'European recommendations on the use of oral antibiotics for acne'

Non-rational prescribing of oral antibiotics in acne is common, and there is currently an unmet need for up-to-date guidelines that specifically address these issues. Presented here is a set of recommendations on the use of oral antibiotics in acne, developed by a group of European acne specialists, designed to be considered by dermatologists and general practitioners in their daily practice throughout Europe. Recommendations cover optimal choice of antibiotic, drug doses, duration of treatment, combination treatment, and maintenance therapy.

There are many different drugs available for the treatment of acne vulgaris, including oral and topical antibiotics, topical benzoyl peroxide, topical
retinoids, oral isotretinoin, oral anti-androgens, and zinc salts. Many guidelines on how these different agents can be optimally used have been published over the years. These include the 'Ad hoc committee report' on the use of systemic antibiotics for treatment of acne vulgaris (1975) [1]; the American Academy of Dermatology 'Guidelines for care of acne vulgaris' (1990) [2]; 'Treatment of acne vulgaris: guidelines for primary care physicians' (1991) [3]; 'Oral treatment of acne' in France (1999) [4]; and most recently the 'Global alliance to improve outcomes in acne' consensus recommendations (2003) [5].

Figure 1 shows the acne treatment algorithm proposed by the 'Global alliance', in which oral antibiotics, used in combination with topical retinoids, are recommended for the treatment of moderate to severe inflammatory acne.

Other than the 1975 ad hoc committee report [1], the other guidelines listed above provide general recommendations on acne management, but fall short of providing detailed guidance on the use of oral antibiotics. This is probably due to the fact that much of the clinical evidence derives from trials that vary greatly in acne definition, end-points, doses used, duration of treatments etc., making direct comparisons difficult. Perhaps as a consequence of this lack of guidance, there is considerable variation in the way in which antibiotics are used to treat acne across Europe, and their inappropriate use is alarmingly common (patients are often treated for excessively long periods of time, and/or there is much variation in antibiotic dosage given). The preferred choice of antibiotic varies from country to country, with first generation cyclines (tetracycline HCl, and oxytetracycline) very popular in the UK, minocycline preferred in Belgium, and lymecycline particularly popular among dermatologists in France, Italy, and Nordic countries. Some of these differences may be accounted for by climate (for example, doxycycline, known to have the potential to cause dose-dependent photosensitivity, is less commonly prescribed in Southern Europe during the summer), and by various pharmacoeconomic considerations.

Thus, despite the problems in forming truly evidence-based guidelines on the use of oral antibiotics in acne, there is clearly an unmet need for recommendations on the use of oral antibiotics that can be used in the daily practice of physicians treating acne across Europe. This paper therefore presents the available clinical data and expert opinion, followed by a set of detailed and user-friendly recommendations on many aspects of the use of oral antibiotics in acne.

Methodology

These recommendations were developed over a series of three meetings in 2002 and 2003. During the first two meetings, a core of six independent European acne specialists reviewed current practices around Europe; conducted a systematic literature review (using Medline) covering the years 1992 to 2003; and discussed personal experiences. In a final workshop, the findings of this core group were presented to the wider group of 23 acne specialists, mainly from Europe, but also Brazil and Morocco (Appendix 1) for discussion and review. Recommendations are based on efficacy, practical applicability in daily practice, safety/tolerability, antimicrobial resistance, and pharmacoeconomic considerations.

I. LITERATURE REVIEW

The pathophysiology of acne and rationale for using antibiotics

There are a number of pathophysiologic components to acne, including sebaceous gland hyperplasia with seborrhoea; altered follicular growth and differentiation; microbial colonization; and inflammation and other immune responses [5]. The precursor lesion in all acne is the microcomedone, which features altered follicular growth and differentiation, and sebaceous gland hyperplasia with seborrhoea. Microcomedones can then enlarge to form non-inflammatory closed or open comedones, and microbial colonization can result in the formation of inflammatory lesions (papules, pustules, or nodules). By using different agents in combination, acne pathophysiology can be targeted from a number of different angles simultaneously, improving therapeutic outcome [5].

