Aggregation of data from 4 clinical studies demonstrating efficacy of single-dose doxycycline postexposure for prevention of the spirochetal infections: Lyme disease, syphilis, and tick-borne relapsing fever

Safety of Longer-Term Doxycycline Use: A Systematic Review and Meta-Analysis With Implications for Bacterial Sexually Transmitted Infection Chemoprophylaxis

BACKGROUND

Sexually transmitted infections (STIs) such as syphilis, gonorrhea, and chlamydia have significantly increased over the past decade in the United States. Doxycycline as chemoprophylaxis (i.e., postexposure prophylaxis) offers promise for addressing bacterial STIs. The goal of the current study was to evaluate the safety of longer-term doxycycline use (defined as 8 or more weeks) in the context of potential use as STI chemoprophylaxis through a systematic literature review and meta-analysis.

METHODS

This review used the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines to search MEDLINE/PubMed for clinical studies published from August 2003 to January 2023 that reported on adverse events with doxycycline use with a focus on side effects and metabolic effects of long-term use.

RESULTS

A total of 67 studies were included in the systematic review. Overall, studies on longer-term doxycycline use reported 0% to greater than 50% adverse events ranging from mild to severe. Most common adverse events included gastrointestinal symptoms (i.e., nausea, vomiting, and abdominal pain), dermatologic (i.e., rash), and neurological (i.e., headache and dizziness) symptoms. Discontinuation of doxycycline due to adverse events was relatively uncommon in most studies. A meta-analysis of placebo controlled clinical trials (N = 18) revealed that gastrointestinal and dermatological adverse events were more likely to occur in the doxycycline group.

CONCLUSIONS

Longer-term (8+ weeks) doxycycline use is generally safe and may be associated with minor side effects. Further research is needed on the potential metabolic impact of longer-term doxycycline use.

Lyme Disease and Post-treatment Lyme Disease Syndrome: Current and Developing Treatment Options

Lyme disease and its treatment implications have become an ever-increasing area of concern within the United States related to the markedly increased prevalence of infection within the last two decades. The presentation, pathophysiology, and epidemiology of Lyme disease have been well studied, and thus treatments for this disease are widely available. While the treatment of its early and late stages is relatively simple with 10-14 day and four-week courses of doxycycline, respectively, the main problem rests in the understanding of the etiology and pathology of post-treatment Lyme disease syndrome (PTLDS). With the time of symptoms onsetting approximately six months after treatment and potentially lasting indefinitely, this syndrome's effect on patients' quality of life could be devastating. Searching on PubMed, Google Scholar, MEDLINE, and ScienceDirect using keywords including Lyme disease, PTLDS, doxycycline, erythema migrans, azlocillin, and treatment, the authors have tried to make clear the different aspects. The authors have reviewed and discussed clinical studies of Lyme disease and its treatments/potential therapeutics as well as PTLDS and its sparse treatments/potential therapeutics.

Antibiotic prophylaxis for prevention against Lyme disease following tick bite: an updated systematic review and meta-analysis

Background

In areas where Lyme disease is endemic, bites from ticks are common, but no vaccine is currently available against Lyme disease for humans. Therefore, the feasibility of using antibiotic prophylaxis to prevent Lyme disease after a tick bite is worth further exploration. Previous meta-analyses lack sufficient power to demonstrate the efficacy of about antibiotic prophylaxis for the prevention of Lyme disease following a tick bite. In this study, we explored more precise evidence and attempted to identify and update optimum treatment strategies.

Methods

We searched PubMed, Embase, and the Cochrane Library for studies until March 23, 2021. We included studies if the enrolled patients were randomly allocated to a treatment or control group within 72 h following a tick bite and had no clinical evidence of Lyme disease at enrolment. The Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) reporting guidelines were followed for data abstraction. Two authors (GZZ and XX) independently reviewed the abstracts and identified articles for detailed assessment. We used a random-effects model to calculate the pooled results and reported the 95% confidence interval (CI). Study quality was assessed using a modified Jadad scale, and publication bias was assessed using Egger’s test. We calculated the risk ratio (RR) for the rates of unfavorable events in patients who received intervention versus the control group. This study is registered with PROSPERO, number CRD42021245002.

Results

Six studies (3,766 individuals) were included. The pooled rate of unfavorable events in persons receiving treatment and the control group were 0.4% (95%CI: 0.1–1.1%) and 2.2% (95%CI: 1.6–3.0%), respectively. The pooled RR was 0.38 (95%CI: 0.22–0.66). Subgroup analysis revealed that the pooled RR was 0.29 (95%CI: 0.14–0.60) in the single-use 200-mg doxycycline group; 0.28 (95%CI: 0.05–1.67) in a 10-day course group (Amoxicillin, Penicillin or tetracycline); and 0.73 (95%CI: 0.25–2.08) in a topical antibiotic treatment group (Azithromycin).

Conclusions

The available evidence supports the use of antibiotics for the prevention of Lyme disease, and reveals advantages of using single-dose; however, further confirmation is needed.