The prefix of "co-" is used for many combination drugs, including opioid with paracetamol or aspirin analgesics (e.g., Co-codamol, Co-codaprin, Co-dydramol, Co-proxamol). The other commonly-encountered opioid combination is the anti-diarrhoeal, non-analgesic mixture of diphenoxylate and atropine, Co-phenotrope (a.k.a. Lomotil). Also antibiotics (e.g., Co-fluampicil and Co-trimoxazole), drugs to lower blood pressure (e.g., Co-tenidone), diuretics (e.g., Co-amilofruse and Co-amilozide), gastrointestinal drugs (e.g., Co-danthrusate) and anti-Parkinsonism agents such as Co-careldopa, Co-beneldopa, and others (e.g., Co-cyprindiol).
This has resulted in an interesting situation in countries such as Australia. While the British Pharmacopoeia and BANs are the official pharmacopoeia/names defined by legislation in these countries, the former-BANs continue to be used, purportedly because of the difficulty of changeover. Despite the importance of the BP there appears to be little or no movement in the direction of changing these names.