Labetalol (Normodyne , Trandate , fixed combination with hydrochlorothiazide Hydrochlorothiazide, abbreviated HCTZ, HCT, or HZT, is a popular diuretic drug of the thiazide class that acts by inhibiting the kidneys' ability to retain water. This reduces the volume of the blood, decreasing blood return to the heart and thus cardiac output and, by other mechanisms, is believed to lower peripheral vascular resistance : Normozyde ) is a mixed alpha/beta adrenergic antagonist, which is used to treat high blood pressure Hypertension or high blood pressure is a chronic medical condition in which the blood pressure in the arteries is elevated. It is the opposite of hypotension. It is classified as either primary (essential) or secondary. About 90-95% of cases are termed "primary hypertension", which refers to high blood pressure for which no medical cause .[1]
Chemistry
Labetalol has stereoisomers Stereoisomers are isomeric molecules that have the same molecular formula and sequence of bonded atoms , but which differ only in the three-dimensional orientations of their atoms in space. Structural isomers share the same molecular formula, but the bond connections and/or their order between different atoms/groups differs. In stereoisomers, the .[2] racemic In chemistry, a racemic mixture, or racemate, is one that has equal amounts of left- and right-handed enantiomers of a chiral molecule. The first known racemic mixture was "racemic acid," which Louis Pasteur found to be a mixture of the two enantiomeric isomers of tartaric acid mixture of four isomers In chemistry, isomers are compounds with the same molecular formula but different structural formulas. The word is derived from the Greek ισομερης, isomerès; isos = "equal", méros = "part". There are many different classes of isomers, like stereoisomers, enantiomers, geometrical isomers, et cetera . Isomers do not . Two of these isomers, the (S,S)- and (R,S)- forms A chiral molecule is a type of molecule that lacks an internal plane of symmetry and has a non-superimposable mirror image. The feature that is most often the cause of chirality in molecules is the presence of an asymmetric carbon atom are inactive. The third, the (S,R)-isomer, is a powerful α1 blocker. The fourth isomer, the (R,R)-isomer, is a mixed nonselective β blocker Beta blockers is a class of drugs used for various indications, but particularly for the management of cardiac arrhythmias, cardioprotection after myocardial infarction (heart attack), and hypertension. As beta adrenergic receptor antagonists, they diminish the effects of epinephrine (adrenaline) and other stress hormones. Invented by Sir James W and selective β2 agonist.
It works by blocking these adrenergic receptors The adrenergic receptors are a class of G protein-coupled receptors that are targets of the catecholamines, especially noradrenaline (norepinephrine) and adrenaline (epinephrine). Although dopamine is a catecholamine, its receptors are in a different category , which decreases peripheral vascular resistance without significantly altering heart rate Heart rate is the number of heartbeats per unit of time - typically expressed as beats per minute - which can vary as the body's need for oxygen changes, such as during exercise or sleep. The measurement of heart rate is used by medical professionals to assist in the diagnosis and tracking of medical conditions. It is also used by individuals, or cardiac output Cardiac output is the volume of blood being pumped by the heart, in particular by a Left or Right ventricle in the Time interval of one minute. CO may be measured in many ways, for example dm3/min (1 dm3 equals 1000 cm3 or 1 litre). Q is furthermore the combined sum of output from the right ventricle and the output from the left ventricle during . The β:α antagonism of Labetalol is approximately 3:1.[3] [4]
Indications
It has a particular indication in the treatment of pregnancy-induced hypertension Gestational hypertension or pregnancy-induced hypertension is defined as the development of new arterial hypertension in a pregnant woman after 20 weeks gestation which is commonly associated with pre-eclampsia Pre-eclampsia is a medical condition where hypertension arises in pregnancy (pregnancy-induced hypertension) in association with significant amounts of protein in the urine. Because pre-eclampsia refers to a set of symptoms rather than any causative factor, it is established that there are many different causes for the syndrome. It also appears . [5]
