> ## Documentation Index
> Fetch the complete documentation index at: https://docs.hi-doctor.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# Doxycycline 100mg — chlamydia first option

> How doxycycline 100mg treats uncomplicated chlamydia, the typical seven-day regimen, common side effects and who needs an alternative.

Doxycycline is a tetracycline antibiotic and a preferred treatment for many uncomplicated chlamydia infections. A test result, the site of infection and pregnancy status can all change the plan a doctor sets.

## What is doxycycline 100mg?

Doxycycline is taken as a capsule or tablet, often twice daily for chlamydia. The indication, regimen and follow-up depend on your history and country guidance — a licensed doctor decides whether it is appropriate, and prescribing is never automatic.

<Info>
  Active ingredient: doxycycline. Dosage: 100 mg.
</Info>

## How it works

Doxycycline binds to bacterial ribosomes and blocks production of the proteins the bacteria need to grow.

<CardGroup cols={3}>
  <Card title="Evidence-based first option" icon="star">
    Commonly recommended for uncomplicated chlamydia when no contraindication applies.
  </Card>

  <Card title="Covers infection sites" icon="magnifying-glass">
    The clinician checks genital, rectal and throat exposure so testing and follow-up fit the case.
  </Card>

  <Card title="Partner advice included" icon="users">
    Paired with advice on abstinence, partner notification and repeat testing when needed.
  </Card>
</CardGroup>

## Dosing

A common uncomplicated-chlamydia regimen is 100 mg twice daily for seven days. The diagnosis and local guidance determine the final course.

<Steps>
  <Step title="Before treatment">
    Confirm testing and pregnancy status.
  </Step>

  <Step title="Days 1–7">
    Take the prescribed doses evenly, twice a day.
  </Step>

  <Step title="Afterwards">
    Follow partner and sexual-contact advice.
  </Step>
</Steps>

## What has been reported

| Effect                         | Notes                                                                                                               |
| ------------------------------ | ------------------------------------------------------------------------------------------------------------------- |
| Nausea, indigestion, diarrhoea | Can occur                                                                                                           |
| Painful swallowing             | Water and staying upright reduce oesophageal irritation; seek advice for severe chest pain or difficulty swallowing |
| Sensitivity to sunlight        | Limit strong sun and use protective clothing and sunscreen                                                          |
| Thrush                         | Can occur during or after antibiotics                                                                               |

## Who it is not suitable for

* Pregnancy, where an alternative is needed
* A tetracycline allergy, or a relevant interacting medicine

<Warning>
  For severe, sudden or unexpected symptoms, call your local emergency number or go to the nearest emergency department, then let your doctor know through your account chat.
</Warning>

## How to take it

Swallow with a full glass of water while sitting or standing, and do not lie down for at least 30 minutes. Separate antacids and supplements containing iron, calcium, magnesium, aluminium or zinc as your pharmacist advises. Take every dose and finish the course even if symptoms settle. If a dose is missed, take it when remembered unless the next is near — do not double up.

<Accordion title="Contact your doctor if">
  * Severe pelvic or testicular pain, fever, vomiting, pregnancy, eye symptoms after exposure, or feeling acutely unwell
  * A severe allergic or skin reaction, severe headache with visual change, painful swallowing, or severe or bloody diarrhoea
  * A dose was missed repeatedly, sex occurred before the advised interval, a partner was not treated, or symptoms persist
</Accordion>

Keep in the original package, away from moisture and direct heat, and out of children's reach. Follow the temperature limit on your pack and do not use it after the expiry date.

## How Hi-Doctor handles it

An EU-licensed doctor reads your questionnaire and answers within 24 hours. If the doctor decides it is not safe to prescribe, the consultation fee is refunded in full. Follow-up happens in the private chat inside your account, under GDPR — no WhatsApp, no SMS.

For the full walkthrough of a prescribed course, see the [doxycycline chlamydia guide](https://hi-doctor.ai/guides/doxycycline).

Related: [azithromycin](/library/medicines/azithromycin), the alternative when doxycycline is unsuitable. See also [how a Hi-Doctor consultation works](/essentials/how-it-works), [safety and eligibility checks](/essentials/safety), and [pricing](/essentials/pricing).

## Start a consultation

<Card title="Sexual health consultation" icon="stethoscope" href="https://hi-doctor.ai/consultation/sexual-health/1">
  Answer the sexual health questionnaire and a registered doctor reviews it.
  They decide whether treatment is appropriate, which one, and at what dose —
  and declining is a normal outcome. See [what it costs](/essentials/pricing)
  and [how the review works](/essentials/how-it-works).
</Card>

<Warning>
  This page is reference information, not medical advice and not a prescription.
  Whether a medicine is appropriate for you is decided by a registered doctor
  after reviewing your consultation.
</Warning>