A pharmacist sometimes may need to substitute one formulation of a drug for another. This may be required by availability, cost containment, patient convenience or other factors. This can be done safely provided certain guidelines are observed.

NOTE: These guidelines reflect Texas state law and may vary in other jurisdictions. These guidelines do not cover substitution of a generically equivalent product.


Examples: capsules instead of tablets; tablets instead of liquid


Guidelines for changing a prescribed drug's form at the time of dispensing:

(1) The patient consents to the change.

(2) The physician is notified of the change and agrees to the substitution.

(3) The formulation dispensed contains the identical amount of active ingredient as the form originally prescribed.

(4) The formulation is not enteric-coated or time-released.

(5) The formulation does not alter clinical outcome for the condition being treated.



• The contraindication for enteric-coated or time-released forms may reflect the difficulty in achieving an equivalent time course using alternative formulations. I would imagine that substituting a time-released tablet for a time-released capsule with similar release characteristics would be appropriate. As noted by B. Alpert in Barron's Technology Week (March 4, 2002): " But controlled-release capsules and tablets are among the hardest drugs to make, needing layers of tricky ingredients to ensure that medicine trickles out at predicted levels."

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