For lignocaine, which condition is a contraindication for its use?

Allergy or hypersensitivity to lignocaine is a contraindication for its use because if a patient has a known allergy to this medication, administering it could provoke a severe allergic reaction. Hypersensitivity can lead to adverse effects that may range from localized reactions, such as rash or itching, to life-threatening systemic reactions, such as anaphylaxis. It's critical to avoid administering medications that the patient is allergic to in order to prevent such dangerous responses.

In contrast, the other conditions listed may require caution or dose adjustment but do not universally contraindicate the use of lignocaine. For instance, hypotension may be managed during treatment without necessarily ruling out lignocaine, while severe dehydration and sepsis can sometimes increase the risk of complications but do not outright prevent its use. Nonetheless, a thorough assessment of each patient should be conducted, considering all factors involved in their specific situation.