For example, topical retinoids (some of which have proven anti-inflammatory properties) target the microcomedone, and are therefore suitable for use in combination with other drugs that target Propionibacterium acnes and inflammation, and may be suitable for maintaining remission following successful treatment [6].

Microorganisms that are commonly present on the skin of patients with inflammatory acne include the yeasts Pityrosporum spp., coagulase-negative staphylococci, and P. acnes [7]. Eradication of Pityrosporum spp., using antimycotic therapy, does not have any effect on acne [8], and use of antibiotics induces resistance in coagulase-negative staphylococci well in advance of observed responses to treatment [9]. Studies have shown that infection with the gram-positive, pleomorphic, anaerobic rod, P. acnes causes inflammation of sterile cysts [10], but that dead P. acnes or living Staphylococcus epidermidis do not cause inflammation [11]. Therefore P. acnes, has been implicated in inflammatory acne lesions.

The concentration of P. acnes generally correlates with patient's sebum production [12], but not with the degree of inflammation or the severity of acne [7, 13, 14]. However, the humoral and cellular immune responses to P. acnes correlate with acne severity. Colonization with P. acnes results in secretion of extracellular enzymes, cytokines such as IL-1a, and heat-shock proteins, all of which have mitogenic effects on T-cells [15-19]. Thus P. acnes is associated with inflammatory acne not in a concentration- dependent manner, but in an inflammation-dependent manner. Antibiotics that can both reduce the number of P. acnes and reduce inflammation by different mechanisms are therefore of utility in moderate to severe acne associated with papules, pustules, and nodules, and in acne conglobata
(Figure 1). A recent study has shown that inflammation features in the very earliest stages of acne lesion development [20]. Follicles without microcomedonal features had elevated CD3 T-cells, CD4 T-cells, and macrophages in the perifollicular and papillary dermis, as well as changes and activation of vascular intercellular adhesion molecules [20].

Oral antibiotics used in acne

Cyclines, macrolides, clindamycin, trimethoprim, co- trimoxazole, and quinolones all have efficacy in acne [21, 22]. Notably, penicillins, cephalosporins, aminoglycosides, and chloramphenicol have very limited effects in inflammatory acne [1, 23, 24].

Cyclines

Cyclines (tetracycline HCl, oxytetracycline, lymecycline, doxycycline, and minocycline) have very good efficacy in acne and generally have a good safety profile. Side effects include gastrointestinal disturbance, and some drug-specific effects discussed later in this paper. There is cross-resistance within the class, but no cross-resistance to other antibiotic classes. Cyclines are contraindicated in children under 8-12 years (varying according to national licenses) and in pregnancy due to their effect on growing bone tissue (causing inhibition of skeletal growth in the foetus and discoloration of growing teeth). Cyclines form the cornerstone of oral antibiotic therapy in acne, and are discussed in detail later in this paper.

Macrolides

The utility of oral macrolides (mainly erythromycin) in acne is increasingly limited due to the increasing problem of microbial resistance to these agents [23, 25]. Eady et al. (1989) [26] demonstrated a clear correlation between carriage of erythromycin-resistant P. acnes and poor clinical efficacy. There is frequently cross-resistance between erythromycin and clindamycin. Macrolides are therefore reserved for cases where cyclines are not tolerated, or are contraindicated (e.g. pregnancy and breastfeeding).

Clindamycin

Although effective, oral clindamycin is rarely used in acne because of potentially serious adverse effects [27]. Disturbance of gastrointestinal flora by this agent can cause overgrowth of Clostridium difficile and result in pseudo-membranous colitis. Diarrhoea is seen in 5-20% of patients using this agent [28].

Co-trimoxazole and trimethoprim

The use of co-trimoxazole (trimethoprim plus sulphamethoxazole) or trimethoprim alone is limited, and these agents are not licensed for use in acne. This is because of the potential for development of serious allergic reactions to the sulphamethoxazole component of co-trimoxazole, which may be seen in up to 3% of patients. Therefore, these agents are limited to situations where there is proven resistance to other agents or as a third-line treatment [22, 29].

