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Medical AI Inquiry: You were designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.
user
A 17 years old girl with acne has been taking a drug for the last two years. She now presents with blue black pigmentation of nails. The likely medication causing the above pigmention is –
assistant
The correct answer is  Patients taking minocycline may develop a diffuse blue - grey, muddy appearance in sun exposed areas in addition to pigmentation of mucus membranes, teeth, nails, bones and thyroid.
Amongst tetracyclines two side effects unique to minocycline are drug induced lupus and blue black pigmentation.