Oral antibiotics (tetracycline, minocycline, doxycycline) in acne treatment

Acne in its more severe form has the potential to scar and permanently disfigure young adults, the resulting psychological and social damage being more severe when the face is involved. Such inflammatory acne has, therefore, to be immediately and properly treated. Various systemic treatments may be the best options in such cases. Oral antibiotic treatment is one of the available options.

Oral antibiotics treatment is the first choice when:

  • Acne is of a moderate to severe type.
  • Acne is not cured by topical treatment.
  • Acne covers a large part of the body, particularly the chest back and shoulders.

Tetracycline, and its second generation derivatives minocycline and doxycycline, are among the most common oral antibiotics used in systemic treatment. These antibiotics suppress Propionibacterium acnes growth and also have anti-inflammatory properties. They can also reduce the number of comedones. The effectiveness of these drugs depends on their ability to penetrate the micro environment of the pilosebaceous follicles where the propionibacterium resides. The more penetration the better is the efficacy of the oral antibiotic. Clinical experience and data available to date show that minocycline and doxycycline are more effective than tetracycline.

Oral antibiotics are a long term therapy in acne, the normal duration of treatment being 4 to 6 months. Therefore, before prescribing these drugs, their reactions with drugs already being taken by the patients should be considered. For women with acne, a combined therapy of oral antibiotics and hormonal treatment, where oral contraceptives are used, is recommended. The common view that oral antibiotics reduce the efficacy of the oral contraceptives is largely unfounded, since the failure rates of the contraceptives with or without antibiotics is almost the same according to published research studies.


Tetracycline is a safe drug and generally healthy patients on this drug need not be regularly monitored. It is often effective in previously untreated cases of severe acne. Random trials have shown 50% to 60% rate of improvement in inflammatory acne. Treatment failures occur because of poor compliance, inadequate treatment duration, folliculitis development, bacterial resistance or high sebum secretion. It is one of the least expensive antibiotic drugs which makes it a popular choice. The main disadvantage of tetracycline is that it needs to be taken on an empty stomach since its absorption, and therefore its effectiveness, is reduced by any intake of food.

Side effects of tetracycline are gastrointestinal problems, vaginal candidiasis and photosensitivity. These drugs can also cause permanent bone and teeth pigmentation in some cases. They are not recommended for pregnant women and children below 12 years of age. A general complaint is frequent abdominal problems.


Minocycline is the most frequently prescribed oral antibiotic because the response to its use in treatment protocols is quicker. This is so because its penetration of the pilosebaceous hair follicles is better. But the view that it should be a first line of treatment has few supporters. Unlike tetracycline, minocycline can be taken with meals as food affects its absorption less. It is one of the most expensive drugs which can be an issue in countries with public state health care systems. Currently the view is that, though minocycline is most effective in moderate acne, its effectiveness compared to other treatments is yet to be determined.

Minocycline can cause headaches, vertigo, and hyperpigmentation of the skin. It can also cause some allergic reactions, and very rarely autoimmune disorders like autoimmune hepatitis, hypersensitivity reactions like hepatitis and pneumonitis and also death due to hepatoxicity and myocardial necrosis! Gastro intestinal problems are much less compared to those caused by tetracycline because minocycline is absorbed better when given orally. Patients on minocycline should be checked every 3 to 4 months for liver function and antinuclear factor in their blood.


Doxicycline can be taken with meals as this drug also penetrates the pilosebaceous follicles as well as minocycline. Among the three drugs, doxicycline is most likely to cause dose dependent photosensitivity reactions. Doxicycline, like minocycline, causes less gastrointestinal problems than tetracycline.

The use of doxicycline in lower doses in inflammatory acne has been found to be not only effective, but also safe since side effects are fewer and risk of developing bacterial resistance is lower compared to tetracycline and minocycline. If further studies confirm this benefit, it is likely that lower doses will become standard.

Bacterial resistance

A disturbing development in recent years in antibiotic treatment of acne has been a marked increase in bacterial resistance to these drugs. Several studies have confirmed this trend. Therefore, reducing bacterial resistance is now a primary aim in acne treatment. However, compared to other antibiotics, such as erythromycin, resistance is less common with tetracycline and doxicycline and rare with minocycline. Some strategies adopted for reducing resistance with oral antibiotics are; minimizing use of antibiotics, discontinuing oral antibiotics when acne control is achieved, and prescribing the same oral antibiotic for re-treatment.