Caution Advised for Users of Pseudoephedrine: What You Need to Know!

SINGAPORE – Medical experts have weighed in on the use of medications containing decongestant pseudoephedrine, advising that individuals do not need to avoid these drugs unless they have serious health concerns such as uncontrolled hypertension or kidney failure, which significantly raise the risk of adverse effects.

Despite the reassurance, healthcare professionals emphasize the importance of following prescribed dosages meticulously. Anyone experiencing unusual symptoms, such as nausea or visual disturbances, should seek immediate medical assistance.

The recent decision by pharmaceutical giant GSK to cease production of Zyrtec-D—a widely used antihistamine and decongestant containing pseudoephedrine—has raised alarm among readers of The Straits Times. Pseudoephedrine is found in a range of medications available in Singapore, including Clarityn-D, Telfast-D, and Sudafed.

While the incidence of severe side effects associated with pseudoephedrine is rare, the drug has been linked to serious conditions like posterior reversible encephalopathy syndrome (PRES) and reversible cerebral vasoconstriction syndrome (RCVS). PRES can lead to symptoms such as seizures, headaches, and visual impairments, and it has the potential to affect cognitive functions. Fortunately, early diagnosis often results in effective treatment.

RCVS exhibits stroke-like symptoms due to the sudden spasm and constriction of blood vessels, putting nearly one-third of those affected at risk for long-term disabilities like muscle weakness.

Dr. John Cheng, chief medical officer of Healthway Medical Group, underscores the rarity of these severe reactions, clarifying that they are often the result of multiple contributing factors, including pre-existing health issues, excessive doses, or the combined effects of other medications that influence the central nervous system or blood pressure. He adds that individuals with factors that heighten risk—such as hypertension, migraines, or a history of strokes—should exercise additional caution.

For anyone prescribed pseudoephedrine, it is crucial to stick to dosing instructions and consult healthcare providers before initiating the medication. Any unusual symptoms—such as severe headaches, visual changes, or confusion—mandate immediate medical attention.

In April 2024, Singapore's Health Sciences Authority issued a safety alert indicating plans to collaborate with drug manufacturers to enhance warnings regarding PRES and RCVS on product labeling for medications containing pseudoephedrine. The regulatory body also suggests that healthcare practitioners counsel patients on symptoms warranting urgent medical review, which include sudden, severe headaches, nausea, vomiting, visual changes, seizures, and altered mental status.

The UK's National Health Service (NHS) warns that individuals with heart conditions should be particularly cautious with pseudoephedrine due to its potential to narrow blood vessels throughout the body, which can elevate blood pressure and heart rate. Other groups advised to avoid or limit use of the drug include those with glaucoma, enlarged prostates, and liver or kidney issues. The NHS also cautions against prolonged use—lasting more than seven days—due to an increased risk of side effects.

As debates continue around the safety of drugs like pseudoephedrine, staying informed and consulting healthcare professionals remains essential for safe usage.