CD on a prescription means controlled delivery.
On some drugs the CD may also mean controlled drugs but for most other medications, the CD means controlled delivery.
TR on a prescription means time release and LA on a prescription means long acting.
A controlled delivery medication is a medication that releases the correct dose of the drug directly into the desired zone and during the required period of time which allows for maximizing the efficacy of the therapeutic and minimizing any possible side effects.
ER on a prescription means that the prescription medication is extended release.
Extended release medications are designed to last longer in the body.
As a result of the extended release the medication last longer and allows you to take the medication less often when compared to the IR version of the medication.
With an ER or Extended Release medication you may only need to take 1 to 2 doses of the medication a day when compared to the possible 3 to 4 doses of the medication in IR version.
IR on a prescription means immediate release which means that the medication is immediately released in your body and does not stay as long in the body so you may need to take more of the medication when compared to extended release medication.
The standard dosage form of most oral medication is the IR or immediate release version.
So if your medication says IR it means it's immediate release and if your medication says ER or XR it means that the medication is a longer acting extended release medication.
Immediate release medications are not as long acting as extended release medications are.