Pseudoephedrine

An OTC sympathomimetic commonly used as a nasal decongestant or for opening obstructed eustachian ostia.

Used in the symptomatic treatment of reactive airway disease; however, appears to be ineffective as a bronchodilator.

Also used for treatment of ejaculatory dysfunction and as a starting material for illicit drug manufacturing.

Abuse and addiction to OTC stimulants does occur, particularly in those with eating disorders or erratic work hours, such as truck drivers. Associated with myocardial injury and withdrawal symptoms in this setting.

Concern about the coadministration of other sympathomimetic agents because of the possibility of additive effects and increased toxicity.

Pressor effects of pseudoephedrine are more pronounced in:

• Hypertensive pts

• Pts taking β-adrenergic blocking drugs

• Pts taking SNRIs

May increase heart irritability

MAO inhibitors, by increasing the quantity of NE, potentiate pseudoephedrine’s indirect pressor effects; infrequently, a hypertensive crisis may result.

May also reduce the antihypertensive effects of reserpine and methyldopa.

Acts directly on α- and, to a lesser degree, β-adrenergic receptors. Has an indirect effect by releasing NE from its storage sites.

α -adrenergic effects result from inhibition of the production of cAMP by inhibiting the enzyme adenylyl cyclase, whereas β-adrenergic effects result from stimulation of adenylyl cyclase activity.

Acts directly on α-receptors in the mucosa of the respiratory tract, producing vasoconstriction; this shrinks mucous membranes, thus reducing edema and congestion.

May relax bronchial smooth muscle by stimulating β-adrenergic receptors, but this effect is not consistent.

Readily and completely absorbed; elimination is predominantly renal and pH-dependent.

Direct and indirect sympathomimetic

Half-life is 6 h for standard preparation and 12 h for extended-release form.

Adults and children ≥12 y of age: 60 mg q4–6h with a maximum dosage of 240 mg/d.

Children 6–11 y of age: 30 mg q4–6h with a maximum dosage of 120 mg/d.

Children 2–5 y of age: 15 mg q4–6h with maximum dosage of 60 mg/d.

Children <2 of age: No USA FDA-approved dosing.