<unk>  may cause side effects such as headache, reflex bradycardia, excitability, restlessness and cardiac arrhythmias.<unk>  is not suggested for use in patients with hypertension. Heart The primary side effect of<unk>  is high blood pressure.<unk> ople with high blood pressure are typically advised to avoid products containing it. Because this medication is a sympathomimetic amine without beta-adrenergic activity, it does not increase contractility force and output of the cardiac muscle. It may increase blood pressure resulting in a slow heart rate through stimulation of vascular (likely carotid) baroreceptors. A common side effect during IV administration is reflex bradycardia. The low concentration eye drops do not cause blood pressure changes and the changes with the higher dose drops do not last long. Other Prostatic hyperplasia can also be worsened by use, and chronic use can lead to rebound hyperemia.<unk> ople with a history of anxiety or panic disorders, or on anticonvulsant medication for epilepsy should not take this substance. The drug interaction might produce seizures. Some patients have been shown to have an upset stomach, severe abdominal cramping, and vomiting issues connected to taking this drug.<unk>  is pregnancy category C. Due to the lack of studies done in animals and in humans, it is not known whether there is harm to the fetus.<unk>  should only be given to pregnant women who have a clear need. Extended use may cause rhinitis medicamentosa, a condition of rebound nasal congestion. Interactions The increase in blood pressure effect of<unk>  may be increased by drugs such as monoamine oxidase inhibitors, tricyclic antidepressants, and hydrocortisone. Patients taking these medications may need a lower dose of<unk>  to achieve a similar increase in blood pressure. Drugs that may decrease the effects of<unk>  may include calcium channel blockers, ACE inhibitors and benzodiazepines. Patients taking these medications may need a higher dose of<unk>  to achieve a comparable increase in blood pressure.
Phenylephrine
Prazosin
Terazosin
Acebutolol
Doxazosin
Oxymetazoline
Metergoline
Clonidine