doxycycline

Overview

Doxycycline is a broad-spectrum tetracycline-class antibiotic used in therapy for a range of bacterial infections and inflammatory conditions. It acts primarily by inhibiting bacterial protein synthesis through binding to the 30S ribosomal subunit, which makes it active against many Gram-positive and Gram-negative organisms as well as atypical pathogens. In clinical practice, doxycycline is also valued for its oral bioavailability, tissue penetration, and utility as an alternative when other antibiotics are unsuitable.

Beyond its antimicrobial role, doxycycline is frequently studied as a platform drug in drug-delivery systems and localized formulations. Recent research contexts also reflect interest in its anti-inflammatory and tissue-modulating properties, including applications in periodontal disease and experimental prevention strategies for sexually transmitted infections. Its use in children and in combination regimens continues to be evaluated, particularly where macrolides such as azithromycin are standard comparators.

Focus of Latest Publications

Recent publications have examined doxycycline in several therapeutic and translational settings.

One study investigated novel cyclodextrin-siderophore conjugates as a Trojan horse strategy for bacterial targeting, specifically evaluating these derivatives as doxycycline carriers in Escherichia coli and Staphylococcus aureus. This work places doxycycline in the context of siderophore-based drug delivery, aiming to improve bacterial targeting through conjugation strategies rather than relying on conventional free-drug exposure.

In pediatric respiratory infection research, doxycycline was the intervention under evaluation in the DOMINO trial protocol, a multicentre, randomised, open-label, superiority study comparing doxycycline with azithromycin for children with pneumonia suspected of macrolide-resistant Mycoplasma pneumoniae infection. The protocol highlights doxycycline as an effective alternative to macrolides, while also noting that its use in young children has historically been limited because of concerns about tooth discolouration. No efficacy results were reported in the protocol itself, but the study was designed to assess both safety and effectiveness.

Doxycycline also appeared in a case report of culture-negative infective endocarditis presenting as ANCA-positive glomerulonephritis, where the patient was treated with doxycycline and rifampin for 12 weeks and subsequently showed clinical and laboratory improvement. In this context, doxycycline was part of a prolonged combination regimen associated with recovery.

In infectious disease prevention research, topical inserts containing doxycycline were formulated at 10, 50, and 100 mg doses for bacterial sexually transmitted infection prevention. This work suggests interest in doxycycline as a locally delivered prophylactic agent, potentially reducing systemic exposure while maintaining antimicrobial activity.

Doxycycline has also been incorporated into a dissolving microneedle platform for periodontal therapy. A miR-126 nanoparticles@doxycycline dissolving microneedle patch was developed for localized co-delivery of miR-126 nanoparticles and doxycycline to gingival tissue, with the aim of achieving anti-inflammation and periodontal tissue regeneration. This study positions doxycycline as part of a combined immunomodulatory and regenerative strategy, rather than as a stand-alone antimicrobial.

Another case report described reversible subacute secondary parkinsonism due to neuroborreliosis, where treatment with intravenous ceftriaxone followed by oral doxycycline led to rapid improvement. Here, doxycycline served as oral step-down therapy after initial parenteral treatment.

Finally, doxycycline was referenced in aging and mitochondrial biology research as a comparator-like compound: terbinafine and miglustat were reported to activate mitochondrial stress responses and modulate mitochondrial function across species similarly to doxycycline. This indicates that doxycycline remains relevant in studies of mitochondrial stress pathways, even outside its direct antimicrobial indications. The same publication context also mentioned mitochondrion-related pathways, underscoring doxycycline’s broader experimental use in cellular stress research.

Key Publications

• Jun Cyclodextrin-siderophore conjugates as a Trojan horse strategy for bacterial targeting. (Journal of inorganic biochemistry, 2026, PMID 41724131): "These novel derivatives were investigated as doxycycline carriers in the bacteria Escherichia coli and Staphylococcus aureus."
• May Efficacy and safety of Doxycycline versus Macrolides for Mycoplasma pneumoniae INfectiOn in Children (DOMINO): a protocol for a multicentre, randomised, open-label, superiority trial. (BMJ open, 2026, PMID 42191206): "This study aims to evaluate the efficacy and safety of doxycycline compared with azithromycin as a first-line treatment for children with pneumonia suspected of MRMP infection."
• May Formulation Development of Topical Inserts Containing Doxycycline and Doxycycline Combined with Tenofovir Alafenamide and Elvitegravir for the Prevention of Sexually Transmitted Infections. (AAPS PharmSciTech, 2026, PMID 42091755): "We have formulated two different inserts, one containing doxycycline (DOX) at 10, 50, and 100 mg doses for bacterial STI prevention."
• May Versatile Microneedle Platform for Localized Immunomodulatory Therapy of Periodontitis Targeting the Reactive Oxygen Species/NF-κB Pathway. (ACS nano, 2026, PMID 42007801): "Herein, we developed a miRNA-126 nanoparticles@doxycycline dissolving microneedle patch (miR-126 NPs@DOX MN) for localized codelivery of miRNA-126 nanoparticles (miR-126 NPs) and doxycycline (DOX) to gingival tissue, aiming to achieve anti-inflammation and periodontal tissue regeneration."
• May Culture-Negative Infective Endocarditis Presenting as ANCA-Positive Glomerulonephritis. (The American journal of case reports, 2026, PMID 42107047): "The patient was treated with doxycycline and rifampin for 12 weeks, resulting in clinical and laboratory improvement."
• May Reversible subacute secondary parkinsonism due to neuroborreliosis with characteristic MRI evolution. (BMJ case reports, 2026, PMID 42055759): "Treatment with intravenous ceftriaxone followed by oral doxycycline resulted in rapid improvement."
• Apr Targeting Mitochondrial Stress Responses: Terbinafine and Miglustat as Novel Lifespan and Healthspan Modulators. (Aging cell, 2026, PMID 41913053): "Terbinafine and miglustat robustly activated the mitochondrial unfolded protein response (UPRmt) mediator ATFS-1, upregulated MSR pathways, and modulated mitochondrial function across species, similarly to doxycycline."