Pseudoephedrine

Pseudoephedrine, sold under the brand name Sudafed among others, is a sympathomimetic medication which is used as a decongestant to treat nasal congestion. It has also been used off-label use for certain other indications, like treatment of hypotension. At higher doses, it may produce various additional effects including psychostimulant, appetite suppressant, and performance-enhancing effects. In relation to this, non-medical use of pseudoephedrine has been encountered. The medication is taken by mouth.

Side effects of pseudoephedrine include insomnia, elevated heart rate, increased blood pressure, restlessness, dizziness, anxiety, and dry mouth, among others. Rarely, pseudoephedrine has been associated with serious cardiovascular complications like heart attack and hemorrhagic stroke. Some people may be more sensitive to its cardiovascular effects. Pseudoephedrine acts as a norepinephrine releasing agent, thereby indirectly activating adrenergic receptors. As such, it is an indirectly acting sympathomimetic. Pseudoephedrine significantly crosses into the brain, but has some peripheral selectivity due to its hydrophilicity. Chemically, pseudoephedrine is a substituted amphetamine and is closely related to ephedrine, phenylpropanolamine, and amphetamine. It is the (1 S,2 S)-enantiomer of β-hydroxy- N-methylamphetamine.

Along with ephedrine, pseudoephedrine occurs natural product in ephedra, which has been used for thousands of years in traditional Chinese medicine. It was first chemical isolate from ephedra in 1889. Subsequent to its synthesis in the 1920s, pseudoephedrine was introduced for medical use as a decongestant. Pseudoephedrine is widely available over-the-counter (OTC) in both single-drug and combination drug dosage form. Availability of pseudoephedrine has been restricted starting in 2005 as it can be used to synthesize methamphetamine. Phenylephrine has replaced pseudoephedrine in many over-the-counter oral decongestant products. However, oral phenylephrine appears to be ineffective as a decongestant. In 2023, it was the 292nd most commonly prescribed medication in the United States, with more than 400,000 prescriptions. In 2023, the combination with brompheniramine and dextromethorphan was the 281st most commonly prescribed medication in the United States, with more than 700,000 prescriptions. In 2023, the combination with loratadine was the 300th most commonly prescribed medication in the United States, with more than 400,000 prescriptions.