Dihydrocodeine is an analgesic with opioid that is used in conjunction or as an alternative to Codeine in the treatment of cough, severe dyspnea, and severe pain. 5 to 15 mg/kg IV load at a rate of 50 mg/minute or less, followed by a continuous infusion of 0.5 to 5 mg/kg/hour IV. An additional loading dose of 5 to 10 mg/kg may be given. Promethazine VC with Codeine Oral Solution is indicated for the temporary relief of coughs and upper respiratory symptoms, including nasal congestion, associated with allergy or the common cold in patients 18 years of age and older. Promethazine and Codeine - Clinical Pharmacology Mechanism of Action. Codeine. Codeine is an opioid agonist relatively selective for the mu-opioid receptor, but with a much weaker affinity than morphine. For the treatment of infections due to Mycobacterium sp., including tuberculosis infection. NOTE: All patients receiving isoniazid therapy should also receive pyridoxine daily. Oral route (Tablet;Syrup) Promethazine hydrochloride should not be used in pediatric patients less than 2 years old because of the potential for fatal respiratory depression. Doctors give trusted answers on uses, effects, side-effects, and cautions: Dr. Andrews on delsym and benadryl: Either the recommended amount based on weight through the directions on the box or following your doctors recommendations if the recommended dose they made is higher. Promethazine is a first-generation antihistamine. It is used to treat allergies, trouble sleeping, and nausea. It may help with some symptoms associated with the common cold. It may also be used for sedating people who are agitated or anxious. DESCRIPTION. Each 5 mL (one teaspoonful), for oral administration contains: Promethazine hydrochloride 6.25 mg; codeine phosphate 10 mg in a flavored syrup base with a pH between 4.8 and 5.4. Codeine is an opiate used to treat pain, as a cough medicine, and for diarrhea. It is typically used to treat mild to moderate degrees of pain. Greater benefit may occur when combined with paracetamol (acetaminophen) or a nonsteroidal anti-inflammatory drug (NSAID) such as aspirin or ibuprofen. Evidence does not support its use for acute cough.