Administer with caution to patients with glaucoma, prostatic hypertrophy, hyperthyroidism, cardiovascular disorders, diabetes mellitus, urinary retention, increased intraocular pressure and stenosing peptic ulcer.
Antihistamines are not recommended in patients with bronchial asthma because their drying effects may thicken mucus secretions and impair expectoration.
Administer paracetamol with caution to patients with preexisting anemia since cyanosis may not be apparent despite dangerously high blood concentrations of methemoglobin.
Paracetamol may cause allergic-type reactions eg, anaphylaxis in susceptible individuals. Discontinue use if hypersensitivity reactions occur.
Phenylpropanolamine should not be administered concomitantly with MAO inhibitors, rauwolfia alkaloids, tricyclic antidepressants, ganglionic blocking agents and halogenated hydrocarbon general anesthetics.
Antihistamines have additive effects with central nervous system (CNS) depressants such as alcohol, hypnotics, sedatives and tranquilizers, but may diminish the actions of oral anticoagulants.
Concomitant administration of paracetamol and phenothiazine may cause severe hypothermia.