Quinolones

Although one Japanese study has shown efficacy of levofloxacin in acne [30], oral quinolones are not used in acne because of the small amount of compelling efficacy data, the problems of adverse events (seen in 3-6% of patients), potential for antibiotic resistance (particularly the development of quinolone resistance in commensal bacteria [31]), high price, and unsuitability of these agents for adolescents (due to potential effects on articular cartilage) [32]. Side effects include agitation, headache, hallucination, gastro-intestinal disturbance, arthralgia, tendinitis, and photosensitivity.

MECHANISMS OF ACTION OF ANTIBIOTICS IN ACNE

Antibacterial actions

As already discussed, the density of P. acnes on the skin of acne patients does not correlate well with the degree of inflammation or the severity of acne. Similarly, the magnitude of the reduction in P. acnes counts following antibiotic therapy does not correlate well with clinical efficacy [33,34]. However, the fact that the presence of P. acnes appears to be associated with and apparently required for the formation of inflammatory lesions; that successful antibiotic treatment of acne is associated with a reduction in the P. acnes population; and that acne associated with erythromycin- or tetracycline-resistant P. acnes does not always respond as well to treatment with those agents [26,35, 36], may suggest an important role for antibacterial activity in the efficacy of antibiotics in acne. The different classes of agents exert their antibacterial effects in different ways. Cyclines, macrolides and clindamycin inhibit bacterial protein synthesis (by different mechanisms); trimethoprim and sulphamethoxazole interfere with bacterial folate metabolism; whilst quinolones inhibit bacterial DNA gyrase.

Non-antibacterial actions

Non-antibacterial actions include bacterial lipase inhibition [37-39], and anti-inflammatory/immunomodulatory effects [40-43]. P. acnes secretes lipases, which convert diglycerides and triglycerides into free fatty acids. Free fatty acids in turn cause follicular hyperkeratinisation and contribute to the clinical picture of inflammatory acne. It has been shown that cyclines and macrolides inhibit bacterial lipases, independent of their antibacterial effects [37-39].

Macrolides and cyclines also interact with the immune response in a complex way, and many different effects have been observed [40-43]. These include direct, dose-dependent inhibition of lymphocyte mitosis; inhibition of phagocytosis; decrease in the secretion of the pro-inflammatory cytokines TNF-a, IL-1 and IL-6; increase in the secretion of the anti-inflammatory cytokine IL-10; inhibition of leukotaxis; decreased activation of complement protein C3 (only noted with cyclines); modulation of a-MSH (demonstrated with minocycline); and inhibition of reactive oxygen species generation [44-47].

One of the main questions today concerning the efficacy of antibiotics in acne is to determine whether the main activity of antibiotics in acne is antibacterial or antiinflammatory. The observed efficacy of antibiotics used at low (sub-MIC) doses suggests that the non-antibacterial effects play an important role [34].

Antibiotic resistance in P. acnes

Antibiotic resistance in P. acnes was first described in 1979, when erythromycin resistance was found in a single isolate in the USA [48]. Since then, the incidence of resistance has risen, and a recent survey, conducted throughout Europe, showed that at least 50% of acne patients are colonized by erythromycin- and clindamycin-resistant strains of P. acnes, and as many as 20% are colonized with cycline- resistant strains [25].

Resistance emerges through either selection of pre-existing resistant bacterial strains, or through de novo acquisition of a resistant phenotype. Emerging antibiotic resistance in acne has been shown to develop in response to antibiotic prescribing [25]. The duration of treatment required before resistance emerges varies greatly between patients, but the longer the duration of treatment, the more likely antibiotic-resistant P. acnes will emerge, and courses of 6 months are highly likely to result in resistance.

