| Term 
 | Definition 
 
        | drugs that are obtainable without a prescription.  |  | 
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        | Term 
 | Definition 
 
        |   an altered or modified action or effect of a drug as a result of interaction with one or multiple drugs.   |  | 
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        | Term 
 | Definition 
 
        |   an undesirable drug effect that ranges from mild untoward effects to severe toxic effects, including hypersensitivity reaction and anaphylaxis.   |  | 
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        | Term 
 | Definition 
 
        |   a chemical or physical reaction that occurs among two or more drugs in vitro (outside the body, i.e. syringe, IV bag, etc.)   |  | 
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        | Term 
 | Definition 
 
        |   the sum of the effects of two drugs.   |  | 
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        | Term 
 | Definition 
 
        |   the clinical effect is substantially greater than the combined effect of the two.   |  | 
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        | Term 
 | Definition 
 
        |   two drugs that are administered together which have opposite effects and cancel the effect of one another.   |  | 
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        | Term 
 
        | Photosensitivity (drug-induced) |  | Definition 
 
        |   a skin reaction caused by exposure to sunlight.   |  | 
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