What is Doxycycline?
Doxycycline is a broad-spectrum tetracycline antibiotic used to treat a wide range of bacterial infections. In the context of sexual health, it is the preferred first-line antibiotic for the treatment of Chlamydia trachomatis infection (chlamydia) and non-gonococcal urethritis (NGU) in non-pregnant adults, as recommended by WHO and European STI treatment guidelines.
Doxycycline is listed on the WHO Model List of Essential Medicines and is one of the most widely used antibiotics in sexual health medicine globally. It is available in two salt forms — doxycycline hyclate and doxycycline monohydrate — which are clinically equivalent.
How does Doxycycline work?
Doxycycline inhibits bacterial protein synthesis by binding reversibly to the 30S ribosomal subunit of bacteria. This blocks the attachment of aminoacyl-tRNA to the messenger RNA-ribosome complex, preventing the addition of new amino acids to growing polypeptide chains.
The result is:
- Inhibition of protein synthesis: Bacteria cannot produce the proteins essential for growth, metabolism, and replication
- Bacteriostatic activity: Doxycycline stops bacterial growth and reproduction rather than directly killing bacteria, allowing the immune system to clear the infection
- Broad spectrum: Active against a wide range of gram-positive, gram-negative, and atypical organisms including intracellular pathogens such as Chlamydia, Mycoplasma, and Rickettsia species
Doxycycline’s ability to treat intracellular organisms (bacteria that live inside host cells) is particularly important in sexual health, where Chlamydia trachomatis is an obligate intracellular pathogen.
Pharmacokinetic properties:
- High oral bioavailability (~93%), nearly equivalent to intravenous dosing
- Long half-life (~18–22 hours), allowing twice-daily dosing
- Widely distributed in tissues, including into the genital tract
- Eliminated via bile and faeces (unlike most antibiotics excreted by the kidneys — less dose adjustment needed in renal impairment)
Who is Doxycycline for?
In sexual health, doxycycline is the preferred treatment for:
- Chlamydia (Chlamydia trachomatis): First-line treatment for uncomplicated genital chlamydia in non-pregnant adults (100 mg twice daily for 7 days)
- Non-gonococcal urethritis (NGU): First-line treatment, usually caused by Chlamydia trachomatis or Mycoplasma genitalium
- Lymphogranuloma venereum (LGV): Caused by Chlamydia trachomatis serovars L1–L3; treated with doxycycline 100 mg twice daily for 21 days
- Pelvic inflammatory disease (PID): Used as part of combination regimens
- Syphilis: Second-line option for patients allergic to penicillin (2–4 weeks depending on stage)
- Epididymo-orchitis: When caused by Chlamydia trachomatis
Doxycycline is not appropriate for:
- Pregnant women (contraindicated — use amoxicillin or erythromycin instead)
- Children under 12 years (risk of dental discolouration)
- Patients with known tetracycline allergy
- Viral or fungal infections
Posología
| Indicación | Dosis | Duración |
|---|---|---|
| Chlamydia (uncomplicated) | 100 mg twice daily | 7 days |
| NGU | 100 mg twice daily | 7 days |
| LGV | 100 mg twice daily | 21 days |
| Pelvic inflammatory disease (PID) | 100 mg twice daily | 14 days (part of combination) |
| Syphilis (early, penicillin allergy) | 100 mg twice daily | 14 days |
| Syphilis (late latent, penicillin allergy) | 100 mg twice daily | 28 days |
Doxycycline capsules/tablets should be swallowed with a full glass of water and taken in an upright position (not immediately before lying down) to prevent oesophageal irritation.
Efectos secundarios
Efectos secundarios frecuentes (afectan a entre 1 y 10 de cada 100 personas)
- Nausea
- Vomiting
- Diarrhoea
- Abdominal pain
- Photosensitivity (increased sensitivity to sunlight — use sunscreen and avoid prolonged sun exposure during treatment)
Efectos secundarios poco frecuentes
- Oesophageal irritation or ulceration (take with adequate water and do not lie down immediately after)
- Headache
- Dizziness
- Vaginal thrush (candidiasis) — antibiotic disruption of normal flora
- Skin rash
Efectos secundarios graves (raros)
- Severe photosensitivity reactions: Avoid direct sunlight and UV exposure during treatment
- Intracranial hypertension (pseudotumour cerebri): Rare — persistent headache, visual changes, or vomiting should be assessed by a doctor
- Serious allergic reactions: Including anaphylaxis, angioedema
- Clostridioides difficile colitis: Severe persistent diarrhoea
Doxycycline vs alternative antibiotics for chlamydia
| Antibiotic | Dose | Duration | Notes |
|---|---|---|---|
| Doxycycline (1st line) | 100 mg twice daily | 7 days | Preferred; highest efficacy for genital chlamydia |
| Zithromax/Azithromycin (1st line) | 1 g single dose | 1 day | Convenient; slightly lower rectal chlamydia efficacy |
| Amoxicillin | 500 mg three times daily | 7 days | Pregnancy alternative |
| Erythromycin | 500 mg four times daily | 7 days | Pregnancy alternative; GI side effects |
Doxycycline vs Azithromycin: Both are first-line options for uncomplicated genital chlamydia. A 2021 meta-analysis and updated European guidelines favour doxycycline as the preferred option for genital chlamydia due to higher microbiological cure rates, particularly for rectal infection. Azithromycin single-dose remains an alternative when adherence to a 7-day course is a concern.
