Hi.. Welcome to HEALTHCARE MAGIC.. I have gone through your query and can understand your concern.. As per your complain Dexamol contains Acetaminophen as the active ingredient and in case if it is expired you should not take it a at all as it may not only loose effectiveness but can decompose and the molecules can break into harmful/toxic decomposition products and can be fatal upon intake.. I would suggest you that in case if you have post nasal drip and sore throat that can be due to causes like Sinusitis, upper respiratory tract infection etc you ned to consult an Otolaryngologist and get evaluated and he can do a clinical examination and also advise investigations like Throat swab culture, blood investigation and x ray of sinuses if sinus infection is suspected to rule out the exact cause of problem and treat accordingly.. You can be advised antibiotics, anti-inflammatory painkiller, decongestants, anti allergics, warm saline gargles, steam inhalations and use a humidifier in your room.. Avoid spicy and chilled foods and take a soft bland diet.. Sip on warm water throughout the day.. Hope this information helps.. Thanks and regards. Dr.Honey Nandwani Arora.