Vasoconstrictive properties of sympathomimetic drugs are the basis of their widespread use as decongestants and possible source of adverse responses. Insufficiently substantiated practice of combining decongestants in some marketed preparations, such are those containing phenylephrine and lerimazoline, may affect the overall contractile activity, and thus their therapeutic utility. This study aimed to examine the interaction between lerimazoline and phenylephrine in isolated rat aortic rings, and also to assess the substrate of the obtained lerimazoline-induced attenuation of phenylephrine contraction. Namely, while lower concentrations of lerimazoline (10⁻⁶ M and especially 10⁻⁷ M) expectedly tended to potentiate the phenylephrine-induced contractions, lerimazoline in higher concentrations (10⁻⁴ M and above) unexpectedly and profoundly depleted the phenylephrine concentration-response curve. Suppression of NO with NO synthase (NOS) inhibitor N(w)-nitro-L-arginine methyl ester (L-NAME; 10⁻⁴ M) or NO scavanger OHB₁₂ (10⁻³ M), as well as non-specific inhibition of K⁺-channels with tetraethylammonium (TEA; 10⁻³ M), have reversed lerimazoline-induced relaxation of phenylephrine contractions, while cyclooxygenase inhibitor indomethacin (10⁻⁵ M) did not affect the interaction between two vasoconstrictors. At the receptor level, non-selective 5-HT receptor antagonist methiothepin reversed the attenuating effect of lerimazoline on phenylephrine contraction when applied at 3×10⁻⁷ and 10⁻⁶ M, but not at the highest concentration (10⁻⁴ M). Neither the 5-HT1D-receptor selective antagonist BRL 15572 (10⁻⁶ M) nor 5-HT₇ receptor selective antagonist SB 269970 (10⁻⁶ M) affected the lerimazoline-induced attenuation of phenylephrine activity. The mechanism of lerimazoline-induced suppression of phenylephrine contractions may involve potentiation of activity of NO and K⁺-channels and activation of some methiothepin-sensitive receptors, possibly of the 5-HT(2B) subtype.
Animals ; Aorta* ; Indomethacin ; Methiothepin ; Nasal Decongestants ; Nitric Oxide Synthase ; Phenylephrine* ; Prostaglandin-Endoperoxide Synthases ; Rats* ; Relaxation ; Serotonin ; Sympathomimetics ; Tetraethylammonium ; Vasoconstrictor Agents

No abstract available.
Basilar Artery* ; Rabbits* ; Vasoconstrictor Agents* ; Vasodilator Agents*

Hepatorenal Syndrome ; drug therapy ; Humans ; Vasoconstrictor Agents ; therapeutic use

Nasotracheal intubation is often the method of choice in oral or maxillofacial operations. During the insertion of endotracheal tube (ETT) through nostril, a considerable damage can be inflicted on the nasal mucosa by forcing ETT into the nasal cavity, and epistaxis may occur as a result of mucosal damage even when vasoconstrictors, a lubricated tube, and careful manipulation are employed. This study was conducted to observe whether balloon dilation technique(BDT) can help to minimize the expected problems during nasotracheal tube insertion and was to tried to get a data for further studies. In 30 patients in whom the nasotracheal tube was placed, smooth passage into the nasal cavity without using BDT occurred in 9 patients(30.0%). Of 21 patients(70.0%) who were come into the use of BDT when resistance to tube insertion due to anatomical structures of the nasal cavity was encountered, epistaxis was not developed. By the above results, The BDT appers to prevent epistaxis during nasotracheal tube insertion and to make an easy and smooth passage of the tube and then it suggest that the BDT should provide a basic data and an alternative to conventional techniques for a safe and atraumatic nasotracheal intubation.
Epistaxis ; Humans ; Intubation ; Nasal Cavity ; Nasal Mucosa ; Vasoconstrictor Agents

Hepatorenal Syndrome ; therapy ; Humans ; Liver Transplantation ; Vasoconstrictor Agents ; therapeutic use

