Respiratory and Cardiovascular Drug Actions
This chapter describes much of the basic respiratory and cardiovascular physiology that underlies the action of the drugs presented, with the goal of elucidating the relationship between basic physiology and the drug mechanism of action (Table 45-1). Some of the trade names of the medications mentioned in the text will be changing, but the generic names will remain the same. Not all pharmacological interventions for the respiratory and cardiovascular systems are covered. Certainly, no attempt has been made to describe the pharmacology of other systems or disease states. For further study, any of the texts listed in the reference section at the end of the chapter are highly recommended.
Table 45-1
Respiratory and Cardiovascular Drugs
Sympathetic neurotransmission | Adrenergic (sympathomimetic) drugs | Norepinephrine |
Epinephrine | ||
Isoproterenol | ||
Phenylephrine and metaraminol | ||
Ephedrine | ||
Amphetamine | ||
Beta2-receptor stimulants | ||
Alpha-adrenergic blocking drugs | Phentolamine | |
Phenoxybenzamine | ||
Prazosin, doxazosin, and terazosin | ||
Beta-adrenergic blocking drugs | Propranolol | |
Metoprolol and atenolol | ||
Sympatholytic drugs | Reserpine | |
Guanethidine | ||
Methyldopa and clonidine | ||
Parasympathetic neurotransmission | Cholinergic drugs | Acetylcholine |
Bethanecol | ||
Carbachol | ||
Pilocarpine | ||
Anticholinesterase drugs | Physostigmine | |
Neostigmine | ||
Edrophonium | ||
Donepezil, rivastigmine, and galantamine | ||
Cholinergic blocking drugs | Atropine | |
Ipratropium and tiotropium | ||
Homatropine and cyclopentolate | ||
Dicyclomine | ||
Trihexyphenidyl HCL and benztropine mesylate | ||
Trimethaphan and mecamylamine | ||
Special considerations | Adrenergic (sympathomimetic) drugs | Epinephrine |
Ephedrine | ||
Albuterol, metaproterenol, terbutaline, pirbuterol, formoterol, and salmeterol | ||
Anticholinergics | Ipratropium and tiotropium | |
Methylxanthines | Theophylline and aminophylline | |
Corticosteroids | Budesonide, flunisolide, fluticasone, and triamcinolone | |
Mediator inhibitors | Cromolyn sodium and nedocromil sodium | |
Antileukotrienes | Zileuton, zafirlukast, and montelukast | |
Mucolytics and expectorants | Acetylcysteine | |
Guaifenesin |
Sympathetic Neurotransmission
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This expression, cardiac output, is a common one, and it constitutes half of the blood pressure regulation equation: CO × TPR = BP, where CO is cardiac output, TPR is total peripheral resistance, and BP is blood pressure. TPR is determined by vasoconstriction or vasodilation in the arterioles. For example, vasoconstriction increases resistance; therefore TPR and BP go up.
Adrenergic (Sympathomimetic) Drugs
Norepinephrine
Beta2-Receptor Stimulants
As mentioned above, there are several drugs that act primarily at the beta2 smooth muscle receptor site, causing selective actions in the bronchioles and arterioles but not in the heart (Box 45-1). These drugs will produce a bronchodilation without increasing cardiac output. This particular lack of cardiovascular effect makes them safer than drugs like isoproterenol or ephedrine in treatment of bronchial asthma. This class of drugs is currently part of the mainstay of treatment for asthma and chronic obstructive pulmonary disease (COPD).