Along with the positive qualities of tablets as a dosage form, they have a number of disadvantages, namely: during storage tablets can lose their disintegration and cemented or, conversely, destroyed; with tablets in the body introduced auxiliary substances that sometimes cause side effects (for example, talcum powder irritates mucous membranes); some medecines form in the dissolution zone of highly concentrated solutions that can cause severe irritation of mucous membranes. This disadvantage is easily eliminated if such tablets before taking crushed and dissolved in a certain amount of water; tablets can not be introduced into the body when vomiting or fainting; not all patients, especially children, can freely swallow tablets.
Tablets are flat and biconvex round, oval disks or other shaped plates. The most common form is a flat cylindrical shape with a chamfer and a biconvex shape that is easy to swallow.
In addition, from the technological point of view, such forms of tablets are the most convenient for manufacturing and packaging, as they are easily and tightly packed, in addition, punches and dies for their manufacture are structurally simpler and economically more profitable.

Sometimes tablets may have a cylindrical shape.
The diameter of tablets varies from 3 to 25 mm, the most common tablets are from 4 to 12 mm. Tablets larger than 25 mm in diameter are called briquettes. The height of the tablets should be within 30 to 40% of their diameter.
Some tablets have inscriptions with the name of the medecine on the surface in the form of concave prints, as convex letters on the end of the tablets are more susceptible to abrasion and destruction. Tablets with a diameter of more than 9 mm have a risk (notch), which is applied to it during pressing with a punch. By notches tablets are easily broken and can be divided with sufficient accuracy into 2 or 4 doses to vary the dosage of the medecine substance.
The following classes of tablets are distinguished: Pressed tablets obtained by pressing medicinal powders on tablet machines. This method is the main method in the production of tablets.
Trituration tablets (molded, micro tablets) obtained by tabletting mass. This class of tablets is produced in cases where the use of pressure for any reason is undesirable (e.g., nitroglycerin tablets, when the use of pressure may cause an explosion), or the dosage of medecines is small, and the addition of a large number of excipients is inappropriate. The mass of such tablets may be up to 0.05 g.