How to access Doxycycline online in Europe
Doxycycline es un medicamento sujeto a prescripción médica en todos los estados miembros de la UE. No puede dispensarse legalmente sin una receta válida de un profesional médico autorizado.
Prescrivia opera como intermediario tecnológico: no prescribimos medicamentos, no empleamos médicos ni vendemos medicamentos. Nuestra plataforma conecta a los pacientes con médicos independientes registrados en la UE que pueden realizar evaluaciones de salud en línea confidenciales.
El proceso:
- Complete una evaluación de salud: Provide details of your symptoms, recent STI testing, sexual history, and any relevant allergies or current medications.
- Revisión médica: Un médico independiente registrado en la UE revisa su evaluación. If doxycycline is clinically appropriate, they may issue a prescription.
- Dispensación en farmacia: La receta se envía a una farmacia asociada autorizada de la UE para su dispensación y entrega directa.
Importante: Prescrivia does not guarantee that a prescription will be issued. A positive chlamydia test or strong clinical indication is typically required. All prescribing decisions are made independently by qualified medical professionals.
Información importante de seguridad
No tome Doxycycline si usted:
- Are pregnant or breastfeeding
- Are under 12 years of age
- Have a known allergy to tetracycline antibiotics
- Are taking isotretinoin (increased risk of intracranial hypertension)
Informe a su médico antes de taking Doxycycline si usted:
- Have liver disease
- Have systemic lupus erythematosus (SLE) — photosensitivity risk is increased
- Are taking antacids, calcium supplements, iron, or bismuth-containing products (take at least 2–3 hours apart)
- Are taking warfarin (monitoring of anticoagulation may be needed)
- Are taking oral contraceptives (additional contraceptive precautions are not required, but discuss with your doctor)
Notificación a la pareja: If diagnosed with chlamydia or another STI, sexual partners from the preceding 6 months should be informed, offered testing, and treated. This is essential to prevent reinfection.
Prueba de curación: A test of cure is not routinely recommended after standard doxycycline treatment for chlamydia, but may be advised in pregnancy, or if adherence was uncertain.
Fuentes
La información médica de esta página se basa en las siguientes fuentes:
- World Health Organization (WHO). WHO Guidelines for the Treatment of Chlamydia trachomatis. 2016. who.int
- European STI Guidelines Editorial Board. 2015 European guideline on the management of Chlamydia trachomatis infections. Journal of the European Academy of Dermatology and Venereology.
- World Health Organization (WHO). WHO Model List of Essential Medicines. 22nd edition, 2021.
- Dombrowski JC, et al. Doxycycline versus azithromycin for the treatment of rectal chlamydia in men who have sex with men. Clinical Infectious Diseases. 2021.
Este contenido se revisa periódicamente para reflejar las directrices clínicas actualizadas. Se proporciona únicamente con fines informativos y no constituye asesoramiento médico. Consulte siempre a un profesional sanitario cualificado para obtener asesoramiento relevante para sus circunstancias de salud individuales.
Frequently asked questions
- What is Doxycycline used for in sexual health?
- Doxycycline is a first-line antibiotic for the treatment of chlamydia (Chlamydia trachomatis), non-gonococcal urethritis (NGU), lymphogranuloma venereum (LGV), and certain cases of pelvic inflammatory disease (PID). It is also used as part of combination regimens for syphilis in penicillin-allergic patients.
- How long is the doxycycline course for chlamydia?
- The WHO and European STI guidelines recommend doxycycline 100 mg twice daily for 7 days as the preferred first-line treatment for uncomplicated genital chlamydia. For lymphogranuloma venereum (LGV), the same dose is continued for 21 days.
- Can I take Doxycycline with food?
- Doxycycline can and should be taken with food or milk to reduce the risk of oesophageal irritation and gastrointestinal side effects. However, avoid taking it with dairy products, calcium-rich foods, antacids, or iron supplements within 2–3 hours, as these can significantly reduce absorption.
- Is Doxycycline safe during pregnancy?
- No. Doxycycline is contraindicated during pregnancy and breastfeeding. It can affect fetal bone and tooth development and cause permanent tooth discolouration in the developing child. Pregnant women with chlamydia should be treated with amoxicillin or erythromycin instead — a doctor will advise on the appropriate alternative.
- Can I drink alcohol while taking Doxycycline?
- Moderate alcohol consumption does not significantly affect the efficacy of doxycycline, and the interaction is not considered clinically significant in most patients. However, alcohol may worsen gastrointestinal side effects, and heavy alcohol use can theoretically reduce doxycycline blood levels. It is generally advisable to avoid excessive alcohol during any antibiotic course.
Tratamientos
Prescrivia es únicamente una plataforma intermediaria. No prestamos servicios médicos, no prescribimos tratamientos ni dispensamos medicamentos. Todas las decisiones médicas son tomadas por médicos independientes registrados en la UE. Todos los medicamentos son dispensados por farmacias autorizadas de la UE. Esta plataforma facilita la conexión entre pacientes y profesionales sanitarios.