Decongestants sympathomimetics

The MAOIs interfere with the hepatic metabolism of many prescription and nonprescription (over-the-counter) drugs and may potentiate the actions of their pharmacological effects (i.e., cold decongestants, sympathomimetic amines, general anesthetics, barbiturates, and morphine). 

Tetrahydro2oline [84-22-0] 2-(l,2,3,4-tetrahydro-l-naphthyl)2-imida2olin, (Tysine, Visine) (40), a sympathomimetic and nasal decongestant, is made by the condensation of 1,2,3,4-tetrahydro-l-naphthoic acid or its methyl ester with 1,2-ethylenediamine. 

Additive sympathomimetic effects may develop when decongestants are administered with other sympathomimetic drug s (see Chap. 22). Use of the nasal decongestants with the MAOIs may cause hypertensive crisis. Use of a decongestant with beta-adrenergic blocking dragp may cause hypertension or bradycardia. When ephedrine is administered with theophylline, the patient is at increased risk for theophylline toxicity. 

Decongestants such as OTC pseudoephedrine are sympathomimetic agents that constrict capacitance vessels in the nasal turbinates.17 Decongestants effectively reduce nasal congestion and to some extent rhinorrhea associated with AR.8,12 The recommended dose of pseudoephedrine is 30 to 60 mg every 4 to 6 hours for a maximum daily dose of 240 mg.15 Systemic adverse effects such as irritability, dizziness, headache, tremor, tachycardia, and insomnia can occur. Additionally, use is associated with increased blood pressure and intraocular pressure and urinary obstruction.8,12... 

Topical and systemic decongestants are sympathomimetic agents that act on adrenergic receptors in the nasal mucosa to produce vasoconstriction, shrink swollen mucosa, and improve ventilation. Decongestants work well in combination with antihistamines when nasal congestion is part of the clinical picture. 

Phenylephrine (27) is a low-potency sympathomimetic amine used as a decongestant. Solutions become coloured due to an auto-oxidation accelerated by light. In a series of experiments, aqueous solutions of the hydrochloride were left under a UV lamp until a tan colour developed. HPLC analysis showed four main products of which one was identified as adrenaline (19). Even after prolonged irradiation, there was never more than 2% adrenaline in the solution. It was assumed that the catecholamine was removed as it formed by further reaction to adrenochrome and melanine, which accounted for the colour [34],... 

Phenylephrine is a nasal decongestant that mimics the sympathetic system, thereby increasing the heart rate and blood pressure. It may aggravate conditions such as diabetes, hypertension and glaucoma. Patients with hypertension, ischaemic heart disease, hyperthyroidism, diabetes and glaucoma are therefore given topical nasal sympathomimetics rather than systemic sympathomimetics. Both topical and systemic sympathomimetics are contraindicated in patients taking monoamine oxidase inhibitors, because concurrent administration of the two products may lead to a hypertensive crisis. 

Vasoconstriction. Local application of a-sympathomimetics can be employed in infiltration anesthesia (p. 204) or for nasal decongestion (naphazoline, tetra-hydrozoline, xylometazoline pp. 90, 324). Systemically administered epinephrine is important in the treatment of anaphylactic shock for combating hypotension. 

Most interactions listed apply to sympathomimetics when used as vasopressors however, consider the interaction when using the nasal decongestants. 

Pharmacology Epinephrine, a direct-acting sympathomimetic agent, acts on and receptors. Topical application, therefore, causes conjunctival decongestion (vasoconstriction), transient mydriasis (pupillary dilation), and reduction in intraocular pressure (lOP). It is believed lOP reduction primarily is caused by reduced aqueous production and increased aqueous outflow. The duration of decrease in lOP is 12 to 24 hours. 

