DOXY PEP

What is DOXY PEP?

Doxy PEP is a new study which done over 1 year. DOXY is short for the antibiotic drug called DOXYCYCLINE and PEP is a ACRONYM for Post Exposure Prophylaxis. So, DOXY PEP is an antibiotic drug which is used as a post sexual contact protection against certain sexually transmitted disease. It has a similar effect like the POST EXPOSURE PROPHYLAXIS against HIV.

Understand that not everyone should be on DOXY-PEP.

WHAT IS THE DOXY PEP STUDY ABOUT?

This is a study which is done in California, America. They did this study to limit the cost and manpower to justify the usage of Doxycycline as post-exposure protection. There are many other research in other parts of the world which may disprove the usage of DOXY-PEP.

WHAT IS THE OBJECTIVE OF DOXY PEP?

This is a randomized study to assess the efficacy and safety of doxycycline in MSM and transgender women who are either on PrEP or not on PrEP (Pre-Exposure prophylaxis Against HIV) and another special group including people living with HIV (PLWH). This study included 

HOW IS DOXY PEP STUDY CONDUCTED?

501 participants were randomly assigned. 327 participants on PrEP and 174 participants who are PLWH. From the total of 501 participants there were randomized into 2 groups; the with DOXY PEP group and Standard care group (without DOXY PEP). Both groups are divided in a ratio of 2:1 which translates into 334 participants with DOXY PEP and 167 participants without DOXY PEP. 

With DOXY PEP (p=334)

RESULTS

Without DOXY PEP (p=167)

570 visits from the PrEP cohort. 61 visits out of the total 570 visits developed STI with the use of DOXY PEP

Number of visits for STI checking from the PrEP cohort & diagnosed with STI

257 visits from the PrEP cohort. 82 visits out of the total 257 visits developed STI without the use of DOXY PEP

305 visits from the PLWH cohort. 36 visit out of the total 305 visits developed STI with the use of DOXY PEP.

Number of visit for STI checking from the PLWH cohort & diagnosed with STI

128 visits from the PLWH cohort. 39 visits out of the total 128 visits developed STI without the use of DOXY PEP

875 visits from the PrEP and PLWH cohort

Total visit

385 visits from the PrEP and PLWH cohort

Out of 875 visits there were 97 visits developed STI 

Total STI cases with or without DOXY PEP

Out of 385 visits there were 121 visits developed STI. 

11.08% had STI with DOXY PEP

Percentage of incidence in the DOXY PEP and the without DOXY PEP cohort.

31,2% had STI without DOXY PEP.

CONCLUSION： The combined incidence of gonorrhea, chlamydia and syphilis was lower by two thirds with DOXY PEP than with the standard care (Without DOXY PEP)

Discuss with your doctor before starting DOXY-PEP. It may not be suitable for everyone.

WHAT ARE THE CONSIDERATIONS  WHICH LEAD TO THE STUDY OF DOXY-PEP?

This is an unspoken consideration of DOXY to be used as PEP. This situation is similar to the study of PrEP on Demand. These two studies are done in the USA and there are other considerations which led to these studies. These considerations mainly fueled against cost and workload of medical personnels. Health care in the USA is falling apart similar like the UK with high cost and long waiting time to be seen by a physician. 

The situation is rather dire in which patients with STI are required to schedule an appointment which may be about 1 month apart. By the time the patient sees a doctor and to get tested, the patient may already experience complications of untreated or slow to treat STI due to the health system failure. Therefore initiating DOXY-PEP may be prudent to start their population on treatment as soon as possible without regards to antibiotic resistance, STI  symptoms or complications and in their efforts to "buy time" for the patient from the time of onset of symptoms to the time of their doctor's appointment.

Furthermore, by starting DOXY-PEP the symptoms and complications of STI maybe reduced which will result in reduced cost of treatment. In a nut-shell: DOXY PEP actually reduces cost generally but may result in other problems which needs to be discussed under the subtitle "IS THERE A GOOD CONSENSUS FOR THE USAGE OF DOXY PEP?"

Most people can have STI without any symptoms but it does not mean they do not have STI. Take this personal experience of mine; I was training my new staff members and showed them the proper technique to take oral swab and I had a shock when my test was reactive for gonorrhea. I did not have any symptoms of oral gonorrhea like sore throat or exudative tonsillitis and have not fallen ill for more than 5 years. This means that "No Symptoms does not equal to No STI". 

