Hi, Yes, if taken together these may cause blackouts . Consuming double gin while on two tablets of piriton (chlorpheniramine maleate) may increase side effects such as dizziness, drowsiness, confusion, difficulty concentrating, impaired thinking, judgment, and motor coordination. You should avoid taking alcohol while being treated with piriton. Do not use more than the recommended dose of piriton, and avoid driving after consuming alcohol or alcohol-containing beverages such as double gin . Feedback is appreciated. Concurrent use of chlorphenamine and hypnotics or anxiolytics may cause an increase in sedative effects, therefore medical advice should be sought before taking chlorphenamine concurrently with these medicines. Hope I have answered your query. Let me know if I can assist you further. Take care Regards, Dr Mohammed Taher Ali, General & Family Physician