BACKGROUND: Septic shock causes life threatening organ dysfunction needing vasopressor despite adequate fluid resuscitation. Numerous studies and meta-analysis have proven norepinephrine as the initial vasopressor of choice in septic shock with vasopressin as add-on. Although guidelines have established the goal monitoring response in septic shock, optimal approach in discontinuation of the vasopressors in the recovery phase of septic shock remains limited. METHODS: A systematic review and meta-analysis was performed on randomized controlled trials (RCTs) and nonrandomized studies comparing incidence of hypotension within 24 hours of discontinuing norepinephrine first versus vasopressin. Three reviewers independently selected studies, assessed their quality, and extracted the following data: the number and characteristics of patients enrolled, inclusion and exclusion criteria for each study, the description of interventions (discontinuing norepinephrine first versus discontinuing vasopressin first) and outcomes (incidence of hypotension within 24 hours). RESULTS: Seven retrospective cohort studies and one prospective randomized control trial were included. Compared with norepinephrine, risk of hypotension is higher when vasopressin is discontinued first among patients in the recovery phase of septic shock (RR 2.06; 95% CI [1.11,3.82]; I 2 91%). Results were consistent in the subgroup analysis after excluding abstract-only and poor-quality studies (RR 1.73; 95% CI [0.74, 4.03]; I 2 93%). There is no difference in ICU (RR 0.97; 95% CI [0.71, 1.32]; I 2 38%) and in-hospital mortality (RR 0.88; 95% CI [0.66, 1.16]; I 2 41%) between the two vasopressor weaning strategies. Finally ICU length of stay was reported on 5 studies with no significant difference between the two strategies. CONCLUSION: Based on the results, there is increased risk of hypotension when vasopressin is discontinued first versus norepinephrine.
Norepinephrine ; Shock, Septic ; AVP protein, human ; Vasopressins ; Vasoconstrictor Agents ; Neurophysins

The effect of intravenously administered vasoconstrictor (nor-epinephrine, ephedrine and posterior pituitary hormone) and vasodilator (papaverine, nicotinic acid and theophylline) drugs on the choroidal blood flow of rabbits was studied by the apparatus based on the principle of Grayson's internal calorimetry. Thermistors, as the sensing elements, were introduced into the suprachoroidal space of rabbits eye, and continuous determinations were performed up to 60 minutes after the administration. Papaverine(2mg/kg), theophylline (5mg/kg and 50mg/kg) and nicotinic acid (25mg/kg and 50mg/kg) produced significant increase in the blood flow, papaverine and theophylline being the most powerful. Among the vasoconstrictor drugs, posterior pituitary hormone produced profound and prolonged decrease in the blood flow, whereas nor-epinephrine and ephedrine increase the blood flow following transient decreases in the blood flow. The relationships between blood pressure, intraocular pressure and choroidal blood flow, and the suggestions in the therapeutic applications to human eye were discussed.
Blood Pressure ; Calorimetry ; Choroid* ; Ephedrine ; Humans ; Intraocular Pressure ; Niacin ; Papaverine ; Rabbits* ; Theophylline ; Vasoconstrictor Agents

Epinephrine is one of the most widely-used vasoconstrictors in dental treatment including endodontic microsurgery. However, the systemic safety of epinephrine has been in debate for many years because of its potential risk to cause cardiovascular complications. The purpose of this review was to assess the cardiovascular effect of epinephrine use in endodontic microsurgery. Endodontic microsurgery directly applies epinephrine into the bone cavity, and the amount is reported to be much larger than other dental surgeries. Moreover, when considering that systemic potency of intraosseous application is reported to be comparable to intravenous application, the systemic influence of epinephrine could be increased in endodontic microsurgery. Besides, pre-existing cardiovascular complications or drug interactions can enhance its systemic influence, resulting in increased susceptibility to cardiovascular complications. Although clinical studies have not reported significant complications for patients without severe systemic complications, many epinephrine-induced emergency cases are warning the cardiovascular risk related with pre-existing systemic disease or drug interactions. Epinephrine is a dose-sensitive drug, and its hypersensitivity reaction can be fatal to patients when it is related to cardiovascular complications. Therefore, clinicians should recognize the risk, and the usage of pre-operative patient evaluation, dose control and patient monitoring are required to ensure patient's safety during endodontic microsurgery.
Cardiovascular Diseases ; Drug Interactions ; Emergencies ; Epinephrine* ; Hemostasis ; Humans ; Hypersensitivity ; Microsurgery* ; Monitoring, Physiologic ; Vasoconstrictor Agents