As DOXY PEP is rolled out, this also prevents people to have a false sense of security and do not test for STI as frequent as necessary. DOXY-PEP may mask symptoms because taking DOXY after sexual contact may cause partial treated STI. This means in layman's term; DOXY killed some but not all the STI causing bacteria and results in asymptomatic STI in most cases and / or increase drug resistance.

Like I said, this an unspoken situation when these studies are conducted to reduce cost. This same situation occurs in  Pre-exposure Prophylaxis (PrEP) against HIV. Initially, PrEP was on daily basis and to cut back on cost; a study was conducted which resulted in the formulation of PrEP on demand. Daily PrEP requires the user to use PrEP everyday but PrEP on demand only which requires only 4 pills per sexual contact, therefore reduces the cost. PrEP on demand is another USA study which involved only the USA population.

The results of the study may be different if they included other populations like Asians, Europeans and Africans. Medications may affect different populations differently; take for example anti-hypertensive medications. There are 4 classes of medications named in alphabetical order (A) ARB-Inhibitor or ACE-inhibitor, (B) Beta-blocker, (C) Calcum channel-blocker and (D) Diuretics. Sutdies shows that asians and caucasians have higher effectiveness with (A) group of drugs as compared to (C) groups of drug. Africans have better efficacy in lowering their blood pressure with (C) group of drugs. 

The study conducted in Kenya for DOXY－PEP has already shown low effectiveness in Kenyan population to reduce STI. There are other studies in other countries which offer very different inconsistent results and outcomes when DOXY is used as PEP. With this analogy in mind; ask yourself "Does it mean that PrEP on demand or in our discussion about DOXY-PEP will be effective in every population?"

Conclusion:

1. DOXY-PEP may not be suitable as post-exposure prophylaxis in all STI cases. 

2. Each population had different outcome discrepancies in the efficacy of DOXY-PEP. 

3. DOXY-PEP is not a wonder drug for all STI. 

4. DOXY-PEP needs to be used judicially.

5. DOXY－PEP can cause other issues like drug resistance.

IS THERE A GOOD CONSENSUS FOR THE USAGE OF DOXY PEP？

The Australian Society for HIV Medicine (ASHM) published an abstract of DOXY PEP among gay, bisexual and men to men sex（GBMSM). The broad agreement that doxy-PEP should be considered primarily for the prevention of syphilis in GBMSM. At the end of the consensus process, there remained some disagreements, as some strongly felt that doxy-PEP could increase antimicrobial resistance as it outweighs any potential benefit from reduction in other bacteria STI in the GBMSM population. Unlike HIV PrEP and PEP, doxy-PEP may not be suitable as population-level intervention and should be used more judicially. 

WHAT ARE THE PITFALLS OF DOXY PEP?

Each country has different outcomes in each respective study:

1. IPREGAY trial from France reported a 47% STI reduction in DOXY-PEP in MSM on PrEP. Relative reduction was almost 70％ for Chlamydia trachomatis and Syphlis but no reduction in N. Gonorrhea due to drug resistance.
   

2. DOXYVAC trial is another study from France with 84% reduction of Chlamydia trachomatis and 51% reduction in N. Gonorrhea. 
   

3. DOXYPEP trial from the US shows there is 77% reduction of syphlis and 74% reduction of chlamydia. DOXYPEP showed reduction of N. Gonorrhea to 55%. There are inconsistent finding of DOXYPEP reduction N. gonorrhea at 55% if compared with the France study which show no reduction of N. Gonorrhea. The argument is that there is more drug resistance in the French population as compared to USA population. Therefore, in France there is no reduction of N. Gonorrhea incidence even on DOXYPEP. 
   

4. South African MSM had about 70-80% reductions in chlamydia and syphilis. Gonorrhea had about 50% reduction. However, DOXY-PEP was not effective in reducing Chlamydia and Gonorrhea in Kenyan cisgender women. It is perplexing when we look at the data between the effectiveness of DOXY-PEP between MSM and cisgender women in Kenya. Why does gender and sexuality affect the outcome and results of the study? All studies had same outcome of antimicrobial resistance for DOXY-PEP. All these studies are all conducted in a short period of about 1 year and requires further long-term assessment to see the benefits versus the risk. According to the research in Kenya, it is claimed that the effectiveness of DOXY PEP is poor because of the poor compliance of Kenyan women in using DOXY PEP. and requires further debate and discussion with concrete evidence.

