Comparison
Doxycycline and azithromycin, compared from both labels
Two antibiotics that appear side by side for the same infections, and the labels differ less on what they treat than on how they are taken. One is a course of days, the other can be a single dose, and that shapes almost everything else.
From the approved label
The two labels, side by side
| Doxycycline hyclate | Zithromax | |
|---|---|---|
| Approved uses | Doxycycline hyclateRickettsial infections | ZithromaxAcute bacterial exacerbations of chronic bronchitis in adults |
| Forms and strengths | Doxycycline hyclateEach 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. | ZithromaxZITHROMAX tablets 250 mg and 500 mg; ZITHROMAX for oral suspension 100 mg/5 mL and 200 mg/5 mL |
| How it is taken | Doxycycline hyclateDosage 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. | ZithromaxRecommended Dosage for Adult Patients |
| Must not be used when | Doxycycline hyclateDoxycycline hyclate delayed-release tablets are contraindicated in persons who have shown hypersensitivity to any of the tetracyclines. | ZithromaxPatients with known hypersensitivity to azithromycin, erythromycin, any macrolide or ketolide drug.; Patients with a history of cholestatic jaundice/hepatic dysfunction associated with prior use of azithromycin. Hypersensitivity ZITHROMAX is contraindicated in patients with known hypersensitivity to azithromycin, erythromycin, any macrolide or ketolide drug. |
| Common side effects | Doxycycline hyclateAdverse reactions observed in patients receiving tetracyclines include anorexia, nausea, vomiting, diarrhea, rash, photosensitivity, urticaria, and hemolytic anemia. To report SUSPECTED ADVERSE REACTIONS, contact Alembic Pharmaceuticals Limited at 1-866-210-9797 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. | ZithromaxMost common adverse reactions are diarrhea (5 to 14%), nausea (3 to 18%), abdominal pain (3 to 7%), or vomiting (2 to 7%).; most common adverse reactions in patients receiving a single-dose regimen of 1 gram of ZITHROMAX were related to the gastrointestinal system and were more frequently reported than in patients receiving the multiple-dose regimen. |
| Boxed warning | Doxycycline hyclate- | Zithromax- |
| Label holder | Doxycycline hyclateAlembic Pharmaceuticals Inc. | ZithromaxPfizer Laboratories Div Pfizer Inc |
| Label version | Doxycycline hyclate28 April 2026 | Zithromax24 July 2026 |
Built at page render time from the same imported label data as the medicine pages, so it cannot drift away from them.
Written by us
The difference that is real
Length of treatment. The azithromycin label describes short regimens, including single dose treatment for some genital infections, while doxycycline is taken twice a day across a course of days. For someone who will forget the second and fifth day, that difference is not a detail.
Range of approved uses. Both labels list infections well beyond sexual health, but they are not the same lists: doxycycline carries rickettsial infections and other uses that azithromycin does not, and azithromycin carries respiratory indications written for adults in its own terms. The overlap is real but partial.
Where the labels differ on who should not take them
Doxycycline belongs to the tetracyclines, and its label carries restrictions in pregnancy and in young children linked to effects on developing teeth and bone. Azithromycin is a macrolide and its label is built differently, with its own contraindication in people who had a reaction to it or to related medicines.
The interactions also differ in kind. Doxycycline is affected by what is taken alongside it, including products containing metal ions, and its label describes sensitivity to sunlight during treatment. Both points are practical rather than theoretical and are in the label sections on the two drug pages.
What the labels do not settle
Which of the two a person should be given. That is a clinical decision that depends on the infection, on the site of infection, on pregnancy and on what else the person takes, and national treatment guidance in each country weighs in on it in ways the labels do not.
Guidance in this area has also changed over time and differs between countries, which is another reason this page stops at what the two documents state rather than declaring a winner.
Questions
- Is a single dose as good as a week of tablets?
- The labels do not answer that comparison. Each states what its own regimen is approved for; putting them in order of preference is what national guidance and the prescriber do.
- Can either be taken in pregnancy?
- The doxycycline label carries restrictions tied to the tetracycline class in pregnancy. Azithromycin is written differently. Anyone pregnant or trying to conceive should raise it before treatment rather than compare labels alone.
- Why do both labels list infections that have nothing to do with sexual health?
- Because both are general antibiotics approved across many infections. This catalogue shows the sections relevant here, and the full approved list is in the label on each drug page.
See also
Sources
- Doxycycline Hyclate: prescribing informationDailyMed, US National Library of Medicine. Label version 28 April 2026
- Zithromax: prescribing informationDailyMed, US National Library of Medicine. Label version 24 July 2026