Doxycycline

Doxycycline is a tetracycline antibiotic that has both antimicrobial and anti-inflammatory properties. In ophthalmology, it's commonly used at low doses for blepharitis, meibomian gland dysfunction (MGD), and ocular rosacea—leveraging its anti-inflammatory effects more than its antibiotic properties.

How It Works

As an Antibiotic

• Inhibits bacterial protein synthesis
• Effective against many bacteria

Anti-Inflammatory Properties

In eye conditions, doxycycline is valued for:

• Inhibiting matrix metalloproteinases (MMPs)
• Reducing inflammation in lid margins
• Improving meibomian gland secretions
• Changing the fatty acid composition of meibum (gland oil)

These effects occur even at doses below typical antibiotic levels.

Common Uses in Eye Care

• Blepharitis—especially posterior blepharitis
• Meibomian gland dysfunction (MGD)
• Ocular rosacea
• Dry eye disease related to MGD
• Recurrent chalazia (eyelid cysts)

Dosing

Standard Anti-Inflammatory Dosing

• 20-50 mg twice daily or 40-100 mg once daily
• Duration: Often 6-12 weeks initially
• May be used longer term at low doses

Full Antibiotic Dosing

• 100 mg twice daily
• Used when infection is the primary concern
• Shorter courses typically

Commonly Prescribed Forms

• Doxycycline 50 mg or 100 mg capsules/tablets
• Oracea (40 mg doxycycline modified-release)—designed for anti-inflammatory use

How to Take

• With food or milk to reduce stomach upset
• Full glass of water
• Stay upright for at least 30 minutes after taking (prevents esophageal irritation)
• Avoid lying down right after taking
• Take at same time daily for best results

What to Expect

Timeline

• Some improvement in weeks
• Full benefit may take 6-12 weeks
• Often used as initial treatment, then tapered or stopped

Effects

• Reduced lid margin inflammation
• Improved meibomian gland function
• Better tear film quality
• Reduced dry eye symptoms

Side Effects

Common

• Sun sensitivity (photosensitivity)—use sunscreen, avoid prolonged sun
• Nausea or stomach upset
• Diarrhea
• Yeast infections

Less Common

• Esophageal irritation (prevent by taking upright with water)
• Headache
• Dizziness

Rare But Serious

• Severe skin reactions
• Liver problems
• Increased intracranial pressure

Precautions

Drug Interactions

• Antacids, calcium, iron—take 2-3 hours apart
• Warfarin—may increase bleeding risk
• Oral contraceptives—may reduce effectiveness
• Isotretinoin—avoid combination

Doxycycline vs. Other Options

Condition	Doxycycline Role	Alternatives
Blepharitis/MGD	First-line oral option	Azithromycin, lid hygiene alone
Ocular rosacea	Often first-line	Azithromycin, topical metronidazole
Dry eye	Adjunct for MGD component	Other dry eye treatments

Long-Term Use

Safety

• Low-dose doxycycline is generally safe for extended periods
• Used for months in rosacea and MGD
• Periodic monitoring may be recommended

When to Stop

• After adequate improvement (often 2-3 months)
• May relapse—can restart if needed
• Some patients need intermittent or maintenance therapy

Frequently Asked Questions

Why am I taking an antibiotic for dry eye/blepharitis?

At low doses, doxycycline works primarily as an anti-inflammatory, not an antibiotic. It improves meibomian gland function and reduces lid inflammation, which helps with dry eye caused by these problems.

How long will I need to take doxycycline?

Typically 6-12 weeks for initial treatment. Some patients can then stop, while others may need longer treatment or periodic courses. Your doctor will guide duration based on your response.

Why do I need to avoid the sun?

Doxycycline increases photosensitivity—your skin burns more easily. Use sunscreen SPF 30+ and wear protective clothing. Avoid prolonged sun exposure while taking it.

Can I take doxycycline with my calcium supplement?

Take them at least 2-3 hours apart. Calcium (and antacids, iron) binds to doxycycline and reduces absorption.

What if I get an upset stomach?

Take with food or milk (unlike some antibiotics, doxycycline can be taken with dairy). If stomach upset persists, discuss with your doctor.

Is doxycycline safe long-term?

Low-dose doxycycline for anti-inflammatory purposes is generally safe for extended use. Studies in rosacea show good long-term safety. Your doctor will monitor you appropriately.