In ecology, commensalism is a class of relationship between two organisms where one organism benefits without affecting the other. It compares with mutualism, in which both organisms benefit, amensalism, where one is harmed while the other is unaffected, and parasitism, where one benefits while the other is harmed.n ecology, commensalism is a class of relationship between two organisms where one organism benefits without affecting the other. It compares with mutualism, in which both organisms benefit, amensalism, where one is harmed while the other is unaffected, and parasitism, where one benefits while the other is harmed.
Drug interactions also may occur when two drugs that have similar (additive) effects or opposite (canceling) effects on the body are administered together. For example, there may be major sedation when two drugs that have sedation as side effects are given, for example, narcotics and antihistamines.
Abstract. Drugs may interact with other drugs or any diet or dietary supplement taken at the same time. Interactions may be pharmacodynamic in which interaction is close to the target organ and involves direct antagonism or addition of pharmacological properties.rug interactions are usually described as pharmacodynamic (where changes in drug action occur in the area of the target tissue) or pharmacokinetic (when one drug affects the absorption, distribution or excretion of another).