   
   
   
   

HOW DOES DOXY PEP FARE AGAINST DRUG RESISTANCE？

The incidence for drug resistance is always high when it comes to uncontrolled usage of antibiotics. With the emergence of DOXY PEP as a protocol by the United States of America, it is causing a lot of harm than good. The reasoning is simple. Everyone in this world has numerous bacteria and by starting DOXY PEP we are indirectly training all bacteria in and on your body to learn to adapt against antibiotic (DOXY PEP). In between, bacteria there is also an exchange of new genetic material which also may contain the adapted gene of resistance against DOXY PEP and other antibiotics.

You will be wondering the reason about my hesitancy to use DOXY PEP. Drug resistance in DOXY PEP should be a concern in the medical community. Drug resistance is a condition when the bacteria become stronger than the antibiotics due to recurrent and unjudicial repeated usage of antibiotic, thus causing emergence of drug resistance. DOXY PEP is a poorly designed study and due to the data, which shows promise of prevention of Syphilis, and Chlamydia only, therefore people are misusing DOXY PEP as a so called prevent all sexually transmitted disease, which is totally the wrong concept. The DOXY PEP is considered a poorly designed study because the objective is aimed to reduce cost burden in the short term to prevent some sexually transmitted disease namely Syphilis and Chlamydia only. DOXY PEP does not work on Gonorrhea at all in the study and the study failed to check for effectiveness against Ureaplasma Urealyticum, Ureaplasma Parvum, Mycoplasma Genitalium and Mycoplasma Hominis; which is also a common sexually transmitted disease.

DOXY PEP drug resistance should be a medical national concern, however doctors who do not understand the significance of the DOXY PEP study and who are unable to appraise the DOXY PEP study should not advising their clients or patient to use DOXY PEP indiscriminately and ubiquitously. 

Resistance to tetracycline class of antibiotic. DOXYPEP in South Africa has reported that 74-89% of N. Gonorrhea strains has developed two mutations putative tet(M) an V57M which causes the rise of resistance of DOXYPEP and Tetracycline. DOXYPEP can also be used against M. genitalium which is another STI susceptible to doxycycline but there has been history of rapidly acquiring resistance mutation in this particular infection. Now it is recommended to have a sequential therapy of doxycycline followed by azithromycin or moxifloxacin to prevent further emergence of drug resistance. This makes the course of treatment more prolonged and complex.  

Drug resistance is when certain pathogens gain immunity against antibiotics.

Disruption of microbiome is one other problem which occurs in the DOXYPEP population. Microbiome are commensal bacteria which populates the throat, lungs, skin and gut. In general this commensal bacteria already exist in those areas as indigenous species of bacterial and can never be eradicated fully even with long courses of antibiotics. In the DOXYPEP study, it was noted that there is a reduction of nasopharyngeal S. Aureus from 42% to 29% but with drug resistance occurrence from 4% to 12% which is a 3 fold increment.

DOXY-PEP is not effective against gonorrhea

DOXYPEP also reported a persistently high >80% of other species of Neisseria in the nasopharynx. I will simply the abstract of this situation. Neisseria is a species of bacteria, it is similar like humans who carries a family name and under that family name there are siblings with different given names. Take for example: the Gui (My chinese family name) family, there is Jonathan Gui, Barnard Gui, Sharon Gui and Josephine Gui, each of them carry the same family name but different given name. This is similar in the species of bacteria, there is Neisseria Gonorrhea, Neisseria Ovale, Neisseria Meningitis, Neisseria Canis and about 20 other types of Neisseria. So DOXYPEP will not be effective against the other types of Neisseria as prolonged usage of DOXYPEP disrupts the microbiome.   

Short duration of all studies related to Doxycycline being used as post-exposure prophylaxis against STI. The longer the study is conducted the more data can be collected and analyzed more accurately. The problem of these studies only lasted about 1 year and was discontinued. Whether, there is going to be emergence of DOXYCYCLINE resistance or not, we have to investigate further. Drug resistance is always fast paced therefore, doxycycline must be used cautiously.

Each country or organization has a set of different consensus:

1. The San Francisco Public Health Unit, the California Department of Public Health and the Public Health Seattle & King country in the US recommend Doxycycline as PEP by MSM (Mn sex men) and TGW (transgender women)
   

2. Center for Disease Control and Prevention (CDC) provided consideration to healthcare provider to inform decision-making on a case-by-case basis. 
   

