This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pharmacology
Which of the following term best describes the antagonism of bronchoconstrictor eﬀect (mediated at the leukotriene receptors)of  leukotrienes by terbutaline  (acting at the adrenoceptors) in a patient with asthma? 
Select and explain. 
A. Pharmacologic antagonist, B. Partial agonist, C. Physiologic antagonist, D. Chemical antagonist
C: Physiologic antagonist
Answer: C: Physiologic antagonist 
Explanation: Physiological / functional antagonism
The two drugs act on different receptors or by different mechanisms, but have opposite overt effects on the same physiological function. i.e. have pharmacological effects in opposite direction, e.g.

Histamine and adrenaline on bronchial muscles and on BP.
Hydrochlorothiazide and amiloride on urinary K+ excretion.
Glucagon and insulin on blood sugar level.

Key Concept: 
Drugs producing opposite action by acting on diﬀerent receptors are called physiological antagonists.
Reference: Essentials of Medical Pharmacology Eighth Edition KD TRIPATHI page no 68