11. Paracetamol is sometimes combined with phenylephrine hydrochloride. 12. The surgeon instructed a nurse to instill phenylephrine drops in the nose to help stop bleeding. 13. Pseudoephedrine acts indirectly on the adrenergic receptor system, whereas phenylephrine and oxymetazoline are direct agonists. 14. Phenylephrine hydrochloride at 0.25 % is used as a vasoconstrictor in some suppository formulations.15. Tropicamide and phenylephrine are used in medicine as mydriatics to dilate pupils for retinal and lens examination. 16. Because of its vasoconstrictive effect, phenylephrine can cause severe necrosis if it infiltrates the surrounding tissues. 17. For example, pseudoephedrine is taken orally and phenylephrine is topically applied to the nasal passages or eyes. 18. Pseudoephedrine and loratadine-montelukast therapy were found to be significantly more effective than both phenylephrine and placebo. 19. Drugs that may decrease the effects of phenylephrine may include calcium channel blockers, ACE inhibitors and benzodiazepines. 20. Patients taking these medications may need a higher dose of phenylephrine to achieve a comparable increase in blood pressure.
