Possible Clues:

• Caught in a way to settle dispute: drugs, perhaps
• Charlie stops negotiating drugs course
• Negotiation about constant treatment regime
• Attempt to resolve dispute about Charlie's treatment
• Intervention when cold is caught -- this being taken?
• Commitment initially doubled to supply a drug
• Diplomatic activity involving consular leader's treatment
• Good offices for the injection of cold drugs etc.
• See 17-Across