What is the shelf life of an opened paracetamol (acetaminophen) syrup?

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Last updated: February 4, 2026View editorial policy

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Shelf Life of Opened Paracetamol Syrup

An opened paracetamol syrup remains stable and can be used for at least 6 months when stored properly at room temperature, based on stability testing showing no degradation of the active ingredient over this period. 1

Storage Stability and Duration

  • Paracetamol syrup formulations (2.5%, 125 mg/5 mL) maintain their full potency for at least 6 months after opening when stored at room temperature, with no changes in paracetamol content detected by spectrophotometric analysis (HPLC) throughout this period. 1

  • The syrup remains stable with no significant changes in organoleptic features (color, smell, transparency) during the 6-month monitoring period. 1

Important Storage Considerations and Pitfalls

  • Crystallization of paracetamol can occur on the lid, walls, and bottom of the bottle, particularly during winter months or in colder storage conditions. 1 This does not necessarily indicate loss of potency but may affect dosing accuracy if crystals are not redissolved.

  • Proper storage conditions include keeping the bottle tightly closed when not in use and storing at controlled room temperature to minimize crystallization risk. 1

  • pH-stabilized formulations with appropriate preservatives demonstrate superior long-term stability and are preferred for both pediatric and adult use. 1

Practical Recommendations

  • Opened paracetamol syrup can be safely used for up to 6 months, though manufacturers may recommend shorter periods (often 3 months) as a conservative measure to account for variable storage conditions in home settings. 1

  • If crystallization occurs, gently warm the bottle and shake well to redissolve crystals before measuring doses to ensure accurate dosing. 1

  • Discard the syrup if there are obvious changes in color, odor, or if contamination is suspected (such as visible particles or cloudiness not related to crystallization). 1

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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