The present invention aims to find a pharmaceutical preparation which treats or prevents glaucoma or ocular hypertension and is effective for patients with inadequate efficacies of glaucoma or ocular hypertension therapeutic agents. It has been found that omidenepag, an ester thereof, or a salt thereof has an excellent intraocular pressure lowering efficacy on patients with inadequate efficacies of other glaucoma or ocular hypertension therapeutic agents. Therefore, the omidenepag, the ester thereof, or the salt thereof of the present invention is useful as a pharmaceutical preparation which can treat or prevent glaucoma or ocular hypertension even in patients with inadequate efficacies of other glaucoma or ocular hypertension therapeutic agents.