There is a recognized correlation between the presence of antibiotic-resistant P. acnes and clinical response to treatment with erythromycin and tetracyclines (although this is less well established) [26, 35, 36]. Antibiotic resistance should therefore be considered as a possible contributory factor to, or possible cause of, therapeutic failure. High dose antibiotics will reduce sensitive strains and allow overgrowth of resistant strains in situ. However, depending on the mechanism of resistance, low dose antibiotics may also encourage overgrowth of resistant strains. In addition, low dose antibiotics may induce de novo antibiotic resistance in other commensal bacteria present (e.g. staphylococci), which often develop resistance much more quickly than resistance in P. acnes. For these reasons, the common practice of using low dose antibiotics for prolonged periods of time should not be recommended.

Antibiotic-resistant strains can be transmitted between individuals, and studies have shown that 41-85.7% of untreated close contacts of acne patients under long-term antibiotic treatment harbor erythromycin-resistant strains of P.acnes [25]. Furthermore, 25 out of 39 acne specialists tested were colonized by resistant strains, compared with 0 out of 27 non-dermatologist physicians [25]. Resistant strains can be reduced by using the topical antibacterial agent benzoyl peroxide at the site of application.

However no single available agent will fully eradicate antibiotic-resistant P. acnes.

Other ways of preventing the emergence of resistant strains include:

;1. Do not use antibiotics where other acne treatments can be expected to ;bring about the same degree of benefit.

;2. Use antibiotics according to clinical need.

;3. Do not use antibiotics as a monotherapy [5].

;4. Stop antibiotic therapy when you and the patient agree there is no ;further improvement or the improvement is only slight (one UK-based ;study suggested that 6-8 weeks into treatment might be one ;appropriate time-point at which to assess response to antibiotics [36]).

;5. Try to avoid continuing antibiotics beyond six months.

;6. Use benzoyl peroxide either concomitantly or pulsed as an
;anti-resistance agent.

;7. Do not switch antibiotics without adequate justification (i.e. re-use the ;same antibiotic for subsequent courses if patients relapse).

Risk factors for developing or acquiring antibiotic-resistant P. acnes include prolonged duration of antibiotic therapy, multiple courses of antibiotics, close contact with acne patients being treated with antibiotics, and poor compliance with treatment [25].

Topical benzoyl peroxide has been shown to be active against fully sensitive and resistant strains of P. acnes. This agent therefore reduces the likelihood of antibiotic-resistant P. acnes emerging and reduces the number of resistant bacteria in situ [49]. Other 'anti-resistance' agents include topical zinc acetate [50] and oral isotretinoin [51]. The development of antibiotic resistance can also be reduced by ensuring that antibiotics are not used unnecessarily, treatment duration is not excessively long, and patients comply well with treatment [25]. Combining therapy with topical retinoids will also expediate improvement while targeting the microcomedone [5].

In cases where antibiotic resistance is suspected, these drugs are often simply discontinued. Ideally, however, such cases should be managed by first swabbing and culturing to verify the presence of resistant strains, and then using non-antibiotic therapies such as topical benzoyl peroxide, topical or systemic retinoids, hormonal therapies, or systemic zinc salts. Raising antibiotic doses can also be considered.

THE USE OF ORAL CYCLINES IN ACNE

Pharmacokinetics

Cyclines can be classified as 'first generation' (tetracycline HCl and oxytetracycline) and 'second generation' (lymecycline, doxycycline, and minocycline). The key difference between first and second generation cyclines is their pharmacokinetic profiles (Table I). First generation cyclines must be taken at least twice daily and their absorption is impaired by food and milk, whereas second generation cyclines can be taken once or twice daily with their absorption unaffected by food. These differences may adversely affect compliance with first generation cyclines (particularly among adolescents), which may lead to therapeutic failure and the development of resistance. There are few pharmacokinetic differences between individual second generation cyclines, although it is noteworthy that only doxycycline is cleared by the liver, allowing this agent to be used in patients with renal impairment.

