ClinicalUseIssue may convey information of 5 distinct types, as announced by the value set ClinicalUseIssueType attached to the "type" element.

However, only 4 of these 5 are explicitly supported by a dedicated backbone: indication, contraindication, interaction and undesirableEffect. The fith one "warning" is not represented in the resource. At the minimum, it should  be possible to convey a warning as a CodeableConcept (either one or more coding, or only the text).

Hence this suggested change:

1) Add this element to the resource:

warning

• CodeableConcept
• summary
• 0..1 
• Definition: "Specifics for when this is a warning"

2) In the Boundaries & Relationships section, add one fith bullet to the bullet list:

• Warning: A warning or precaution for use of a medicinal product, medical device or procedure.