3. The British Association for Sexual Health and  HIV and the United Kingdom (UK) Health Security Agency do not endorse Doxycycline for STI prophylaxis for lack of data about antimicrobial resistance.
   

4. World Health Organisation (WHO) has not issued any statement about DOXYPEP for STI prevention.
   

5. The Australasian Society for HIV, Viral Hepatitis and Sexual Health Medicine in 2023 has come to their own consensus which puts the ball back to the health care provider to justify the use of DOXYPEP in a case-to-case basis with a list of criterias.

WHY IS DRUG RESISTANCE IS HIGHER IN DOXY-PEP & LESSER IN PEP FOR HIV PREVENTION？

The reason is so obvious. Take for example the situation with COVID emergence of newer strains was so fast that scientists could not catch up with the number of new strains emerging. Why do you think the new strains appears so fast? COVID was infecting almost everyone. Due to the large population of infected host subjects, this causes faster cross mutation and fast emergence of newer strain.

In similar condition everyone has bacterial infections but not everyone has HIV. Therefore, the incidence drug resistance is always higher in bacterial infections and emergence of newer strains due to cross of bacterial strains. These cross of bacterial strains occurs more frequently as compared to HIV. The cross of bacterial strains is when the same bacterial species exchange genetic material and so called "experiences of exposure to antibiotics". In a way when humans interact with other humans, exchange information and experiences so that we can learn from past mistakes.

WHAT ARE THE DIFFERENCES OF THE USA, CALIFORNIA DOXYPEP VERSUS THE AUSTRALIASIAN SOCIETY CONSENSUS OF DOXYPEP?

According to the Australiasian Society; recommend avoiding multiple doses. Take for example, a person is active over the weekend therefore the person should not be taking DOXYPEP on Friday, Saturday and Sunday. Rather DOXYPEP should be initiated on Monday before the 72 hours from first initial contact (Friday contact). This is to limit the frequent usage of DOXYPEP which may result in drug resistance.

According to the USA, California protocol if a person who is active over the weekend they should initiate DOXYPEP on Friday, Saturday and Sunday on the day of post intercourse. This protocol increase the usage of DOXYPEP to more frequent dosage which can cause higher possibility of drug resistance against DOXYCYCLINE.

It makes perfect sense in the Australiasian Society to do DOXYPEP at the end of three days of the initial sexual intercourse. As compared to the USA, California protocol basically uses DOXYPEP after each sexual intercourse.

HOW TO USE DOXY-PEP?

USA, CALIFORNIA PROTOCOL: Take 2 pills of doxycycline at 100mg each tablet within 24 hours and no later than 72 hours after condomless oral, anal or vaginal sex. If you are having sex daily for 30 days then you will be using DOXYPEP daily amounting to a total of 60 pills used in 30 days.

Interpretation:

If a person is sexually active everyday then they will be using 2 tablets of DOXYPEP which translates into 60 tablets for 30days and 720 tablets for 1 year. The amount of DOXYCYCLINE consumed will be staggering high. Even people who are suffering with acne usually uses DOXYCYCLINE for about 3 months only, whereas DOXYPEP according to the USA, CALIFORNIA protocol can be used infinitely as long as the person is sexual active. My preference is not to use DOXYPEP at such a frequent dosing, rather I perfer and support the Australiasian Society protocol

AUSTRALIASIAN SOCIETY PROTOCOL: This protocol is just a consensus between experts in the infectious disease field. In this protocol we are limiting the use of Doxy PEP once every 72 hours. This means, if you have sex every day for 30days you will be limiting the dosage to only 10 times per month, thus limiting the usage and resistance.

WHAT IS THE AUSTRALIASIAN SOCIETY PROTOCOL FOR DOXY PEP?

Doxy-PEP involves taking 200mg of doxycycline up to 72 hours after a sexual act to reduce the risk of bacterial sexually transmitted infections (STI). Among gay, bisexual, and other men who have sex with men (GBMSM), clinical trials of Doxy-PEP have shown significant reductions in syphilis (by 70–80%) and chlamydia (by 70–90%), and to a lesser degree, gonorrhoea (ineffective in some trials, or 50–55% reduction in other trials, due to varying levels of tetracycline resistance in gonococcal isolates in different populations).