Pseudoephedrine (Sudafed, Novafed, Afrinol, Others) [OTC] [Decongestant/Sympothomimetic] Uses Deconge tant Action Stimulates a-adren gic rec tors w/ vasoconstriction Dose Adults. 30-60 mg PO q6—8h Peds. 4 mg/kg/24 h PO qid -1- in renal insuff Caution [C, +] Contra Poorly controlled HTN or CAD, w/MAOIs Disp Tabs, caps, Liq SE HTN, insomnia, tach, arrhythmias, nervousness, tremor Interactions T Risk of HTN crisis W/ MAOIs T effects W/BBs, sympathomimetics X effects W/TCAs -1- effect OF methyldopa, reserpine EMS Found in many OTC cough/cold pr >arations use sympathomimetics w/ caution, may T adverse effects OD May cause N/V, HTN, arrhythmias, and Szs symptomatic and supportive... 

Improper BP measurement Volume overload and pseudotolerance Volume retention from kidney diseaase Excess salt intake Inadequate diuretic therapy Drug induced or other causes Non-adherence to therapy Doses too low Inappropriate combinations Non-steroidal anti-inflammatory drugs Cocaine and other iflicit drugs Sympathomimetics (decongestants, anorectics)... 

Some drugs with sympathomimetic activity, including certain decongestants and cough syrups, should be avoided because they may precipitate a hypertensive crisis (Table 2-5). However, pure an-tihistaminic drugs, such as diphenhydramine, and pure expectorants without dextromethorphan, such as guaifenesin, are permissible. 

There are major differences in receptor types predominantly expressed in the various vascular beds (Table 9-4). The skin vessels have predominantly receptors and constrict in response to epinephrine and norepinephrine, as do the splanchnic vessels. Vessels in skeletal muscle may constrict or dilate depending on whether a or 13 receptors are activated. The blood vessels of the nasal mucosa express a, receptors, and local vasoconstriction induced by sympathomimetics explains their decongestant action (see Therapeutic Uses of Sympathomimetic Drugs). 

Phenylephrine is an effective mydriatic agent frequently used to facilitate examination of the retina. It is also a useful decongestant for minor allergic hyperemia and itching of the conjunctival membranes. Sympathomimetics administered as ophthalmic drops are also useful in localizing the lesion in Horner s syndrome. (See An Application of Basic Pharmacology to a Clinical Problem.)... 

Clemastine, 1.34 mg every 12 hours Tavist Allergy have minimal anticholinergic effects and are therefore associated with a lower incidence of sedation. Occasionally, symptoms unrelieved by the antihistamine respond to the addition of a sympathomimetic decongestant. OTC sale of products containing pseudoephedrine is restricted (see comments under Decongestants, systemic). 

D-Methamphetamine, the AZ-methyl derivative of amphetamine, was first synthesized in 1919. Methamphetamine is available in the d- and l-forms. The D-form has reportedly greater central stimulant activity than the L-isomer, which has greater peripheral sympathomimetic activity. The D-form is the commonly abused form while the L-isomer is typically found in nonprescription inhalers as a decongestant. 

Synephrine is a sympathomimetic agent with mainly direct effects on a-adren-ergic receptors. It has been used to treat hypotension and also as an ocular decongestant (389). It occurs in tangerines (Table II) in concentrations high enough to be physiologically active (119). 

Nasal Decongestants for Systemic Use Sympathomimetics (pseudoephedrine, phenylpropanolamine, phenylephrine) and structural analogues (epinephrine, ephedrine)... 

Decongestants and Antiallergics Sympathomimetics Used as Decongestants (naphazoline, tetryzoline, xylomethazoline, tramazoline)... 

SYMPATHOMIMETICS CYTOTOXICS -PROCARBAZINE Co-administration of ephedrine, metaraminol, methylphenidate, phenylephrine or pseudoephedrine (including nasal and ophthalmic solutions) with procarbazine may cause a prolongation and t intensity of the cardiac stimulant effects and effects on BP, which may lead to headache, arrhythmias, hypertensive or hyperpyretic crisis The metabolism of sympathomimetics is impaired due to an inhibition of MAO It is recommended that sympathomimetics not be administered during and within 14 days of stopping procarbazine. Do not use any OTC nasal decongestants (sprays or oral preparations) or asthma relief agents without consulting the pharmacist/doctor... 

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