As with all antibiotics, it is important to avoid missing doses. If you do miss a dose, simply take it as soon as you remember. If it is almost time for your next dose, skip the missed dose and continue with your regular schedule. Do not take a double dose.
Many different prescription metronidazole products are available in several different forms (see Metronidazole Prescription Drugs for more information). Many (but not all) are available in generic form.