However, uncertainty remains regarding unintended outcomes from Doxy-PEP. These may include harms to individuals taking Doxy-PEP, such as disruptions to their microbiome and increased antimicrobial resistance (AMR) in STIs and other organisms, and harms to the community through increased population-level AMR. As such, individuals who might benefit from Doxy-PEP need to be supported to weigh up the potential benefits versus the potential harms from using Doxy-PEP, while considering whether this STI prevention strategy is suitable for them in their current context, in addition to conventional STI prevention strategies such as condoms.

Evidence for the effectiveness of Doxy-PEP, and considerations around potential risks of Doxy-PEP, are described in detail in ASHM’s previously published interim position statement.

On 17 March 2023, ASHM convened a national roundtable discussion on the use of Doxy-PEP in Australia, as listed in the appendix. The stakeholders included community representatives, clinicians, researchers, and experts in infectious diseases, public health, epidemiology, microbiology, and antimicrobial stewardship, to review data, exchange expertise, and develop guidance. ASHM has developed this consensus statement in consultation with the stakeholders present at the roundtable. There was broad consensus in the group on the recommendations listed below, with the notable exception that a minority of stakeholders expressed that Doxy-PEP should be considered only to prevent syphilis among GBMSM, rather than primarily be considered for this purpose. Additionally, some stakeholders expressed concern that the impact of Doxy-PEP on gonococcal AMR, and AMR in other organisms, has not yet been assessed sufficiently.

While Doxy-PEP is an effective strategy to prevent bacterial STIs such as chlamydia, gonorrhoea and syphilis among GBMSM, the risk/benefit calculation is most favourable for the prevention of syphilis. Of the bacterial STIs, syphilis carries the greatest morbidity among GBMSM, especially among GBMSM living with HIV. In contrast, the majority of chlamydia and gonorrhoea infections among GBMSM are asymptomatic, and they rarely cause complications. In addition, Doxy-PEP is less likely to be effective to prevent gonorrhoea in the Australian context, due to high rates of tetracycline resistance in Australian gonococcal isolates. Given these considerations, Doxy-PEP should be considered primarily to prevent syphilis among GBMSM. Importantly, for these same reasons, a minority of stakeholders held the view that Doxy-PEP should be considered only for the prevention of syphilis among GBMSM (as opposed to “primarily”).

Known risk factors for STIs include sexual behavioural history (e.g., sex without condoms, casual sexual partners, sexualised drug use), current use of HIV PrEP, and HIV-positive status. A recent analysis of clinic data from Boston (USA) explored the efficiency of different Doxy-PEP prescribing strategies by comparing the number needed to treat (NNT) using Doxy-PEP to prevent a bacterial STI case. This study found that prescribing Doxy-PEP for 12 months to individuals with one or more recent STI diagnoses (within the previous 12 months) was an efficient strategy for reducing the amount of Doxy-PEP prescribed, with NNTs ranging from 1.3–1.5 to prevent one bacterial STI case over 12 months. As discussed above, the prevention of syphilis deserves particular attention, and the same analysis found that prescribing Doxy-PEP to individuals currently diagnosed with syphilis resulted in the most efficient strategy for preventing subsequent syphilis diagnoses (NNT=9.5 if Doxy-PEP is used for 12 months)

STIs have different implications for GBMSM with cisgender female sexual partners or other sexual partners with a uterus, due to risk of transmission to these partners. In women and other people with a uterus, chlamydia and gonorrhoea can cause pelvic inflammatory disease and associated complications (e.g., infertility and ectopic pregnancy). Maternal syphilis can result in several complications, including miscarriage, stillbirth, neonatal death and congenital syphilis. Because of these additional risks, a lower threshold may be warranted for prescribing Doxy-PEP to GBMSM with cisgender female sexual partners or other sexual partners with a uterus. However, it should be noted that Doxy-PEP has not been studied in terms of prevention benefit for sexual partners.

These recommendations are intended for GBMSM and do not apply to other communities or populations. Importantly, Doxy-PEP was found to be ineffective in a study of cisgender women in Kenya, although further analysis has suggested that this was the result of low adherence to Doxy-PEP. Guidance for other communities or populations will need to be developed as evidence emerges.

WHAT ARE THE RECOMMENDATIONS IN THE AUSTRALIASIAN SOCIETY PROTOCOL FOR DOXY PEP?

