Polyethylene glycol (PEG) laxatives and starch-based thickeners: potential interactive effect when mixed, leading to an increased risk of aspiration
MHRA advise to avoid directly mixing together PEG laxatives and starch-based thickeners as the thickening action can be counteracted resulting in a thin watery liquid, and patients with swallowing difficulties (dysphagia) are potentially at greater risk of aspiration.
Source:
Medicines and Healthcare products Regulatory Agency