What effect does minocycline have on nails?

Minocycline, a tetracycline antibiotic, is known to have a side effect that can lead to a characteristic pigmentation change in various tissues. One of the notable effects of minocycline use is the staining of nails, as well as skin and other tissues, resulting in a blue-grey discoloration. This is due to the drug's ability to bind to the tissues and subsequently alter the pigmentation.

The blue-grey color induced by minocycline occurs because of the accumulation of the drug or its metabolites in the nail matrix or other tissues, which changes their normal appearance. This effect is similar to that seen in other parts of the body, where minocycline can cause pigmentation changes.

While other options might appear plausible, they do not accurately reflect the established effects of minocycline on nails. For instance, minocycline does not increase nail growth rate or make nails more resilient; rather, it can lead to undesirable pigmentation alterations.