Antihistamines, Decongestants, Antitussives, and Expectorants Drugs

Block histamine receptors (H1) on the surfaces of basophils and mast cells preventing the release of histamine

• Nasal allergies, allergic rhinitis, common cold
• Allergic reactions, motion sickness, Parkinson’s disease, vertigo
• Sleeping aid

• Drug allergy, narrow-angle glaucoma, cardiac disease, kidney disease, hypertension, bronchial asthma, COPD, peptic ulcer disease, seizure disorders, benign prostatic hyperplasia, pregnancy
• Impaired liver function or renal insufficiency, lactating mothers

• Shrink engorged nasal mucous membranes and relieve nasal stuffiness
• Constrict the small arterioles that supply the upper respiratory tract

Aimed at the inflammatory response elicited by invading organisms

Acute or chronic rhinitis, common cold, sinusitis, hay fever or other allergies

Drug allergy, narrow-angle glaucoma, uncontrolled cardiovascular disease, hypertension, diabetes, hyperthyroidism, and prostatitis

• Nervousness, insomnia, palpitations, tremor
• Hypertension, headache, dizziness

suppress reflex through direct action on the cough center of the CNS

suppresses by anesthetizing stretch receptor cells in tract preventing reflex stimulation

Primarily to stop cough reflex when cough is nonproductive and/or harmful

Opioid dependence and risk for respiratory depression

Dizziness, headache, sedation, nausea, and others

Dizziness, drowsiness, nausea

Sedation, nausea, vomiting, lightheadedness, constipation

Reflex stimulation or direct stimulation of the secretory glands in the respiratory tract

Common cold, bronchitis, laryngitis, pharyngitis, pertussis, influenza, measles

Nausea, vomiting, and gastric irritation