It is also used to treat chronic hypertension Hypertension or high blood pressure is a chronic medical condition in which the blood pressure in the arteries is elevated. It is the opposite of hypotension. It is classified as either primary (essential) or secondary. About 90-95% of cases are termed "primary hypertension", which refers to high blood pressure for which no medical cause of pheochromocytoma A phaeochromocytoma or pheochromocytoma, is a neuroendocrine tumor of the medulla of the adrenal glands (originating in the chromaffin cells), or extra-adrenal chromaffin tissue that failed to involute after birth and secretes excessive amounts of catecholamines, usually adrenaline (epinephrine) if in the adrenal gland and not extra-adrenal, and and hypertensive crisis A hypertensive emergency is severe hypertension with acute impairment of an organ system (especially the central nervous system, cardiovascular system and/or the renal system) and the possibility of irreversible organ-damage. In case of a hypertensive emergency, the blood pressure should be lowered aggressively over minutes to hours with an .[3]
Administration
Labetalol is available in 100, 200, and 300 mg tablets and intravenously Intravenous therapy or IV therapy is the giving of liquid substances directly into a vein. The word intravenous simply means "within a vein". Therapies administered intravenously are often called specialty pharmaceuticals. It is commonly referred to as a drip because many systems of administration employ a drip chamber, which prevents (only as Trandate ) in 5 mg/ml solution. Adults taking tablets usually start with 100 mg twice daily, with a maximum of 2.4 g/day. In cases of emergency dosage might be higher. IV doses are usually started at 20mg over 2 minutes. Additional doses of 40mg, then 80mg may be administered every ten minutes as needed. Additional 80mg doses can be given to a total maximum dose of 300 mg. Additionally, labetalol can be administered by IV infusion at a rate of 2mg/minute, with a maximum dose of 300mg.
Side effects
Side effects may include:
Drowsiness Somnolence is a state of near-sleep, a strong desire for sleep, or sleeping for unusually long periods (cf. hypersomnia). It has two distinct meanings, referring both to the usual state preceding falling asleep, and the chronic condition referring to being in that state independent of a circadian rhythm. The disorder characterized by the latter Fatigue Fatigue is a state of awareness. It can describe a range of afflictions, varying from a general state of lethargy to a specific work-induced burning sensation within one's muscles. It can be both physical and mental. Physical fatigue is the inability to continue functioning at the level of one's normal abilities. It is ubiquitous in everyday life, Weakness Muscle weakness, also known as muscle fatigue, refers to the inability to exert force with one's skeletal muscles. Weakness often follows muscle atrophy and a decrease in activity, such as after a long bout of bedrest as a result of an illness Difficulty sleeping Insomnia is a symptom that can accompany several sleep, medical and psychiatric disorders, characterized by persistent difficulty falling asleep and/or difficulty staying asleep. Insomnia is typically followed by functional impairment while awake Diminished sexual function
Scalp tingling which passes after time.
Drug eruption In medicine, a drug eruption is an adverse drug reaction of the skin. Most drug-induced cutaneous reactions are mild and disappear when the offending drug is withdrawn. Drugs can also cause hair and nail changes, affect the mucous membranes, or cause itching without outward skin changes similar to lichen planus Lichen planus is a chronic mucocutaneous disease that affects the skin and the oral mucosa, and presents itself in the form of papules, lesions or rashes. Lichen planus doesn't involve lichens; the name refers to the appearance of affected skin [6] A rare but potentially lethal side effect is respiratory distress .
Contraindications
Labetalol has relative contraindications for use in patients with asthma, congestive heart failure, any degree of heart block, bradycardia, or those in cardiogenic shock.
