FOLCOFEN

Diphenhydramine is an ethanolamine-derivative antihistamine. It is an antihistamine with anticholinergic and marked sedative effects. It acts by inhibiting the effects on H₁-receptors. Diphenhydramine is effective in reducing sleep onset (i.e., time to fall asleep) and increasing the depth and quality of sleep.

Guaifenesin is an expectorant the action of which promotes or facilitates the removal of secretions from the respiratory tract. The precise mechanism of action of guaifenesin is not known; however, it is thought to act as an expectorant by increasing the volume and reducing the viscosity of secretions in the trachea and bronchi. In turn, this may increase the efficiency of the cough reflex and facilitate removal of the secretions. Guaifenesin is over-the-counter drug for the treatment of cough and common cold.

Pholcodine is an opioid that has been widely used for the treatment of non-productive cough in children and adults. Pholcodine is a cough suppressant with mild sedative but little analgesic activity. Additionally pholcodine is a marker for sensitization to neuromuscular blocking agents (NMBA) and is intended for use as a diagnostic tool in NMBA-induced anaphylaxis.