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.
Medication interactions result when a medication is used with another medication or substance that modifies the drugâs expected action. Medication interactions can develop between food and drugs, between prescribed and over-the-counter drugs including herbal products, and as drug-to-drug interactions.A medication interaction can increase or decrease the drugâs effect through changes in absorption, distribution, metabolism, or excretion.edication interactions can develop between food and drugs, between prescribed and over-the-counter drugs including herbal products, and as drug-to-drug interactions. A medication interaction can increase or decrease the drugâs effect through changes in absorption, distribution, metabolism, or excretion.