Obimet is the brand name; the name of the medicine is metformin. The duration of action of normal preparation is shorter while SR (slow release) is longer. The normal release preparation can be taken either once or twice or thrice daily depending on the total daily dose required while SR is generally taken once daily. If a person is taking 500 mg normal release tablet twice daily, then the dose of SR product will be 1,000 mg once daily in the morning.