1. Doxy-PEP should be considered primarily for the prevention of syphilis in GBMSM who are at risk of this STI, although for some individuals the reduction in chlamydia, and the lesser reduction of gonorrhoea might be important. Some stakeholders held the view that Doxy-PEP should be considered only for the prevention of syphilis in GBMSM, for the reasons listed above.

   
   

2. While evidence for appropriate suitability criteria for commencing Doxy-PEP is limited, the following might be appropriate for considering doxy-PEP until further data emerges:

   • GBMSM with a recent syphilis diagnosis (e.g., within the previous six or twelve months); or

   • GBMSM with two or more recent other (i.e., not syphilis) bacterial STI diagnoses (e.g., within the previous six or twelve months); or

   • GBMSM who identify an upcoming period of heightened STI risk, for example, attendance at a sex event, or holiday plans that likely involve sexual activity with multiple casual sexual partners; or

   • GBMSM with concurrent male and cisgender female sexual partners or other sexual partners with a uterus, recognising the additional health risks posed by chlamydia, gonorrhoea and syphilis for people with a uterus.

   • GBMSM who present for HIV PEP can also consider Doxy-PEP, although the indications for HIV PEP do not necessarily indicate a need for Doxy-PEP.

     
     

3. Given that STI risk is often not static, it is recommended to use Doxy-PEP for a pre-defined period, e.g., 3–6 months, followed by review of the need for ongoing use.

   
   

4. Doxy-PEP users should be assisted to maximise the benefits of Doxy-PEP while minimising overall antibiotic use. For example, if a Doxy-PEP user tends to have multiple sexual partners during weekends but few during the week, then a single Monday morning dose of 200mg Doxy-PEP should adequately cover their STI risk, rather than multiple doses over the weekend.

   
   

5. In general, it is not recommended to use daily doxycycline as pre-exposure prophylaxis (Doxy-PrEP, 100mg daily), as this often results in greater antibiotic consumption than Doxy-PEP, and fewer data support the use of Doxy-PrEP. However, for some people, Doxy-PrEP might be appropriate during periods of heightened (daily) sexual activity that places them at risk of STIs.

   
   

6. Other antibiotics (e.g., azithromycin) should not be used instead of doxycycline for STI prevention.

   
   

7. STI screening: Doxy-PEP users should continue to undergo STI screening in line with STI testing guidelines for GBMSM, as the ideal STI screening interval for people using Doxy-PEP has not yet been determined. Current guidelines recommend three-monthly screening for chlamydia, gonorrhoea, and syphilis for this population, but this recommendation might change. Additionally, Doxy-PEP users should be encouraged to attend for STI testing whenever they have symptoms.

   
   

8. Culture samples must be collected for all gonorrhoea diagnoses prior to administration of antibiotics, to enable AMR surveillance for this organism.

   
   

9. It is recommended to discuss personal and population-level AMR risks with Doxy-PEP users. Resources should be made available to assist clinicians to raise AMR issues during these conversations in a manner that is appropriate and sensitive to the patient’s needs.

   
   

10. HIV risk must be assessed and addressed during Doxy-PEP use. GBMSM who are HIV-negative must be supported to access effective HIV-prevention strategies such as HIV PrEP, and GBMSM living with HIV who are not accessing HIV care must be supported to do so.

WHAT CAN DOXY PEP BE USED FOR？

1.       Doxycycline is a special group of antibiotics which can be used for other purposes besides treatment for sexually transmitted diseases as first line against Chlamydia, Ureaplasma and mycoplasma. It is very effective against bacteria without a cell wall namely ureaplasma and mycoplasma.

2.       Doxycycline can be used to treat syphilis but it is not the best option because syphilis can penetrate into your brain and stay in your brain. Doxycycline is unable to reach into the brain as it is blocked by the blood brain barrier. It is similar when you are in Johor Bahru and you are entering Singapore without a passport. Doxycycline does not have that "passport" to cross from the blood stream to the brain. Therefore Doxycycline probably more effective in the initial part of syphilis namely Primary Syphilis as it is possible that the pathogen may not have crossed into the brain yet, making Doxycycline still effective. If the pathogen has crossed over to the brain then you will need Penicillin or Ceftriaxone group as these groups have the "Passport" to cross the blood brain barrier. It is important for clinicians to note this important point as I had a few expensive and posh clinics whose management are dubious and they do not understand the fundamentals of treatment.

