Page 4. Beta decay is a radioactive process in which an electron is emitted from the nucleus of a radioactive atom, along with an unusual particle called an antineutrino.The neutrino is an almost massless particle that carries away some of the energy from the decay process.age 4. Beta decay is a radioactive process in which an electron is emitted from the nucleus of a radioactive atom, along with an unusual particle called an antineutrino.
There is also a 12-hour extended-release form of pseudoephedrine; it should also start working within half an hour of taking your first dose, but will last much longer. Because it can last up to 12 hours, remember that you should not take more than two tablets in a 24-hour period.
Before taking fexofenadine and pseudoephedrine, 1  tell your doctor and pharmacist if you are allergic to fexofenadine (Allegra), pseudoephedrine (Sudafed, in Dimetapp, in Drixoral, others), any other medications, or any of the ingredients in the tablets.2  Ask your pharmacist for a list of the ingredients.f you are taking fexofenadine and pseudoephedrine 12-hour tablets, you may notice something that looks like a tablet in your stool. This is just the empty tablet shell, and this does not mean that you did not get your complete dose of medication.