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Drug Caution Code - Code C

Code C: Caution

Consult your Pharmacist if you have glaucoma, diabetes, hypertension (high blood pressure), hyperthyroidism (goiter), prostate trouble, or if you take antidepressant drugs.

This code covers the products containing the Oral Decongestants:

These are sympathomimetic amines with alpha-adrenergic receptor action which causes vasoconstriction of nasal and pharyngeal mucosa to produce a decongestant effect. Other systemic blood vessels will also be constricted which causes side effects. Oral decongestant products are safe to use in recommended doses in healthy individuals but may have adverse effects in persons with heart disease, hypertension, diabetes, hyperthyroidism, urinary retention or an enlarged prostate. They are contraindicated in persons receiving or having received MAO inhibitors in the past 2 weeks. The therapeutic effectiveness of phenylephrine as a nasal decongestant has been questioned, especially at the usual oral dose. (eg. Some Neo Citran R products) Tricyclic antidepressants have an additive sympathomimetic effect with phenylephrine. The elderly are more likely to have adverse reactions to sympathomimetics. Overdose may cause hallucinations, convulsions, CNS depression and death. There is an abuse potential with pseudoephedrine using high doses for a stimulant effect.


Patients with ANGLE CLOSURE GLAUCOMA should not use decongestants. Mydriasis (dilation of pupil) occurs with sympathomimetics and intraocular pressure may increase. This interaction is rare since only 5-10% of glaucoma patients have narrow angle glaucoma, but is still very important. Patients with open angle glaucoma may have a slight increase in introcular pressure. Short term or occasional use is not contraindicated in patients with well-controlled open angle glaucoma.

Diabetes Mellitus

Sympathomimetic decongestants have a hyperglycemic effect and cause an elevation in blood glucose. Also, when combined with sulfonylureas there is an increase in blood sugar and there is a danger of hyperglycemia.
Short term or occasional use of sympathomimetics is not contraindicated. However, blood glucose should be closely monitored.


Oral decongestants have the potential to elevate diastolic and systolic pressure by beta stimulation of the heart to increase cardiac rate and output and by peripheral vasoconstriction. They are contraindicated in patients with severe hypertension or severe coronary disease. Pseudoephedrine is considered to be the safest agent since its decongestant activity occurs at approximately half the dose required to significantly increase blood pressure. Tachycardia and palpitations are still frequent side effects particularly with prolonged use or if administered more often than recommended. Phenylephrine causes hypertension as a relatively common side effect. Phenylpropanolamine and ephedrine increase diastolic pressure and should be avoided by hypertensive patients.

Prostatic Hypertrophy

Oral decongestants should be used with caution in patients with prostatic hypertrophy. Sympathomimetic activity may precipitate or aggravate urinary retention.


The cardiac stimulating properties of sympathomimetics can aggravate the cardiac symptoms of hyperthyroidism. Also, central nervous system stimulation causes an increased secretion of thyroid hormone which is potentially dangerous to a hyperthyroid patient.


Oral decongestants are contraindicated in patients taking MAO inhibitor antidepressants. Concurrent use may cause cardiac arrhythmias, severe hypertensive crisis and even death. A two week wash out period is required for MOA inhibitors and 2 days for moclobemide. Tricyclic antidepressants facilitate and increase the sympathomimetic response of phenylephrine. Increased cardiovascular eflects can lead to arrhythmias, tachycardia and hypertensive crisis. Phenylephrine should be avoided by those taking tricyclic antidepressants.

Treatment Alternatives

Some treatment alternatives to relieve nasal congestion are: If the patient is not fluid restricted, drink at least 8 to 10 glassfuls of fluid each day. Hot fluids seem to work better but avoid those containing caffeine. Increase humidity with humidifiers or vaporizers. Take frequent showers and keep the door closed to increase humidity. Cough suppressants and expectorants have fewer adverse effects and can be used to relieve those symptoms. Non-medicated saline nose drops can be used. Topical nasal decongestants can be used for a short time (not more than 3 days) and only as directed. Increased doses can lead to systemic effects.

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