Image Gallery: Minocycline‐induced photo‐onycholysis with pigmentation

Long-Term Safety Profiles of Macrolides and Tetracyclines: A Systematic Review and Meta-Analysis

Macrolides and tetracyclines are antibiotics that have a range of anti-inflammatory properties beyond their microbial capabilities. Although these antibiotics have been in widespread use, the long-term safety profiles are limited. We performed a systematic review and meta-analysis of randomized clinical trials that compared macrolides or tetracyclines with placeboes to provide long-term safety information. We searched Medline and EMBASE from inception to October 2022 and identified studies that reported study drug-related death, serious adverse events (SAEs), or withdrawal rates, and common adverse effects of each drug. Relative risk (RR) and number needed to harm were calculated. Of the 52 randomized clinical trials included, there are 3151 participants on doxycycline, 2519 participants on minocycline, 3049 participants on azithromycin, 763 participants on clarithromycin, 262 participants on erythromycin, and 100 participants on roxithromycin. There was no death related to any study drugs and rates of SAE were not significantly different from placebo in any drug. Overall withdrawal rates were slightly higher than placebo in doxycycline (RR, 1.30; 95% CI, 1.12-1.52) and minocycline (RR, 1.29; 95% CI, 1.15-1.46). Withdrawal rates due to adverse events were higher in doxycycline (RR, 2.82; 95% CI, 1.88-4.22), minocycline (RR, 1.48; 95% CI, 1.09-1.98), and azithromycin (RR, 1.53; 95% CI, 1.13-2.08). Gastrointestinal disturbances are the most common tolerable adverse effects for every drug. Photosensitivity and rash are the second most common adverse effects for doxycycline and minocycline. We found no evidence that long-term use up to 2 years of macrolides or tetracyclines was associated with increased risk of SAEs.

Characterization of the Interactions between Minocycline Hydrochloride and Trypsin with Spectroscopic and Molecular Docking Technology

In the current study, the interaction of minocycline hydrochloride (MC) and trypsin (TRP) was studied using fluorescence spectroscopy, synchronous fluorescence spectroscopy, three-dimensional fluorescence spectroscopy, UV-Vis spectroscopy, and molecular docking simulation techniques. The results show that the fluorescence quenching of trypsin at different degrees can be caused by minocycline hydrochloride at different temperatures. According to the Stern-Volmer equation, the fluorescence quenching type was static quenching. By calculating critical distance, we concluded that there is a possibility of non-radiative energy transfer between minocycline hydrochloride and trypsin. The effect of minocycline hydrochloride on the secondary structure of trypsin was demonstrated using ultraviolet spectroscopy. Synchronous fluorescence spectroscopy showed that minocycline hydrochloride could bind to tryptophan residues in trypsin, resulting in corresponding changes in the secondary structure of trypsin. Three-dimensional fluorescence spectroscopy showed that minocycline hydrochloride had a particular effect on the microenvironment of trypsin that led to changes in the secondary structure of trypsin. The molecular docking technique demonstrated that the binding of minocycline hydrochloride and trypsin was stable. Circular dichroism showed that the secondary structure of trypsin could be changed by minocycline hydrochloride.