methacycline
noun
metha·cy·cline
| \ ˌmeth-ə-ˈsī-ˌklēn
\
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Medical Definition of methacycline
: a semisynthetic tetracycline C22H22N2O8 with longer duration of action than most other tetracyclines and used in the treatment of gonorrhea especially in penicillin-sensitive subjects