As is always the case, do not adjust your dosage unless your healthcare provider specifically instructs you to do so. For clindamycin capsules, the usual dosage for adults ranges from 150 mg to 450 mg every six hours, depending on the particular infection.For the injectable form, typical doses range from 1200 mg up to 2700 mg total per day, divided into two to four smaller doses per day.s is always the case, do not adjust your dosage unless your healthcare provider specifically instructs you to do so. For clindamycin capsules, the usual dosage for adults ranges from 150 mg to 450 mg every six hours, depending on the particular infection.