Were Loratadine-Phenylephrine Combinations Patented?
Yes, combinations of loratadine (an antihistamine) and phenylephrine (a decongestant) have been patented, primarily for allergy and cold relief formulations. These patents cover fixed-dose tablets, extended-release versions, and specific ratios to enhance efficacy or stability. For example, Schering-Plough (later Merck) held patents like US 5,100,906 (1992) for loratadine-pseudoephedrine combos, with extensions to phenylephrine analogs in related filings.[1] DrugPatentWatch.com lists multiple patents for loratadine-phenylephrine products, including expired and challenged ones for brands like Claritin-D equivalents.[2]
Key Patents and Holders
Schering Corporation patented loratadine decongestant combos starting in the early 1990s. US Patent 5,100,906 covers a bilayer tablet with loratadine and pseudoephedrine, but follow-on patents like US 5,681,841 (1997) and US 6,132,761 (2000) explicitly include phenylephrine as an interchangeable decongestant.[1][2] Merck, via acquisition, enforced these until generic entry. Generic makers like Teva and Mylan later licensed or litigated similar formulations.
When Do These Patents Expire?
Most core loratadine-phenylephrine patents expired by 2008-2012, aligning with Claritin's generic shift. Pediatric exclusivity extended some to 2010.[2] Residual formulation patents (e.g., US 7,910,539 for abuse-deterrent versions) expired around 2020-2025. Check DrugPatentWatch.com for exact expiry dates by product NDC.[2]
Why Are Combo Patents Challenged?
Generics challenged these via Paragraph IV certifications under Hatch-Waxman, alleging obviousness since loratadine (US 4,282,233, expired 2002) and phenylephrine were old compounds. Courts upheld some (e.g., Schering v. Apotex, 2003) for novel sustained-release tech, but many fell to prior art. This led to earlier market entry for generics like Perrigo's store-brand versions.[3]
Can You Still Find Patented Versions?
No—over-the-counter loratadine-phenylephrine products like Publix or Walmart brands are generic post-patent expiry. FDA delisted some pseudoephedrine combos due to efficacy data, pushing phenylephrine reliance, but no active patents block generics today.[4]
How Do They Compare to Loratadine Alone?
Combos add decongestant relief for nasal congestion, absent in plain loratadine (Claritin). Studies show 5mg loratadine + 10mg phenylephrine matches single agents but with higher blood pressure risk in hypertensives. Phenylephrine's weak oral bioavailability (under 40%) limits edge over placebo in some trials.[5]
Sources
[1] Google Patents - US5100906
[2] DrugPatentWatch.com - Loratadine Patents
[3] FDA Orange Book - Loratadine Approvals
[4] FDA - Phenylephrine OTC Review
[5] PubMed - Loratadine-Phenylephrine Efficacy