Efficacy

While the efficacies of first and second generation cyclines have not been compared in large randomized clinical trials, second generation cyclines have been compared in a num- ber of clinical trials (Table II) [52-57]. It can be seen that there is little to choose between these molecules in terms of efficacy, with reductions noted in the number of inflammatory lesions of 51-77% following 3-6 months of treatment. Efficacy and speed of response to treatment can be significantly improved by using topical retinoids concurrently (to target microcomedones, comedones and inflammation). In a study of 242 acne patients, a three month course of lymecycline (300 mg daily) was compared with lymecycline (300 mg daily) plus topical adapalene (0.1%) applied daily [58]. Lymecycline and combined therapy reduced the total number of lesions by a mean of 47.9% and 58.7%, respectively (P = 0.0033); inflammatory lesions were reduced by a mean of 45.6% vs 60.3%, respectively (P = 0.0001); and non-inflammatory lesions were reduced by a mean of 47.6% vs 56.6%, respectively (P = 0.01) [58]. Mobacken (1993) [54] and Campo et al. (2002) [55] exa- mined the effects of treatment for up to 6 months.

After 1 month of treatment with lymecycline (600 mg daily), Mobacken (1993) [54] found that facial papules and pustules had reduced in number by 47.5%, compared with 76.5% and 76% following a further 5 months of treatment with lymecycline at 300 mg or 600 mg daily, respectively. Thus it can be seen that additional efficacy can be gained by extending treatment with oral antibiotics beyond 1 month. Campo et al. (2002) [55] compared the efficacy of treatment with lymecycline (300 mg daily for 2 weeks, followed by 150 mg daily) plus topical adapalene, with minocycline (100 mg daily) plus topical adapalene for up to 6 months, measuring efficacy every 2 months. After 3 months, the number of acne lesions had reduced by 67% and 62% in the lymecycline and minocycline groups, respectively, compared with 77% and 67%, respectively, after 6 months of treatment. These two studies show that patients may benefit from treatment with oral antibiotics for > 1 month, but that there is little advantage in using these agents for > 3 months. In addition, the risk of developing antibiotic resistance is known to increase when treatment is continued beyond 3 months. These issues should be taken into account when considering extending treatment beyond 3 months.

Safety and tolerability

Tetracycline HCl and oxytetracycline are generally well tolerated, but can produce gastrointestinal disturbances. Like all cyclines, first generation molecules can inhibit skeletal growth in the developing foetus and cause discoloration of growing teeth (particularly with tetracycline HCl). Cyclines are therefore contraindicated during pregnancy and in young children (under 8-12 years, depending on national licenses).

Lymecycline has a good safety profile and is generally well tolerated, occasionally causing, like other cyclines, transient mild gastrointestinal disturbances, and rarely allergic reactions.

Doxycycline is noted particularly for causing photosensitivity. This effect is dependent on doxycycline dose, UVA intensity, and skin type.

Photosensitivity also greatly increases the potential for phototoxicity (burning effects and photo-onycholysis). Bjellerup and Ljunggren (1994) [59] compared the phototoxicity of doxycycline (200 mg daily) and lymecycline (1200 mg daily) using UVA light. In this study, lymecycline induced a slight increase in erythema compared with placebo at 75 J.cm-2. In contrast, doxycycline caused a highly significant increase in erythema compared with placebo at 50, 75, and 100 J.cm-2. Patients and doctors should therefore be conscious of the dangers of UVA solaria when using doxycycline, and this drug should be used with caution in hot climates during the summer. Non-comedogenic sun-screens that protect against both UVB and UVA should be considered when taking doxycycline (depending on dose and climate).