References
^ "Labetalol infusion for refractory hypertension causing severe hypotension and bradycardia: an issue of patient safety" . Patient Saf Surg 2 : 13. doi A digital object identifier is a character string used to uniquely identify an electronic document or other object. Metadata about the object is stored in association with the DOI name and this metadata may include a location, such as a URL, where the object can be found. The DOI for a document is permanent, whereas its location and other metadata :10.1186/1754-9493-2-13 . PMID A PMID is a unique number assigned to each PubMed citation of life sciences and biomedical scientific journal articles. The related Pubmed Central archive may additionally assign a separate number, a PMCID (PubMed Central Identifier), normally written with a PMC prefix 18505576 . PMC PubMed Central is a free digital database of full-text scientific literature in biomedical and life sciences. It grew from the online Entrez PubMed biomedical literature search system. PubMed Central was developed by the U.S. National Library of Medicine as an online archive of biomedical journal articles 2429901 . http://www.pssjournal.com/content/2//13 . ^ "The alpha- and beta-adrenoceptor blocking activities of labetalol and its RR-SR (50:50) stereoisomers" . Br. J. Pharmacol. 104 (4): 823–8. PMID A PMID is a unique number assigned to each PubMed citation of life sciences and biomedical scientific journal articles. The related Pubmed Central archive may additionally assign a separate number, a PMCID (PubMed Central Identifier), normally written with a PMC prefix 1687367 . ^ a b Basic and clinical pharmacology . New York: McGraw-Hill Medical. p. 170. ISBN The International Standard Book Number is a unique numeric commercial book identifier based upon the 9-digit Standard Book Numbering (SBN) code created by Gordon Foster, now Emeritus Professor of Statistics at Trinity College, Dublin, for the booksellers and stationers W.H. Smith and others in 1966 0-07-145153-6 .
^ Br J Clin Pharmacol 3 (5): 849–855. PMID A PMID is a unique number assigned to each PubMed citation of life sciences and biomedical scientific journal articles. The related Pubmed Central archive may additionally assign a separate number, a PMCID (PubMed Central Identifier), normally written with a PMC prefix PMC1428931 . ^ http://www.bnf.org/bnf/bnf/56/2488.htm?q=%22labetalol%22 ^ Dermatology . St. Louis: Mosby. p. 161. ISBN The International Standard Book Number is a unique numeric commercial book identifier based upon the 9-digit Standard Book Numbering (SBN) code created by Gordon Foster, now Emeritus Professor of Statistics at Trinity College, Dublin, for the booksellers and stationers W.H. Smith and others in 1966 1-4160-2999-0 .
Adrenergics
Receptor In biochemistry, a receptor is a protein molecule, embedded in either the plasma membrane or the cytoplasm of a cell, to which one or more specific kinds of signaling molecules may attach. A molecule which binds to a receptor is called a ligand, and may be a peptide (short protein) or other small molecule, such as a neurotransmitter, a hormone, a
Ligands In coordination chemistry, a ligand is an ion, or molecule that binds to a central metal-atom to form a coordination complex. The bonding between metal and ligand generally involves formal donation of one or more of the ligand's electron pairs. The metal-ligand bonding can range from covalent to more ionic. Furthermore, the metal-ligand bond order
α1 The alpha-1 adrenergic receptor is a G protein-coupled receptor (GPCR) associated with the Gq heterotrimeric G-protein. It consists of three highly homologous subtypes, including α1A-, α1B-, and α1D-adrenergic. Catecholamines like norepinephrine (noradrenaline) and epinephrine (adrenaline) signal through the α1-adrenergic receptor in the
Agonists : 5-FNE • 6-FNE 6-Fluoronorepinephrine is a selective α1- and α2-adrenergic receptor full agonist related to norepinephrine. It is the only selective full agonist for the α-adrenergic receptors known to date and has been used to study their function in scientific research. Infusion of 6-FNE into the locus coeruleus of rodents produces marked hyperactivity and • Amidephrine Categories: Drugs not assigned an ATC code | Alpha-adrenergic agonists | Amines | Sulfonamides | Phenethylamines | • Anisodamine Anisodamine, also known as 7β-hydroxyhyoscyamine, is an alpha-adrenergic agonist • Anisodine • Cirazoline Cirazoline is a nonselective agonist of the alpha-1 adrenergic receptor , and an antagonist to the alpha-2 adrenergic receptor. It is believed that this combination of properties could make cirazoline an effective effective vasoconstricting agent • Dipivefrine Dipivefrine is a prodrug of epinephrine used to treat glaucoma. It is available as ophthalmic solution. It causes vasoconstriction, decreased aqueous humor production, and decreases