Hello. Thanks for writing to us at healthcaremagic Microdox-LBX is doxycycline and is a commonly prescribed oral antibiotic for inflammatory acne. It is available in 100 mg strength both as tablets and capsules form. The dose is once or twice daily depending on the severity of inflammatory acne. The recommendation is that it can be prescribed for up to 8-12 weeks continuously, if need be, depending on the severity of acne. However, since acne is a recurrent condition therefore repeated courses may be required. The recommendation is to take it in daily doses rather than on alternate days. Taking it irregularly or on every alternate days poses a definite risk of developing bacterial resistance. Nevertheless, It should always be taken under the supervision of a dermatologist. The mechanism of its action in acne is not antibacterial but rather anti-inflammatory and even daily low doses of 40 mg have been used for its anti-inflammatory action. However, the dosage is once daily to maintain the anti-inflammatory effect in continuity At these low doses it does not pose any risk of microbial selection because this dose is below the minimum inhibitory concentration (MIC) levels of most bacteria and therefore there are no chances of bacterial resistance. I would suggest that you seek another appointment with your dermatologist and discuss in more details. Regards