Type Sympathomimetic (directly acting) Drugs Norepinephrine Epinephrine lsoproterenol Sympathomimetic (indirectly acting) Dobutamine Salbutamol Salmeterol Terbutaline Clenbuterol Ritodrine Phenylephrine Methoxamine Clonidine Tyramine Amphetamine Ephedrine Summary of drugs that affect noradrenergic transmission Main action Uses/function α/βAgonist Not used clinically . Transmitter at postganglionic sympathetic neurons, and in CNS. Hormone of adrenal medulla α/βAgonist Asthma (emergency treatment), anaphylactic shock, cardiac arrest. Added to local anaesthetic solutions. Main hormone of adrenal medulla βAgonist (non-selective) Asthma (obsolete). Not an endogenous substance β1 Agonist (non-selective) Cardiogenic shock β2 Agonist Asthma, premature labour β2 Agonist Asthma β2 Agonist Asthma. Delay of parturition β2 Agonist 'Anabolic' action to increase muscle strength β2 Agonist Delay of parturition α1 Agonist Nasal decongestion αAgonist (non-selective) Nasal decongestion α2 Partial agonist Hypertension, migraine NA release No clinical uses. Present in various foods NA release, MAO inhibitor, uptake 1 Used as CNS stimulant in narcolepsy, also (paradoxically) inhibitor, CNS stimulant in hyperactive children, Appetite suppressant, Drug of abuse NA release, βagonist, weak CNS Nasal decongestion stimulant Adrenoceptor antagonists Phenoxybenzamine Phentolamine Prazosin Tamsulosin Yohimbine Propranolol Alprenolol Practolol Metoprolol Nebivolol Drugs affecting NA synthesis Drugs affecting NA release Butoxamine Labetalol Carvedilol α-Methyl- ptyrosine Carbidopa Methyldopa Reserpine Guanethidine Drugs affecting NA uptake Imipramine Cocaine αAntagonist (non-selective, irreversible) Uptake 1 inhibitor αAntagonist (non-selective), vasodilator α1 Antagonist α1 Antagonist ('uroselective') α2 Antagonist βAntagonist (non-selective) βAntagonist (non-selective) (partial agonist) β1 Antagonist β1 Antagonist β1 Antagonist Enhances nitric oxide-mediated transmission β2 Antagonist, weak α agonist α/βAntagonist α/βAntagonist Inhibits tyrosine hydroxylase Inhibits dopa decarboxylase False transmitter precursor Depletes NA stores by inhibiting vesicular uptake of NA Inhibits NA release Also causes NA depletion and can damage NA neurons irreversibly Blocks uptake 1 Also has atropine-like action Local anaesthetic; blocks uptake 1 CNS stimulant Phaeochromocytoma Rarely used Hypertension Prostatic hyperplasia Not used clinically Claimed to be aphrodisiac Angina, hypertension, cardiac dysrhythmias, anxiety tremor, glaucoma As propranolol Hypertension, angina, dysrhythmias Angina, hypertension, dysrhythmias Hypertension No clinical uses Hypertension in pregnancy Heart failure Occasionally used in phaeochromocytoma Used as adjunct to levodopaView drug information to prevent peripheral effects Hypertension in pregnancy Hypertension (obsolete) Hypertension (obsolete) Depression Rarely used local anaesthetic. Major drug of abuse