Benzathine Penicillin G
Treatment for Syphilis
Typical Dosage: 2.4 million units IM (single dose); 2.4 million units IM weekly for 3 weeks
Effectiveness
98%
Safety Score
70%
Clinical Trials
24
Participants
1M
Comparative Safety Scale(Higher is safer)
Cyanide☠️
Meth💀
Cigarettes🚬
Chemo☢️
Alcohol🍺
Morphine💊
Antibiotics💉
Tylenol💊
Exercise🏃
Water💧
70
DangerousModerateSafe
Treatment Details
Dosage Range
2.4 million units IM (single dose); 2.4 million units IM weekly for 3 weeks
Time to Effect
1-2 weeks for serologic response
Treatment Duration
Single dose or 3 weekly doses
Evidence Quality
HIGHNumber Needed to Treat (NNT)
1(Treat 1 patients to see 1 additional successful outcome)
Number Needed to Harm (NNH)
10(Treat 10 patients to see 1 additional serious adverse event)
Confidence Score
98%confidence in effectiveness data
Health Economics
Annual Cost of Care
Drug Cost:$100
Monitoring:$200
Side Effect Mgmt:$75
Total Annual:$375
Cost-Effectiveness Analysis
Cost-Effectiveness Rating
EXCELLENTICER
$10,000/QALY
QALYs Gained
2.5
Outcome-Based Costs
Cost per Responder
$395
Cost per Remission
$395
Prescription Access Economics
Physician Visit Cost
$300/year
Time Cost
$60/year
Travel + wait time
Insurance Admin Cost
$40/year
Prior auth, claims
Rx Price
$100/year
Risk Assessment
Misuse Risk
MODERATEMissed Diagnosis Risk
HIGHRequires Monitoring
YesNeeds lab work/checkups
Benzathine Penicillin G Outcomes
for Syphilis
Efficacy Outcomes
Overall Effectiveness
+98%
Response Rate
+95%
Remission Rate
+95%
Common Side Effects
Pain at injection site
+99%
Jarisch-Herxheimer reaction
+20%
Hypersensitivity/Allergic reaction (mild)
+8%
Hypersensitivity/Allergic reaction (severe/anaphylaxis)
+1%
Active Clinical Trials
9 active trials recruiting for Benzathine Penicillin G in Syphilis
Oral Amoxicillin Compared to Penicillin G Benzathine for the Treatment of Acquired Syphilis.
NCT06877351ACTIVE NOT RECRUITINGPHASE3
120 participants
INTERVENTIONAL
Buenos Aires City, Argentina
Started: Aug 14, 2024
Study of Ceftriaxone and Benzathine Penicillin G During Pregnancy
NCT07207876RECRUITING
110 participants
OBSERVATIONAL
Los Angeles, United States +8 more
Started: Feb 16, 2026
Cefixime Clinical Trial
NCT04958122RECRUITINGPHASE3
400 participants
INTERVENTIONAL
Los Angeles, United States
Started: Jun 20, 2021
Congenital Syphilis Treatment Trial (CONSISTENT) in Neonates
NCT07457385NOT YET RECRUITINGPHASE4
374 participants
INTERVENTIONAL
Birmingham, United States +10 more
Started: Nov 1, 2026
Comprehensive Ambulatory Antibiotics for the Treatment of Congenital Syphilis
NCT06921213RECRUITINGPHASE2
90 participants
INTERVENTIONAL
Jakarta, Indonesia +2 more
Started: May 4, 2026
Comparisons of Treatment Responses of Early Syphilis to Benzathine Penicillin G With or Without Doxycycline
NCT06069141RECRUITINGNA
688 participants
INTERVENTIONAL
Hsinchu, Taiwan +8 more
Started: Jan 1, 2024
Linezolid for Syphilis Pilot Study
NCT05548426ACTIVE NOT RECRUITINGPHASE2
24 participants
INTERVENTIONAL
Chicago, United States +4 more
Started: Sep 28, 2023
Evaluation of Antimicrobial Prophylaxis to Prevent Syphilis in Pregnancy in Patients at Risk in Rio de Janeiro, Brazil
NCT07189208RECRUITINGPHASE2
500 participants
INTERVENTIONAL
Duque de Caxias, Brazil +3 more
Started: Sep 24, 2025
LIMIT Trial - Lidocaine With Intramuscular Injection of Benzathine Penicillin G for Treponema Pallidum Treatment
NCT06391125RECRUITINGPHASE3
48 participants
INTERVENTIONAL
St Louis, United States
Started: Jul 1, 2024
Completed Clinical Trials
5 completed trials for Benzathine Penicillin G in Syphilis
Phase 4 Comparative Trial of Benzathine Penicillin G for Treatment of Early Syphilis in Subjects With or Without HIV Infection
NCT03637660COMPLETEDPHASE4
249 participants
INTERVENTIONAL
Birmingham, United States +9 more
Started: Oct 31, 2018
Azithromycin/Bicillin Syphilis
NCT00031499COMPLETEDPHASE3
593 participants
INTERVENTIONAL
Birmingham, United States +9 more
Started: Jun 1, 2000
Syphilis Response to Higher Penicillin Dosage: The 2.4 Versus 7.2 Study
NCT02611765COMPLETEDPHASE4
64 participants
INTERVENTIONAL
Started: Sep 1, 2008
Cefixime for Alternative Syphilis Treatment
NCT03660488COMPLETEDPHASE2
58 participants
INTERVENTIONAL
Beverly Hills, United States +9 more
Started: Sep 3, 2018
Alternative Antibiotics for Syphilis
NCT05069974COMPLETEDPHASE3
165 participants
INTERVENTIONAL
Barcelona, Spain +10 more
Started: Oct 14, 2021
Showing 20 of 26 total trials