NONE of the three cough syrups you have enquired about are effective for your condition.
You either have allergic rhinitis
or rhinosinusitis that can be established with skin prick tests or blood test
(specific IgE). If allergy results are negative, then your condition is non-allergic rhinitis.
You need (1) oral antihistamines like cetirizine
10mg or levocet 5mg plus (2) Flumast-AZ nasal spray
that is a combination of fluticasone
and azelastine 2 sprays/nostril twice daily. This should be taken for a minimum of 2 months (max 3 months) and then stopped to see if the effect lasts.
You can always restart if symptoms return.
Hope that was useful.