intraoccular pressure. It is converted to epinephrine upon penetration of the cornea • Dopamine Dopamine is a catecholamine neurotransmitter that occurs in a wide variety of animals, including both vertebrates and invertebrates. In the brain, this phenethylamine functions as a neurotransmitter, activating the five types of dopamine receptors—D1, D2, D3, D4, and D5—and their variants. Dopamine is produced in several areas of the brain, • Ephedrine Ephedrine is a sympathomimetic amine commonly used as a stimulant, appetite suppressant, concentration aid, decongestant, and to treat hypotension associated with anaesthesia • Epinephrine Epinephrine is a hormone and neurotransmitter.. It increases heart rate, contracts blood vessels, dilates air passages and participates in the fight-or-flight response of the sympathetic nervous system. Chemically, epinephrine is a catecholamine, a monoamine produced only by the adrenal glands from the amino acids phenylalanine and tyrosine (Adrenaline) • Etilefrine Etilefrine, (2-ethylamino-1~ ethanol, is a sympathomimetic amine of the 3-hydroxy- phenylethanolamine series used in treating orthostatic hypotension of neurological, cardiovascular, endocrine or metabolic origin. Intravenous infusion of this compound increases cardiac output, stroke volume, venous return and blood pressure in man and experimental • Ethylnorepinephrine Ethylnorepinephrine , also known as butanefrine, is a sympathomimetic and bronchodilator related to norepinephrine • Indanidine Long acting β2-agonists : Arformoterol · Bambuterol · Clenbuterol · Formoterol · Salmeterol • Levonordefrin Levonordefrin , also known as α-Methylnorepinephrine (α-Me-NE), is a drug used as a topical nasal decongestant and vasoconstrictor in dentistry. It is also a metabolite of the antihypertensive drug methyldopa, and plays a crucial role in its pharmacology and therapeutic benefits • Metaraminol Metaraminol is a potent sympathomimetic amine used in the prevention and treatment of hypotension, particularly as a complication of anesthesia. It is an α1-adrenergic receptor agonist with some β effect • Methoxamine Methoxamine is an α1-adrenergic receptor agonist, similar in structure to phenylephrine and 2,5-DMA. It induces vasoconstriction of skin and splanchnic blood vessels, thereby increasing peripheral vascular resistance and raising mean arterial blood pressure. Because of its hypertensive effects, it may evoke a compensatory reflex bradycardia via • Methyldopa Methyldopa is a psychoactive drug used as a sympatholytic or antihypertensive. Its use is now deprecated following introduction of alternative safer classes of agents. However, it continues to have a role in otherwise difficult to treat hypertension and gestational hypertension (also known as pregnancy-induced hypertension (PIH)) • Midodrine Midodrine hydrochloride forms an active metabolite, desglyMidodrine, that is an alpha1-agonist, and exerts its actions via activation of the alpha-adrenergic receptors of the arteriolar and venous vasculature, producing an increase in vascular tone and elevation of blood pressure. DesglyMidodrine does not stimulate cardiac beta-adrenergic • Naphazoline Naphazoline is the common name for 2-(1-naphthylmethyl)-2-imidazoline hydrochloride. It is a sympathomimetic agent with marked alpha adrenergic activity. It is a vasoconstrictor with a rapid action in reducing swelling when applied to mucous membrane. It acts on alpha-receptors in the arterioles of the conjunctiva to produce constriction, • Norepinephrine Norepinephrine (abbreviated norepi or NE) or noradrenaline (BAN) (abbreviated NA or NAd) is a catecholamine with multiple roles including as a hormone and a neurotransmitter (Noradrenaline) • Octopamine • Oxymetazoline • Phenylephrine • Phenylpropanolamine • Pseudoephedrine • Synephrine • Tetrahydrozoline
Antagonists : Abanoquil • Adimolol • Ajmalicine • Alfuzosin • Amosulalol • Arotinolol • Atiprosin • Benoxathian • Buflomedil • Bunazosin • Carvedilol • CI-926 • Corynanthine • Dapiprazole • DL-017 • Domesticine • Doxazosin • Eugenodilol • Fenspiride • GYKI-12,743 • GYKI-16,084 • Indoramin • Ketanserin • L-765,314 • Labetalol • Mephendioxan • Metazosin • Monatepil • Moxisylyte (Thymoxamine) • Naftopidil • Nantenine • Neldazosin • Nicergoline • Niguldipine • Pelanserin • Phendioxan • Phenoxybenzamine • Phentolamine • Piperoxan • Prazosin • Quinazosin • Ritanserin • RS-97,078 • SGB-1,534 • Silodosin • SL-89.0591 • Spiperone • Talipexole • Tamsulosin • Terazosin • Tibalosin • Tiodazosin • Tipentosin • Tolazoline • Trimazosin • Upidosin • Urapidil • Zolertine
* Note that many TCAs , TeCAs , antipsychotics , ergolines , and some piperazines like buspirone , trazodone , nefazodone , etoperidone , and mepiprazole all antagonize α1 -adrenergic receptors as well, which contributes to their side effects such as orthostatic hypotension .
