Phenylephrine Health Dictionary

Drugs that are used to relieve nasal congestion commonly in people with upper respiratory tract infections.

They work by narrowing blood vessels in the membranes lining the nose.

This action reduces swelling, inflammation, and the amount of mucus produced by the lining.

Common drugs include ephedrine, oxymetazoline, and phenylephrine.

Small amounts of these drugs are present in many over-thecounter cold remedies.

Taken by mouth, decongestant drugs may cause tremor and palpitations.

Adverse effects are unlikely with nose drops, but if taken for several days they become ineffective and symptoms may then recur or worsen despite continued treatment.... decongestant drugs

A group of drugs used to treat uveitis and to dilate the pupil during examination of the inside of the eye and for surgery. Mydriatics work by relaxing the circular muscles of the iris, causing the pupil to dilate. Common mydriatic drugs include tropicamide, cyclopentolate, homatropine, and phenylephrine. (See also cycloplegia; miotic drugs.)... mydriatic drugs

(MAOI) a drug that prevents the activity of the enzyme *monoamine oxidase (MAO). MAO inhibitors include phenelzine, isocarboxazid, and tranylcypromine. These drugs are irreversible inhibitors of monoamine oxidase A, whose use as antidepressants is now restricted because of the severity of their side-effects. These include interactions with other drugs (e.g. ephedrine, phenylephrine) and with foods or drinks containing *tyramine (e.g. cheese or red wine) to produce a sudden and dangerous increase in blood pressure. *Moclobemide is a reversible inhibitor of monoamine oxidase A (RIMA), with less severe side-effects. See also selegiline.... mao inhibitor

n. a drug that causes the pupil of the eye to dilate. Examples are *atropine, *cyclopentolate, and *phenylephrine. Mydriatics in the form of eye drops or ointments are used to aid examination of the eye and to treat some eye inflammations such as iritis and cyclitis.... mydriatic

n. a prolonged (greater than four hours) and usually painful erection of the penis. Ischaemic priapism is associated with blood disorders (such as sickle-cell disease or leukaemia) or haemodialysis or it can result from administration of drugs used to treat erectile dysfunction, such as *papaverine or intracorporeal *alprostadil. It requires urgent decompression by draining the blood from the corpora cavernosa of the penis with a 19 SWG butterfly needle and instilling a *vasoconstrictor (e.g. phenylephrine). If aspiration fails surgical shunts may be necessary. An unrelieved ischaemic priapism results in eventual complete fibrosis of the spongy tissue of the corpora and no further erections are possible. A penile *prosthesis may be appropriate in this situation. Nonischaemic priapism is usually caused by perineal trauma resulting in an arteriovenous *fistula. This does not result in tissue damage. *Embolization of the site of vascular injury is usually necessary.... priapism

adj. having the effect of stimulating the *sympathetic nervous system. The actions of sympathomimetic drugs are adrenergic: they act on alpha or beta *adrenoceptors. Alpha-adrenergic stimulants (alpha agonists) stimulate alpha receptors. They include *vasoconstrictors (e.g. *ephedrine, *phenylephrine, *metaraminol), used to treat nasal congestion and severe hypotension, and the selective ?2 agonists *apraclonidine and *brimonidine, which are used in the treatment of glaucoma. Beta-adrenergic stimulants (beta agonists) stimulate ?1 and/or ?2 adrenoceptors. ?2 agonists such as *salbutamol, *salmeterol, and *terbutaline relax bronchial smooth muscle and are used as *bronchodilators. Some ?2 agonists, including salbutamol, relax uterine muscle and are sometimes used in the treatment of premature labour (see tocolytic). ?1 agonists (e.g. *dobutamine) stimulate ?1 receptors in the heart and are therefore used for their *inotropic effects.... sympathomimetic

n. an agent that causes narrowing of the blood vessels and therefore a decrease in blood flow. Vasoconstrictor drugs are alpha agonists (see sympathomimetic): they are used to raise the blood pressure in disorders of the circulation, shock, or severe bleeding and to maintain blood pressure during surgery (e.g. *ephedrine, *metaraminol, *phenylephrine). Some vasoconstrictors (e.g. ephedrine, *xylometazoline) have a rapid effect when applied to mucous membranes and may be used to relieve nasal congestion. If the blood pressure rises too quickly headache and vomiting may occur. A vasoconstrictor is often added to local anaesthetic solutions used in dentistry to prolong their effectiveness.... vasoconstrictor