Maximum Effective Dose of Doxycycline is 40mg a Day

Written by on September 10, 2007 in doxycycline, Galderma, Oracea (40mg doxycycline) with 2 Comments

There has been a lot of copy written about so-called low dose or anti-inflammatory dose doxycycline. This form of antibiotic therapy is one of the more promising recent therapeutic developments ; it will likely become a widely known and available treatment.

This recently published paper shows that a daily dose of 40mg of doxycycline is as effective in reducing the lesions of rosacea as a higher dose of 100mg or 200mg a day.

Note that this is a statistical study using existing clinical trial data, and that the authors work for Collagenex, who were bought by Galderma. Galderma are the makers of Oracea.

Great Publicity Opportunity

This result is a great result for the marketability of Oracea – you don’t need to take a higher dose of doxycycline, just take Oracea – or so the story goes.

Anti-Inflammatory Dose Doxycycline (40 mg Controlled-Release) Confers Maximum Anti-Inflammatory Efficacy in Rosacea.

. 2007 Sep-Oct;6(5):221-6., Theobald K, Bradshaw M, Leyden J., CollaGenex Pharmaceuticals Inc, Newtown, PA.

Background. Two large clinical trials have recently demonstrated the efficacy of a 40-mg controlled-release formulation of doxycycline in the treatment of rosacea, a dose well below the conventional level of 100 to 200 mg/d. Since no formal dose-response studies have been conducted, the authors analyzed phase 3 data to determine whether a dose-efficacy relationship exists.

Methods. Standard parametric regression analyses were used to estimate the correlations between dose (mg/kg body weight) and overall drug exposure (area under the curve [AUC]) in a phase 1 pharmacokinetic study and between dose and efficacy (mean change from baseline in total inflammatory lesion count at week 16) in 2 pooled phase 3 clinical efficacy studies. Additional regressions were run at each visit for the clinical efficacy studies to determine whether results differed across visits. A regression analysis was also performed in a subset of patients who showed a greater efficacy response.

Results. We found overall drug exposure (AUC) to have a highly significant correlation with dose (mg/kg) (r=0.49; P=.006). In contrast, clinical efficacy did not correlate with dose at any of the visits at week 3 (r=0.01; P=.85), week 6 (r=0.04; P=.53), week 12 (r<0.01; P=.98), and week 16 (r=0.03; P=.64) or among the subset of patients who showed greater clinical benefit.

Conclusions. Higher mg/kg doses led to higher plasma concentrations but did not lead to increased clinical efficacy. Anti-inflammatory dose doxycycline (40-mg controlled-release formulation) conferred peak anti-inflammatory efficacy in the treatment of rosacea.

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About the Author: David Pascoe started the Rosacea Support Group in October 1998. .

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2 Reader Comments

  1. ludi says:

    I am a rosacea sufferer. I immigrated from South Africa to Australia In SAfrica i uses Tetralysal which was very effective for the condition. In Austalia the docters prescribed doxycyline 50 mg a day. It doesn’t work at all. I need to fly back to SAfrica every year to get the medicine there. I am desperate to find a less costly solution in Australia as doxycycline seems ineffective.

  2. Hi Ludi,

    Doxycycline works well for the papules and pustules of rosacea, is that what you are taking it for ? It is a tetracycline, like I imagine Tetralysal is also. At 50mg a day I would expect it to take up to 6 weeks to see a benefit. The advantage of such a small dose is that it won’t likely give some of the other side effects of higher doses.


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