Chlorpheniramine, dextromethorphan and phenylephrine is a combination with synergistic action used to treat cough, runny or stuffy nose, sneezing, itching, and watery eyes caused by allergies, the common cold, or the flu. Cough that is caused by smoking, asthma, or emphysema will not be treated by this syrup.
- Coughs and upper respiratory tract symptoms
- Nasal congestion
- Allergy or common cold
Mechanism of Action
It is rapidly absorbed from GIT and is extensively metabolised to dextrorphan (active metabolite) in liver. The half-life is 3-6 hours. Chlorphenamine maleate is a H1 receptor antagonist used in allergic reactions, hay fever, rhinitis, urticaria, and asthma. This blocks the action of endogenous histamine, which subsequently leads to temporary relief of the negative symptoms brought on by histamine.
It is well orally absorbed with a plasma protein binding of 72%. It is metabolised in liver with a half-life of 21-27 hours.
Phenylephrine is categorized as sympathomimetic drug and mimics the actions of epinephrine (commonly known as adrenaline) or norepinephrine. Phenylephrine selectively binds to alpha-1 receptors which cause blood vessels to constrict leads to nasal decongestant action.
When orally administered, the bioavailability was found to be 38%. Peak concentration reaches between 0.5 and 2 hours after administration. No protein‐binding data in humans are available. It undergoes extensive biotransformation in the gut wall and the liver. Half‐lives is relatively short, approximately 2.5 hours. Reduced metabolism of Phenylephrine occurs with concurrent administration of monoamine oxidase inhibitors.
- Severe hypertension
- Ventricular tachycardia
- Severe coronary artery disease
- Chronic bronchitis
- Blurred vision
- Dry mouth
- Stomach pain
- Skin rash or itching