Several herbs may help relieve the swelling and stuffiness that make sinusitis, the common cold, hay fever, or other respiratory complaints so uncomfortable. Most of these herbs work by opening up clogged nasal passages to ease breathing.

Epidemiologic studies suggest that the prevalence of allergic rhinitis is rising worldwide. Several reports, in fact, indicate increasing trends in the prevalence especially in developing countries, likely related to the environment and climate changes and the adoption of an urbanized Western lifestyle.

Ephedra free decongestant
In response to concerns regarding the safety of ephedra-containing dietary supplements, manufacturers have marketed "ephedra-free" products. Many of these contain synephrine, a sympathomimetic amine from the plant Citrus aurantium. Synephrine is structurally similar to ephedrine and has vasoconstrictor properties.
   Immature bitter orange fruit and its extracts have been introduced into the market as an alternative to Ephedra in weight loss products. However, the safety of the immature bitter orange fruit and its extracts is a debated argument due to the presence of synephrine, a constituent known as a sympathomimetic agent.

Pseudoephedrine as a decongestant
Pseudoephedrine controls nasal allergy symptoms just as well as the more expensive prescription drug Singulair, also known by its generic name, montelukast. In fact, as a nasal decongestant, pseudoephedrine may provide better relief. While pseudoephedrine is known to be an effective treatment for nasal congestion caused by allergies, it is not thought to be particular useful against other symptoms. Moreover, some people who take pseudoephedrine experience side effects such as insomnia and nervousness. The study, which appears in the February 2006 issue of the Archives of Otolaryngology - Head and Neck Surgery, involved 58 adults allergic to ragweed who were randomized to receive a once-daily morning dose of pseudoephedrine or montelukast for 2 weeks. Treatment with either agent provided similar and significant improvements in all aspects of quality of life. The tolerability of the agents was similar with no increase in insomnia or nervousness seen with pseudoephedrine. The researchers chalk this up to pseudoephedrine being given as one higher dose in the morning, rather than as two or more lower doses given throughout the day as is often done.

Oxymetazoline
Pulm Pharmacol Ther. 2014 Feb. Effectiveness of 0.05% oxymetazoline (Vicks Sinex Micromist) nasal spray in the treatment of objective nasal congestion demonstrated to 12 h post-administration by magnetic resonance imaging. This study aimed to assess the qualitative and quantitative utility of MRI imaging to illustrate the magnitude and duration of the effect of a standard 100 μg dose of oxymetazoline in a commercially available formulation that also contains aromatic oils. This was a randomized, open label, single dose, parallel group study in 21 adult male and female subjects who reported moderate to severe nasal congestion due to acute upper respiratory tract infection or hay fever. MRI scans were acquired using a 3T Philips Achieva scanner with a 16 channel head receive coil. High resolution MRI scans of the nasal turbinates were obtained immediately prior to dosing (baseline) and at approximately 1, 8, 10, 11, and 12 h after dosing. The efficacy variables of primary interest were inferior turbinate total volume at 8 and 12 h post-dosing. The secondary efficacy variables analysed were inferior turbinate total volume at 1, 10, and 11 h post-dosing, middle turbinate total volume at 1, 8, 10, 11, and 12 h post-dosing. Changes from baseline volumes measured for the inferior and middle turbinates of subjects receiving the oxymetazoline formulation showed significant (P < 0.05) decreases at all times up to and including 12 h post-administration. No significant decreases from baseline were detected in subjects receiving a sham 'spray' (untreated control - spray bottles with no spray solution). Statistical ANCOVA results of inferior and middle turbinate volume indicated significant differences (P < 0.05) at all measurement points up to and including 12 h post-administration between the oxymetazoline treatment group and the untreated control with the only exception the middle turbinate volume at 10 h (P = 0.0896). The significant changes were likely to be clinically relevant though this was not measured in the study. No AEs were reported during this study and no other safety evaluations were made. This study showed that MRI assessment of nasal congestion in human volunteers is a robust, repeatable and viable measurement technique. The application of a 100 μg Vicks Sinex Micromist(®) nasal decongestant (0.05% oxymetazoline solution) delivered a highly significant reduction in inferior and middle turbinate volumes compared with the application of a control, measurable by the MRI method up to and including a 12 h post-dose scan.

Nasal Congestion and time of day
Nasal congestion, which has been shown to cause sleep-disordered breathing, is thought to be primarily responsible for rhinitis-related sleep disorders. The severity of nasal congestion follows a circadian rhythm, being worst at night and in the early morning. Chronotherapy is the study of the effects of administration time on the safety and efficacy of drug therapy based on circadian influences on the pharmacokinetics and pharmacodynamics of medications. Chronotherapy studies in allergic rhinitis suggest there are benefits to nighttime dosing of antiallergy medications. For example, the antihistamine mequitazine has shown improved efficacy when administered in the evening compared with morning dosing. More study is needed to determine whether this is a class effect. Leukotriene receptor antagonists are indicated for evening administration; these drugs significantly improve nighttime rhinitis symptoms. Intranasal corticosteroids administered in the morning have demonstrated efficacy in improving nighttime symptoms.

Pregnancy
A woman's use of decongestant medications in the first trimester of pregnancy may raise her child's risk of certain rare birth defects.

Questions
I recently bought a book called 'The complete guide to vitamins herbs and supplements' by winifred conkling w/ David  y. Wong, m.d. consulting editor. In it concerning impotence it said some over-the counter antihistamines and decongestants can cause temporary impotence, but can they also cause testosterone levels to drop ,if so can the effects of long term use of these be reversed ?.
   It is true that in some people decongestants and antihistamines can cause impotence, but it is unlikely that it is due to testosterone. Many people find sexual enhancement with herbs and supplements that can reverse this condition.