Oral minocycline is an antibiotic used to treat a variety of conditions, such as pneumonia and urinary tract infections. Some people also take it to treat acne.

Minocycline belongs to a class of antibiotics called tetracyclines, which prevent bacteria from making the proteins they need to grow.

Your doctor might prescribe minocycline if you have inflamed acne that hasn’t responded to other antibiotics, such as doxycycline. Like minocycline, doxycycline belongs to the tetracycline family, but it tends to be milder and cause fewer side effects.

Read on to learn more about taking minocycline for acne, including how long it takes to work and potential side effects.

Minocycline treats acne by both killing bacteria and reducing inflammation. Minocycline only treats active acne, not acne scars.

Propionibacterium acnes is bacteria found on most people’s skin. Sometimes it builds up in your pores, causing acne. Taking minocycline can help to kill P. acnes.

Minocycline also has anti-inflammatory properties, which can help to reduce redness and swelling caused by inflamed acne. You doctor might also prescribe an additional treatment, such as a topical acne cream, to use along with minocycline.

For acne, your doctor will likely prescribe a form of minocycline called Solodyn, which comes in the form of a slow-release capsule.

You can take minocycline at any time of day, with or without food. However, it’s best to drink a full glass of water with each dose to reduce irritation in your esophagus or stomach. Don’t take more than prescribed by your doctor. This can increase your risk of side effects.

Oral antibiotics can take about six to eight weeks to start working, so you won’t see results right away. Even if you aren’t seeing any improvement, it’s important to keep taking minocycline as directed by your doctor.

Sometimes, bacteria become resistant to antibiotics over time. This usually happens when you don’t take antibiotics long enough for them to kill off all the bacteria. The bacteria learn how to survive antibiotic treatment, making them especially hard to kill.

To avoid this, your doctor will likely prescribe minocycline for at least three months. If your acne improves before then, they might reduce your dose or switch you over to a topical antibiotic.

Minocycline may cause several mild to severe side effects. These include:

  • nausea and vomiting
  • diarrhea
  • changes in the color of your skin, nails, teeth, or gums
  • changes in the color of your urine
  • ringing in your ears
  • hair loss
  • dry mouth
  • tongue swelling
  • throat irritation
  • genital or rectal inflammation and itching
  • numbness or tingling of your skin

Over time, minocycline can build up in your body, leading to areas that look like dark bruises. While this discoloration usually goes away, it can take several years.

In rare cases, minocycline causes more serious symptoms. Stop taking minocycline and contact your doctor right away or seek emergency treatment if you notice any of the following symptoms:

  • blurry vision
  • severe headache
  • joint pain
  • rash
  • hives
  • facial swelling
  • yellow-tinted skin or eyes accompanied by dark urine
  • chest pain
  • severe nausea and vomiting
  • seizures
  • trouble breathing or swallowing
  • increased bleeding or bruising
  • bloody or watery diarrhea

Minocycline doesn’t work for everyone. If you already take certain medications, they can make minocycline less effective or increase your risk of serious side effects.

Before starting minocycline, tell your doctor if you already take:

  • birth control pills
  • retinoids, such as isotretinoin
  • penicillin
  • ergot medications for migraines
  • antacids containing aluminum, calcium, magnesium, or iron

You should also avoid taking minocycline if you’re pregnant or breastfeeding. In addition, children under the age of 8 shouldn’t take minocycline or other tetracycline antibiotics.

Minocycline is an antibiotic that can help to treat inflammatory acne in adults. In addition to killing acne-causing bacteria, it also reduces redness and inflammation. If you have inflammatory acne that hasn’t responded to other treatments, talk with your doctor about whether minocycline might be an option for you.