17,20-dimethyl Prostaglandin F1a (17,20-dimethyl PGF1a) is an analog of the limaprost family with structural modifications intended to give it a prolonged half-life and greater potency. Limaprost is an analog of PGE1 which is orally active in both rats and guinea pigs.{6808} The additional methyl groups in the lower side chain confer a 10-1,000 fold increase in potency over the parent compound.{6808} 17,20-dimethyl PGF1a has lower side chain modifications identical to limaprost. There are no published reports describing the pharmacology of 17,20-dimethyl PGF1a.