- Levocetirizine, the R-enantiomer of Cetirizine is a non-sedating, new generation antihistamine with a high affinity for and occupancy of the H1-receptor.
- It blocks the effects of histamine, a key mediator of allergic inflammation, which causes runny nose, itching, sneezing, and watery eyes.
- It has abridged anti-cholinergic and anti-serotonin effects and therefore is singled out in patients with allergies since it does not over dry respiratory secretions.
Phenylephrine (Nasal decongestant)
- Phenylephrine is a sympathomimetic primarily used as a systemic nasal decongestant.
- The mechanism by which decongestants bring off their action is by activation of postjunctional alpha 1-adrenergic receptors found on precapillary and post-capillary blood vessels of the nasal mucosa.
- Activation of these receptors by distinct binding of the sympathomimetic agent to the binding site of the receptor or by the enhanced release of norepinephrine leads to vasoconstriction.
(Note: Vasoconstriction leads to shrinkage of the tissue by decreasing blood flow through the nasal mucosa.)
- A non-steroidal anti-inflammatory drug, most commonly used centrally acting analgesic, and its use as an antipyretic to treat fever, headache, and body ache are ubiquitous.
- Paracetamol does not alter acid the base balance, depress respiration, or cause gastric irritation.
- A fixed-dose combination of Paracetamol, Phenylephrine, and Levocetirizine is safe and effective in the treatment of Common Cold and Allergic Rhinitis in children.
- >50% reduction in symptom score and the majority of patients had complete relief from the symptom.