Monticope-A is primarily for allergies and congestion, but thick yellow mucus does not automatically mean you need an antibiotic. Most nasal blockages start as viral infections, which antibiotics cannot cure. Self-prescribing antibiotics can lead to harmful side effects and bacterial resistance.\n\nIf your symptoms have lasted over 10 days, worsened after initially improving, or are accompanied by a high fever and severe facial pain, it could be a bacterial sinus infection. You should consult a doctor for a proper physical examination. If appropriate, they may prescribe an antibiotic like Amoxicillin-Clavulanate. For immediate relief, try saline nasal sprays, steam inhalation, and staying well-hydrated.