Can one cut a 24 hrs Allegra-D pill?
Allegra-D tablets have an extended-release mechanism, which releases the active ingredients slowly over time. It is available as either a 12-hour release tablet or 24-hour release tablet.
If you do cut or split the tablet, the extended-release mechanism will be destroyed, causing the entire dose to be delivered at once time. This greatly increases the risk of side effects.
If you are looking to adjust your dose of Allegra-D, you should consider getting each drug separately, as both fexofenadine and pseudoephedrine (the active ingredients in Allegra-D) are available as single drug products.
As mentioned in the overview section, splitting or cutting Allegra-D tablets will ruin the extended-release mechanism, causing the entire dose to be released at once. This is also-known-as 'dose-dumping'.
The decongestant in Allegra-D is pseudoephedrine. The 12-hour version of the product contains 120mg while the 24-hour contains 240mg.
Having 120mg, or worse yet, 240mg of pseudoephedrine given as a single-dose (which is what would occur if the tablets are split) would be considered an overdose of the drug.
Pseudoephedrine, when given in immediate-release formulations, is only recommended to be given at a maximum dose of 60mg every four to six hours.
Therefore, 120mg and 240mg of the drug, given in an immediate-release form, would constitute a two to four-fold overdose.
Pseudoephedrine is a potent vasoconstrictor, and taking too high a dose can (among other things):
Not only does splitting or cutting Allegra-D increase the risk of side effects (due to the large single dose of pseudoephedrine), it will no longer work for an extended period of time, negating the purpose of the product (which is to work for at least 12 to 24 hours).