α2
Agonists : (R)-3-Nitrobiphenyline • 4-NEMD • 6-FNE • Amitraz • Apraclonidine • Brimonidine • Clonidine • Detomidine • Dexmedetomidine • Dihydroergotamine • Dipivefrine • Dopamine • Ephedrine • Ergotamine • Epinephrine (Adrenaline) • Esproquin • Etilefrine • Ethylnorepinephrine • Guanabenz • Guanfacine • Guanoxabenz • Levonordefrin • Lofexidine • Medetomidine • Methyldopa • Mivazerol • Naphazoline • Norepinephrine (Noradrenaline) • Phenylpropanolamine • Piperoxan • Pseudoephedrine • Rilmenidine • Romifidine • Talipexole • Tetrahydrozoline • Tizanidine • Tolonidine • Urapidil • Xylazine • Xylometazoline
Antagonists : 1-PP • Adimolol • Atipamezole • BRL-44408 • Buflomedil • Cirazoline • Efaroxan • Esmirtazapine • Fluparoxan • GYKI-12,743 • GYKI-16,084 • Idazoxan • Mianserin • Mirtazapine • MK-912 • NAN-190 • Olanzapine • Phentolamine • Phenoxybenzamine • Piperoxan • Piribedil • Rauwolscine • Rotigotine • SB-269,970 • Setiptiline • Spiroxatrine • Sunepitron • Tolazoline • Yohimbine
* Note that many atypical antipsychotics and azapirones like buspirone and gepirone (via metabolite 1-PP ) antagonize α2 -adrenergic receptors as well.
β
Agonists : 2-FNE • 5-FNE • Amibegron • Arbutamine • Arformoterol • Arotinolol • BAAM • Bambuterol • Befunolol • Bitolterol • Broxaterol • Buphenine • Carbuterol • Cimaterol • Clenbuterol • Denopamine • Deterenol • Dipivefrine • Dobutamine • Dopamine • Dopexamine • Ephedrine • Epinephrine (Adrenaline) • Etafedrine • Etilefrine • Ethylnorepinephrine • Fenoterol • Formoterol • Hexoprenaline • Higenamine • Indacaterol • Isoetarine • Isoprenaline (Isoproterenol) • Isoxsuprine • Labetalol • Levonordefrin • Levosalbutamol • Mabuterol • Methoxyphenamine • Methyldopa • N -Isopropyloctopamine • Norepinephrine (Noradrenaline) • Orciprenaline • Oxyfedrine • Phenylpropanolamine • Pirbuterol • Prenalterol • Ractopamine • Procaterol • Pseudoephedrine • Reproterol • Rimiterol • Ritodrine • Salbutamol (Albuterol) • Salmeterol • Solabegron • Terbutaline • Tretoquinol • Tulobuterol • Xamoterol • Zilpaterol • Zinterol
Antagonists : Acebutolol • Adaprolol • Adimolol • Afurolol • Alprenolol • Alprenoxime • Amosulalol • Ancarolol • Arnolol • Arotinolol • Atenolol • Befunolol • Betaxolol • Bevantolol • Bisoprolol • Bopindolol • Bormetolol • Bornaprolol • Brefonalol • Bucindolol • Bucumolol • Bufetolol • Buftiralol • Bufuralol • Bunitrolol • Bunolol • Bupranolol • Burocrolol • Butaxamine • Butidrine • Butofilolol • Capsinolol • Carazolol • Carpindolol • Carteolol • Carvedilol • Celiprolol • Cetamolol • Cicloprolol • Cinamolol • Cloranolol • Cyanopindolol • Dalbraminol • Dexpropranolol • Diacetolol • Dichloroisoprenaline • Dihydroalprenolol • Dilevalol • Diprafenone • Draquinolol • Dropranolol • Ecastolol • Epanolol • Ericolol • Ersentilide • Esatenolol • Esmolol • Esprolol •Eugenodilol • Exaprolol • Falintolol • Flestolol • Flusoxolol • Hydroxycarteolol • Hydroxytertatolol • ICI-118,551 • Idropranolol • Indenolol • Indopanolol • Iodocyanopindolol • Iprocrolol • Isoxaprolol • Isamoltane • Labetalol • Landiolol • Levobetaxolol • Levobunolol • Levocicloprolol • Levomoprolol • Medroxalol • Mepindolol • Metalol • Metipranolol • Metoprolol • Moprolol • Nadolol • Nadoxolol • Nafetolol • Nebivolol • Neraminol • Nifenalol • Nipradilol • Oberadilol • Oxprenolol • Pacrinolol • Pafenolol • Pamatolol • Pargolol • Parodilol • Penbutolol • Penirolol • PhQA-33 • Pindolol • Pirepolol • Practolol • Primidolol • Procinolol • Pronethalol • Propafenone • Propranolol • Ridazolol • Ronactolol • Soquinolol • Sotalol • Spirendolol • SR 59230A • Sulfinalol • TA-2005 • Talinolol • Tazolol • Teoprolol • Tertatolol • Terthianolol • Tienoxolol • Tilisolol • Timolol • Tiprenolol • Tolamolol • Toliprolol • Tribendilol • Trigevolol • Xibenolol • Xipranolol
Reuptake
Inhibitors
Releasing
Agents
Morpholines : Fenbutrazate • Morazone • Phendimetrazine • Phenmetrazine ; Oxazolines : 4-Methylaminorex • Aminorex • Clominorex • Cyclazodone • Fenozolone • Fluminorex • Pemoline • Thozalinone ; Phenethylamines (also Amphetamines , Cathinones , Phentermines , etc): 2-OH-PEA • 4-CAB • 4-FA • 4-FMA • 4-MA • 4-MMA • Alfetamine • Amfecloral • Amfepentorex • Amfepramone • Amphetamine (Dextroamphetamine , Levoamphetamine ) • Amphetaminil • β-Me-PEA • BDB • Benzphetamine • BOH • Buphedrone • Butylone • Cathine • Cathinone • Clobenzorex • Clortermine • D-Deprenyl • Dimethylamphetamine • Dimethylcathinone (Dimethylpropion, Metamfepramone) • DMA • DMMA • EBDB • Ephedrine • Ethcathinone • Ethylamphetamine • Ethylone • Fenethylline • Fenproporex • Flephedrone • Fludorex • Furfenorex • Hordenine • IAP • IMP • L-Deprenyl (Selegiline) • Lisdexamfetamine • Lophophine • MBDB • MDA (Tenamfetamine) • MDEA • MDMA • MDMPEA • MDOH • MDPEA • Mefenorex • Mephedrone • Mephentermine • Methamphetamine (Dextromethamphetamine , Levomethamphetamine ) • Methcathinone • Methedrone • Methylone • NAP • Ortetamine • Paredrine • pBA • pCA • Pentorex (Phenpentermine) • Phenethylamine • Pholedrine • Phenpromethamine • Phentermine • Phenylpropanolamine • pIA • Prenylamine • Propylamphetamine • Pseudoephedrine • Tiflorex • Tyramine • Xylopropamine • Zylofuramine ; Piperazines : 2C-B-BZP • BZP • MBZP • mCPP • MDBZP • MeOPP • pFPP ; Others : 2-Amino-1,2-dihydronaphthalene • 2-Aminoindane • 2-Aminotetralin • 2-Benzylpiperidine • 4-Benzylpiperidine • 5-IAI • Clofenciclan • Cyclopentamine • Cypenamine • Cyprodenate • Feprosidnine • Gilutensin • Heptaminol • Hexacyclonate • Indanorex • Isometheptene • Methylhexanamine • Octodrine • Phthalimidopropiophenone • Propylhexedrine (Levopropylhexedrine ) • Tuaminoheptane
Enzyme
Inhibitors
Others
Categories: Beta blockers | Salicylamides | Alcohols
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