Minocycline causes a number of rare but severe side effects, including autoimmune disorders (lupus-like syndrome, autoimmune hepatitis, arthritis, thyroiditis, polyarteritis nodosa) [60-68]; and hypersensitivity reactions (pneumonitis, eosinophilia, serum-sickness-like syndrome, DRESS
[Drug Reactions with Eosinophilia and Systemic Symptoms] syndrome, arthritis, vasculitis, and hepatitis) [68]. It has been postulated that minocycline may generate a specific reactive species that could be responsable for such reactions [68]. Other effects include skin hyperpigmentation (particularly in areas exposed to the sun); single organ dysfunction (early onset, dose-related); Sweet syndrome; pseudotumour cerebri [69]; and vestibular disturbances [70]. In a review of minocycline efficacy and safety in acne, Garner et al. (2002) [64] suggested that because of a lack of proven efficacy advantages over other agents, and an uncertain safety profile, there could be no justification in continuing to use minocycline as a first line therapy in acne, and in France, the national regulatory authority (AFSSAPS) now recommends that oral minocycline should be reserved as a second choice oral antibiotic in acne.

Pharmacoeconomic considerations

One of the problems with attempting to include a cost component in developing pan-European recommendations on antibiotic use is the very large variation in drug prices across Europe (Table III. e.g. minocycline is almost three times more expensive in the UK than in Italy). For this reason, it is difficult to extrapolate data from one country to another. However, pharmacoeconomic analyses can be use- ful at a national level [71].

One recent study by Bossuyt et al. (2003) [53] compared the cost-effectiveness of minocycline (as Minocin MR®) with lymecycline (as Tetralysal 300®) for the treatment of acne in the UK, France and Belgium. In this study, 'treatment success' was defined as the percentage of patients in which acne was 'cleared', 'much improved', or 'improved'. Treatment success was similar for both agents (98.4 and 91.5% for lymecycline and minocycline, respectively, over all countries). However, 'cost effectiveness' (calculated as treatment cost divided by treatment success) was 65.89,
42.48, and 49.30 Euros per treatment success for lymecycline in Belgium, France, and UK, respectively, compared with 118.81, 80.12, and 125.33 Euros per treatment success for minocycline in Belgium, France, and UK, respectively. This study shows that lymecycline is a more cost-effective acne treatment than minocycline in Belgium, France and the UK, but particularly in the UK.

Cyclines and oral contraceptives: an interaction?

Acne patients are often concerned about the potential interaction between cyclines and oral contraceptives. Cyclines, and other broad-spectrum antibiotics, could theoretically alter the gut flora, reducing the bacterially-induced hydrolysis of steroid conjugates formed in the liver and gut wall, resulting in a decreased quantity of free steroid for reabsorption, and hence reduced plasma levels of active steroid. There have been occasional anecdotal reports of oral contraceptive failure in patients taking cyclines, and two uncontrolled retrospective studies have claimed failure rates of 1.2 and 1.4 per 100 years of therapy in patients taking cyclines [72, 73]. One controlled retrospective study examined the failure rate of oral contraceptives in 356 patients who had taken oral contraceptives and antibiotics concurrently, compared with control patients [74]. This study showed no statistically significant difference between the two groups. A recent large review concluded that available scientific and pharmacokinetic evidence does not support the hypothesis that antibiotics (with the exception of rifampicin) lower the contraceptive efficacy of oral contraceptives [75]. In addition, the American College of Obstetrics and Gynaecologists states that "tetracycline, doxycycline, ampicillin and metronidazole do not affect oral contraceptive steroid levels" [76]. The weight of this evidence suggests that oral cyclines do not interfere with oral contraceptives and that alternative forms of contraception are not necessary whilst using these agents.

Prescribing cyclines for patients with hyperseborrhoea

In a study of 255 acne patients treated for 6 months, Layton et al. (1992) [77] found a correlation between sebum excretion rate and degree of improvement in acne during treatment with erythromycin, minocycline and oxytetracycline, with higher sebum excretion rates being associated with a poorer clinical response to treatment (r = - 0.529). The authors suggest that this could be due to a reduced concentration of drug within the follicles as a result of drug dilution with sebum. Layton et al. (1992) [77] suggest that when sebum excretion rates are > 2.5 µg.cm-2.min-1, higher doses of cyclines may be required (e.g. 600 mg lymecycline daily, or up to 200 mg minocycline or doxycycline daily). When using higher doses, patients and physicians should be conscious of the increased risk of side effects (particularly with minocycline).

