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.
If you use 2 or more drugs at the same time, the way your body processes each drug can change. When this happens, the risk of side effects from each drug increases and each drug may not work the way it should. This is called a drug-drug interaction.onsteroidal anti-inflammatory drugs (also called NSAIDs) stop cyclooxygenase enzymes (also called COX enzymes) in your body from working. COX enzymes speed up your body's production of hormone-like substances called prostaglandins. Prostaglandins cause the feeling of pain by irritating your nerve endings.