Related Experiment Video
Updated: Aug 14, 2026

Diagonal Method to Measure Synergy Among Any Number of Drugs
Published on: June 21, 2018
Controlled comparison of anew antihistamine-decongestant combination to its individual components
Abstract:
A new antihistamine-decongestant combination tablet, containing azatadine maleate and pseudoephedrine sulfate, was compared to its individual ingredients and also to placebo, in a double-blind, randomized parallel-group clinical study. Two patient groups were treated, one with seasonal allergic rhinitis for two days during the peak of the ragweed season, and another with perennial allergic rhinitis for an extended six-week period. In both groups the combination was found better than its single components, and all three treatments better than placebo, in relieving the symptoms of allergic rhinitis. A few patients reported a transient drowsiness attributable to azatadine.
Related Concept Videos
Adrenergic Agonists: Direct-Acting Agents
These agents can be classified...
Adrenergic Agonists: Mixed-Action Agents
Ephedrine and pseudoephedrine lack a catecholamine group, making them less susceptible to degradation by metabolic enzymes. They have increased oral bioavailability and lipophilicity, resulting in a longer duration of action. Their response is reduced by...
Upper Respiratory Drugs: Decongestants
Most decongestants are readily available over-the-counter in various...
Upper Respiratory Drugs: First and Second-Generation Antihistamines
Histamine binds to specific receptor sites, known as H1 receptors, on tissue cells, triggering inflammation and swelling. Antihistamines combat these effects by competing with histamine for these receptor sites. By...
Upper Respiratory Drugs: Antitussives, Expectorants, and Mucolytics
Antitussives include codeine, dextromethorphan (Robitussin), and benzonatate (Tessalon). Codeine and dextromethorphan exert their effects centrally by suppressing the cough reflex center in the medulla. Benzonatate operates peripherally within the respiratory tract by anesthetizing...
Antiasthma Drugs: Muscarinic Receptor Antagonists
Antimuscarinic agents compete with ACh for the same binding site on the muscarinic receptors. By binding to these receptors, they inhibit the downstream effects of ACh and block the parasympathetic...

