Rebound congestion is a danger when locally applied nasal preparations are used for too long or in large doses. Blood vessels in the mucous membranes shrink when the drug is applied. only to swell to greater-than-normal sizes when it wears off. This swelling can be permanent. Irreversible damage to cilia can lead to their paralysis and failure to move mucus out of the nasal passages. Hence, the need for Coronary Calcium Score.
Permanent congestion and ‘addiction’ to nasal sprays ensue. Where circulatory insufficiency is undesirable, in gangrenous states. Raynauds syndrome. vasoconstrictors are contra-indicated as they further impair circulation in the extremities. NA is avoided as a heart stimulant for this reason. Excessive beta-one heart stimulation leads to tachydysrhythmias which. in extreme can be fatal. Asthmatics employing sympathomimetic bronchodilators usually use agents which selectively stimulate beta-two receptors but. if overdosed. these drugs are capable of acting on beta-one receptors to produce dysrhythmias which can prove fatal. Secondary diabetes mellitus and hyperthyroidism can occur.
