The correct dosage of Metamucil depends on a person's age and medical condition, and a person should not increase the amount or frequency of each dose unless directed, advises WebMD. Those who overdose on Metamucil should get emergency medical attention. Allergic reactions include vomiting, rectal bleeding or skin rash.
Metamucil is an oral medication used to treat constipation. Metamucil may affect the absorption of other medications a person takes and should be taken at least two hours before or after other medications, states WebMD. It should not be taken for more than seven days unless a doctor directs otherwise. If a dose is missed, a person should not take a double dose to catch up. It is important that a person takes Metamucil with sufficient liquid to avoid swelling of the product in the throat or esophagus, which may lead to choking, warns Drugs.com.