Patients with moderate acne have more lesions, characterised by papules and pustules, and usually require oral treatment, including an oral rather than topical antibiotic. Women with unresponsive acne may benefit from the oral contraceptive pill, cyproterone acetate or spironolactone.
Oral antibiotics have been prescribed for decades as an acne treatment. They work by suppressing C. acnes growth and have anti-inflammatory action. Due to the growing concern over antibiotic resistance, use with topical benzoyl peroxide, topical retinoid and/or a probiotic is recommended. Oral antibiotics should not be used simultaneously with a topical antibiotic and the duration of usage should be limited to three to six months.
Doxycycline is probably the most prescribed oral antibiotic, at an average daily dosage of 100 mg daily; however, doses can range from 50 to 200 mg daily. Doxycycline should be taken with water, not milk, and should not be taken before lying down or at bedtime because of the risk of oesophageal irritation. It is not recommended for children under 12 years of age due to the risk of tooth discolouration, or in women who are pregnant or breastfeeding.
Minocycline at a dosage of 100 mg daily is also prescribed. However, there are rare safety issues associated with its use including minocycline-induced hepatitis, drug-induced lupus-like hypersensitivity syndrome and hyperpigmentation.
Erythromycin 500 mg twice daily is also effective but C. acnes resistance and gastrointestinal side effects are more common. It is used in children and pregnant women, in whom tetracycline is contraindicated.
Other antibiotics such as trimethoprim can also be used as third-line therapy at a dosage of 200 to 300 mg twice daily. Although not commonly used, azithromycin has been considered as effective as doxycycline in some trials.19 The dosage of 500 mg once daily for three days per week or in cycles of 10 days for 12 weeks are the most commonly used regimens.20
The most commonly prescribed antiandrogen hormonal therapies for moderate acne are the oral contraceptive pill, cyproterone acetate and spironolactone. These can be prescribed as monotherapy, or as oral contraceptive/spironolactone or oral contraceptive/cyproterone acetate combinations. These therapies can be effective in women with acne, especially those who show resistance to other therapies, and can even be effective when serum androgen levels are normal. They work by decreasing ovarian and adrenal androgen production and also inhibit the local activity of androgen nuclear receptors on sebocytes and keratinocytes.21 Before prescribing an oral contraceptive, it is important to check for any contraindications.
Women over the age of 25 years may have higher rates of treatment failure.17 Suspect hormonal acne in women who fail multiple courses of systemic antibiotic medications or if there is a recurrence of acne shortly after treatment with isotretinoin.22,23
Patients may not see an improvement in their symptoms until after three months of taking an oral contraceptive for acne and the best response rate may not be seen until after six to nine months of treatment. Acne has been shown to improve in 50 to 90% of cases.16 Many patients may experience a flare of their hormonal acne when their long-term oral contraceptives are ceased. Some patients may also have a worsening of their acne when contraceptive implants are used.24