It covers a wide range of organisms, which is both its strength and the reason it should not be taken speculatively: taking an antibiotic that does not match the infection leaves the infection in place and contributes to resistance.
Original and generic
Generic everywhere and among the cheapest antibiotics available. The label on this page is from a generic manufacturer.
What it costs
A full course costs very little in any European pharmacy, and in most public health systems treatment for a diagnosed sexually transmitted infection is free or nearly free through sexual health services.
How to get it legally
Prescription only. This is the entry in this category where testing before treatment matters most, because prescribing depends on which organism is present. Public sexual health services test and treat at no cost in the United Kingdom, and publicly funded testing exists in Germany, Italy and France. An online clinic is a reasonable route for a confirmed diagnosis, and a poor substitute for a test.
Comparison
See also
Questions
- Can it be taken without a test?
- It can be prescribed, but the more useful question is whether it should be. Different infections need different antibiotics, and treating the wrong one hides the symptoms without clearing the cause.
- Why the warnings about sunlight and about lying down?
- Both are in the label's warnings section, one about skin sensitivity and one about irritation of the oesophagus. Both are practical instructions rather than rare risks.
- Does it interact with the contraceptive pill?
- The interactions section of the label addresses this, and the current position there is more specific than the general advice that circulated for years. It is worth reading in the label section above.
Sources
- Doxycycline Hyclate: prescribing informationDailyMed, US National Library of Medicine. Label version 28 April 2026
- Drugs@FDA: ANDA213075US Food and Drug Administration
In this category
- ValaciclovirThe standard treatment for genital herpes, taken either as a short course during an outbreak or daily to reduce how often outbreaks occur.
- AciclovirThe original antiviral for herpes, still widely prescribed, taken more often per day than valaciclovir and costing even less.
- AzithromycinThe single-dose antibiotic that was once standard for chlamydia and has since moved down the guidance in most of Europe.
- Emtricitabine and tenofovir disoproxilPre-exposure prophylaxis: a daily tablet taken by people who do not have HIV, to prevent acquiring it. Prevention rather than treatment, with testing built into the label.
- ImiquimodA cream applied at home for external genital and perianal warts, which acts on the immune response rather than on the virus itself.
- PodophyllotoxinA gel applied at home for anogenital warts on a fixed rhythm of three days on and four days off, up to four cycles.
- FluconazoleAn antifungal taken by mouth, most often as a single dose for vaginal thrush, and in longer courses for candidiasis elsewhere in the body.
- MetronidazoleAn antimicrobial taken by mouth for trichomoniasis and for anaerobic infections, and the treatment that the label says should also be given to the sexual partner.