Vasoconstrictors such as epinephrine or phenylephrine have been used as an adjunct to local anesthetics to prolong the duration of spinal anesthesia. Recently, clonidine, an areceptor agonist, has been proved to have analgesic effect and to prolong epidural and spinal anesthesia. We used 0.3mg of epinephrine, 75 ug and 150 ug of clonidine in spinal anesthesia with 12 mg of T-Cain respectively and compared hemodynamic and analgesic effects of each drug. Heart rate and blood pressure were checked before, during and after anesthesia. Sensory level was checked by pin-prick method and motor blockade was measured by Bromages scale. The results were as follows. 1) Heart rate changed little in the epinephrine group and decreased significantly in all other groups.2) Systolic blood pressure decreased significantly in all groups except the epinephrine group. Both 75 ug and 150 ug of clonidine caused a significant fall in diastolic pressure. 3) The onset time for sensory and motor blockade varied little among all groups. 4) Sensory blockade was significantly higher in the 150 ug of clonidine group than the control group. Time to achieve the maximum level of sensory blockade was significantly faster in control group than 150 ug of clonidine group. 5) The duration of sensory and motor blockade was significantly prolonged in epinephrine and clonidine group than control group. The results indicate that clonidine, when used as an adjunct to T-Cain spinal anesthesia, is as effective as epinephrine in prolongation of motor and sensory blockade.
Anesthesia ; Anesthesia, Spinal* ; Anesthetics, Local ; Blood Pressure ; Clonidine* ; Epinephrine* ; Heart Rate ; Hemodynamics ; Phenylephrine ; Vasoconstrictor Agents

Effects of various peripheral vasoconstrictors on isolated porcine basilar and posterior communicating arteries(BA and PCA) were investingated and effected of flunarizine on the contractile responses were compared with those of a vasodilator, nitroglycerin. KCl elicited dose-dependent contractions in BA and PCA. 50mM KCl-induced contraction was not affected by nitroglycerin but dose-dependently inhibited by nimodipin and flunarizine in both rings. Epinephrine produced contractile response of BA and PCA in a dose-dependent fashion, but norepinephrine or phenylephrine did not cause obvious contraction by itself. Norepinephrine and phenylephrine elicited dose-dependent contractions in both rings treated with 10 -6M propranolol and the epinephrine-induced contractions were potentiated by pretreatment with propranolol, 5-hydroxytryptamine and histamine contracted BA and PCA in a dose-dependent manner and the contraction of PCA was more prominent than that of BA. In PCA rings, 10(-6)M 5-hydroxytryptamine and 10 -6M orepinephrine-induced contractions were not changed by nitroglycerin but inhibited by flunarizine in a dose-dependent manner. Small doses of flunarizine inhibited gradually both drug-induced contractions and large doses(3.5 x 10(-6) and 10(-6)M) steeply inhibit ed the contractions. Then the slopes of inhibitory curves in both cases were biphasic. Above results suggest that responsibility of catecholamine in porcine brain artery is more prominent in alpha-adrenoceptors than in beta-adrenoceptors, and inhibitory effect of flunarizine on brain artery results from inhibition of calcium influx through stimulated receptor-operated calcium channel(ROC) and potential-operated calcium channel(POC) .
Arteries* ; Brain* ; Calcium ; Epinephrine ; Flunarizine* ; Histamine ; Nitroglycerin ; Norepinephrine ; Passive Cutaneous Anaphylaxis ; Phenylephrine ; Propranolol ; Serotonin ; Vasoconstrictor Agents