How Long Does Robitussin Stay in Your System

Robitussin DM

Robitussin DM is an over-the-counter cough medicine with the active ingredients guaifenesin and dextromethorphan. The former is an expectorant while the latter is a mild narcotic with antitussive properties.

How long does Robitussin DM stay in your system

The half-life of Robitussin in people with normal metabolic rates has been observed to be around 2-4 hours; somebody with a poor metabolic rate could take up to 3-6 hours to excrete half of the Robitussin they have taken.

Thus we can conclude that individuals with a normal metabolic rate are expected to eliminate the dextromethorphan within Robitussin 11-22 hours after they take it for the last time, while a person with a poor metabolic rate is going to take 16½-33 hours to excrete the same amount of ingested dextromethorphan.

Guaifenesin, on the other hand, has an elimination half-life of 1-5 hours, meaning it would take around 5½-27½ hours for the body to completely get rid of guaifenesin.

In any case, Robitussin will be completely eliminated from your body after a maximum duration of 33 hours after your last dose.

Robitussin AC

Robitussin AC is another form of Robitussin with codeine as the active ingredient with guaifenesin as the other component. This formulation is available only with a prescription.

How long does Robitussin AC stay in your system

The codeine component of Robitussin AC has an elimination half-life of around 2 hours 54 minutes. As a result, it can stay in your system for up to 17 hours before getting excreted.