3.       Doxycycline can be used for acne treatment against the common Propionibacteria which tends to cause acne. I usually will decide if it is necessary to start on Doxycycline after I have reviewed the face with a dermascope and woodlamp. Woodlamp will help to show if the acne is caused by Propionibacteria and only then we will commence Doxycycline. Most clinicians just empirically start their clients on Doxycycline despite the causative agent of the acne is unrelated to Propionibacteria, this causes delayed in effective management and treatment causing low-self esteem in their clients. We do things systematically and everything we do has a reasoning behind it.

4.       Finally, Doxycycline at very low doses can evoke an anti-inflammatory effect which can be used to replace steroids.

WHY IS DOXYCYCLINE IS NOT THE BEST OPTION FOR SYPHILIS TREATMENT?

Doxycycline can be used to treat syphilis but it is not the best option because syphilis can penetrate into your brain and stay in your brain. Doxycycline is unable to reach into the brain as it is blocked by the blood brain barrier. It is similar when you are in Johor Bahru and you are entering Singapore without a passport. Doxycycline does not have that "passport" to cross from the blood stream to the brain. Therefore Doxycycline probably more effective in the initial part of syphilis namely Primary Syphilis as it is possible that the pathogen may not have crossed into the brain yet, making Doxycycline still effective. If the pathogen has crossed over to the brain then you will need Penicillin or Ceftriaxone group as these groups have the "Passport" to cross the blood brain barrier. It is important for clinicians to note this important point as I had a few expensive and posh clinics whose management are dubious and they do not understand the fundamentals of treatment.

WHAT IS THE EFFECTIVE PERCENTAGE OF DOXYCYCLINE FOR SOME PATHOGENS?

In the metadata, the proportions of tetracycline, doxycycline, and minocycline resistance in Mycoplasma and Ureaplasma urogenital isolates were reported 14.2% (95% CI 8.2–23.2%), 5% (95% CI 3–8.1%), and 11.9% (95% CI 6.3–21.5%), respectively. This indicates that the effectiveness of Doxycycline is much lower when use to treat Ureaplasma and Mycoplasma. Proper testing is very important so that we do not miss these infections and end up using Doxycycline continuously with the assumption that it is still highly effective in dealing with Ureaplasma and Mycoplasma.

WHAT ARE THE SIDE EFFECTS OF DOXY-PEP?

DOXY-PEP is not without side effects and side effect can range from minor to major.

1. Using this medicine while you are pregnant can harm your unborn baby. Use an effective form of birth control to keep from getting pregnant. If you think you have become pregnant while using this medicine, tell your doctor right away.

2. This medicine may darken the color of your skin, nails, eyes, teeth, gums, or scars. Talk with your doctor if you have any concerns.

3. Doxycycline may cause diarrhea, and in some cases it can be severe. It may occur 2 months or more after you Stop taking doxycycline. Do not take any medicine to treat diarrhea without first checking with your doctor. Diarrhea medicines may make the diarrhea worse or make it last longer. If you have any questions about this or if mild diarrhea continues or gets worse, check with your doctor.

4. Birth control pills (containing estrogen) may not work properly while you are using doxycycline.

5. Serious skin reactions, including exfoliative dermatitis, erythema multiforme, Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis, drug reaction with eosinophilia and systemic symptoms (DRESS) can occur with this medicine.

6. Increased pressure inside the head (intracranial hypertension)

7. Itching of the vagina or genital area

8. Pain during sexual intercourse

9. Thick, white vaginal discharge with no odor or with a mild odor

10. Doxycycline may cause your skin to be more sensitive to sunlight than it is normally. Exposure to sunlight, even for short periods of time, may cause skin rash, itching, redness or other discoloration of the skin, or a severe sunburn. When you begin taking this medicine:

    • Stay out of direct sunlight, especially between the hours of 10:00 a.m. and 3:00 p.m., if possible.

    • Wear protective clothing, including a hat. Also, wear sunglasses.

    • Apply a sunblock product that has a sun protection factor (SPF) number of at least 15. Some patients may require a product with a higher SPF number, especially if they have a fair complexion. If you have any questions about this, check with your doctor.

    • Apply a sunblock lipstick that has an SPF of at least 15 to protect your lips.

    • Do not use a sun lamp or tanning bed or booth.