Drugs may be categorized as 'red' for a variety of different reasons. Depending on how a gene variant impacts a specific drug’s metabolism, you may experience various combinations of increased or decreased effectiveness or side effects. In general, if a drug is categorized as 'red', there is a likelihood that you may not experience the expected effectiveness and/or it may be less tolerable or safe for you, and hence the overall effect is expected to be negative (and in some cases, may be hazardous) for you versus using an alternative option.
Multiple other factors (including age, overall health and medical conditions, organ function, and expected drug-drug interactions for example) may either decrease or increase the overall impact of having a specific gene variant. Drugs categorized as 'yellow' may be appropriate treatment options in some cases, however closer monitoring to ensure effectiveness and tolerability may be recommended. It is critical to read the associated recommendations (e.g. an alternate dose may be required to produce the desired response) in discussion with your healthcare provider(s). It is never recommended to abruptly stop a medication, even if it is classified as 'red' on your report, before consulting with your healthcare provider(s).