When vomiting or severe disease precludes oral administration or when the central nervous system is affected, parenteral ceftriaxone 2 g once a day or 1 g every 12 hours for 10 to 14 days, doxycycline 1 to 2 mg / kg IV every 12 to 24 hours, or penicillin G 3 million units IV every 4 hours may be given to adults or children > 8 years of age.