Conclusions

Oral antibiotics are a mainstay of treatment for moderate to severe inflammatory acne (including acne on the trunk) and, while a number of questions remain unanswered (e.g. regarding the optimal dose of antibiotic, the optimal duration of treatment and the length of maintenance therapy), there is clearly an unmet need for practical, user-friendly treatment guidelines for these drugs based on our current knowledge. The recommendations set out below provide guidance on some of the key questions regarding oral antibiotic therapy in acne (choice of oral antibiotic, doses, and duration of therapy), as well as combination therapy and maintenance therapy. By providing clear guidance that can be used in daily practice, these recommendations should improve the care of acne patients.

II. RECOMMENDATIONS FOR THE USE OF ORAL ANTIBIOTICS

Due to wide differences between published acne studies with respect to disease definitions, end-points, doses used, duration of treatments etc., as well as the many unanswered questions that require further investigation, it is not currently possible to derive definitive treatment guidelines backed up by high quality evidence. The recommendations below should therefore be viewed as guidance based on expert opinion of the available data.

These recommendations are intended to provide improved patient benefit, and are based on analyses of efficacy, resistance, safety, cost effectiveness, expert opinion, and the needs and limitations of daily practice.

First choice of antibiotic

; 1.  Based on advantages in efficacy, safety, and antibiotic resistance,
; cyclines should be used in preference to other classes of antibiotics in
; the treatment of acne.

;2.  Based on pharmacokinetic advantages, second genera- tion cyclines should be used in preference to first generation cyclines.

;3.  Based on side effect profiles*; lymecycline and doxycy- cline should be ;used in preference to minocycline. The choice of agent will depend on
  the patient characteristics, season, UV exposure and country.

Cycline doses

;1.  Lymecycline should be used at a dose of 300-600 mg daily.

;2.  Minocycline and doxycycline should be used at a dose of 100-200 mg
  daily**.

;3.  Tetracycline HCl and oxytetracycline should be used at a dose of 1 g
  daily.

Duration of treatment

;1.  According to the available literature, oral antibiotics should be used for
  3 months. In clinical practice, they may be continued longer until clinical
  improvement is achieved.

;2.  If oral antibiotics are used for prolonged periods***, they should only
;be continued where further clinical benefit is likely, and should always
  be used in combination with an agent that reduces the likelihood of
  propionibacterial resistance emerging (e.g. benzoyl peroxide).

;3.  Compliance should be checked in patients who do not respond well to
  therapy.

Combination therapy

;1. Oral antibiotics should not be used alone (as this will target only two
  pathophysiologic factors of acne).

;2. Oral antibiotics should be combined from the start of treatment with
  a topical retinoid (this will target three pathophysiologic factors of acne,
  as well as the microcome- done [the precursor of all acne lesions]).

;3. Benzoyl peroxide can be used in combination with topical retinoids
  and oral antibiotics, and should always be considered for patients
  receiving oral antibiotics for more than 3 months.

;4. Oral antibiotics should not normally be combined with topical
  antibiotics (this may increase the risk of P. acnes resistance and
  provides no additive benefit).

* Lymecycline: rare side effects; doxycycline: rare side effects, but dose-
  dependent phototoxicity; Minocycline: rare but severe side effects.

**200 mg should be reserved for special cases such as hyperseborrhoea,
  and patients and physicians should be aware of potential side effects
  at this dose.

*** Studies have shown most improvement occurs within the first 4
  months of treatment.

Maintenance therapy

;1. Maintenance therapy should be considered in order to limit relapse.
  Optimal duration and dosing remains undetermined.

;2. Topical retinoids are the treatment of choice for maintenance therapy.

;3. Maintenance therapy should be continued for as long as individually
  needed (this recommendation is not currently evidence-based).

;4. Benzoyl peroxide can be added to topical retinoids if necessary (to
  decrease the number of antibiotic-resistant P. acnes).



EJD, vol. 14, n° 6, November-December 2004

Page Created: 7 February 2006