Syphilis treatment depends on what stage it is detected, but the first line treatment is benzathine benzylpenicillin given as a single dose deep IM injection single dose for syphilis when infected under 2 years, or two doses a week apart for infections longer than 2 years.20 
Alternative treatments for early syphilis are doxycycline or erythromycin for 14 days. For late, latent or asymptomatic infections of more than two years, doxycycline should be given for 28 days. Prophylactic doxycycline for 14 days should also be given to asymptomatic contacts of patients with infectious syphilis. 
Trichomoniasis, asymptomatic in half of people, is usually treated with metronidazole. The adult dose is 200mg three times a day for 7 days, or 400–500mg twice daily for 5–7 days, or 2g as a single dose. Alternatively, a single dose of tinidazole 2g may be prescribed for adults.22,23 
Non-specific PID may also respond to metronidazole 400mg twice daily for 14 days.22