Drug differences

The definition of a drug differs between dictionaries and among the various professional specialisms. A search of the internet elicited various definitions and a paraphrase of the most memorable is a compound can be defined as a drug if, when injected into a rodent, it yields a scientific publication . Although this is a memorable definition, for the purposes of this review, however, a drug is defined broadly as a compound that has properties that influence the health of an animal when ingested or administered to that animal. A brief look at current literature will quickly convince the reader that this is a definition which covers man-made and natural compounds that can be extracted from plant material and microbes and iised. ... 

The dosages of antipsychotic drugs differed markedly between the six sites studied (see Table 12.2). Of note, there were more than 50% of patients in China, Hong Kong, Taiwan, and Singapore taking less than 600 mg chlorpromazine-equivalents... 

Adverse reactions to drugs differ in both type and incidence in the pediatric population. Because of immature metabolic pathways, infants and children may have different metabolic patterns than adults. This at least partially explains why neonates require lower theophylline serum concentrations for the treatment of neonatal apnea and why the incidence of hepatotoxi-city following acetaminophen overdose is much lower in young children than in adults [44,45]. Antibiotic adverse effects unique to the pediatric population may... 

The enantiomers of this drug differ in their efficacy and activity, with (D)-penicilla-mine being the enantiomer required for pharmaceutical preparations. The (l)-enantiomer is toxic, and its absorption by the human body is more than the (D)-enantiomer. While both enantiomers of penicillamine are desulfhydrated by (r.)-cysteine desulfhydrase, only the (l)-isomer inhibits the action of this enzyme [2], The reported optical rotation values for (D)-penicillamine are ... 

Probucol, introduced relatively recently as an antihypercholesteremic drug, differs chemically from other drugs. Chemically, probucol is ort/io-di-tertbutyl substituted b -mercap-tophenol. The mechanism of action of probucol is unknown. Being a lipophilic compound, it is easily distributed into fatty tissue and, as a result, approximately 20% of its maximum concentration in the blood is still maintained for 6 months. 

Noncatecholamine adrenomimetic drugs differ from the basic catecholamine structure primarily by having substitutions on their benzene ring. 

While essentially all ACE inhibitors have a similar mechanism of action and therefore exhibit similar efficacy in the treatment of hypertension and congestive heart failure, these drugs differ slightly in their pharmacokinetic profiles. Enalapril, lisinopril, and quinapril are excreted primarily by the kidney, with minimal liver metabolism, while the other prodrug compounds are metabolized by the liver and renally excreted. Thus, in patients with renal insufficiency, the half-life of renally excreted ACE inhibitors is prolonged. In addition, patients with impaired liver func-... 

Although all alkylating agents can cause the kinds of genetic damage just discussed, individual drugs differ from one another in their electrophilic reactivity, the structure of their reactive intermediates, and their pharmacokinetic properties. These differences will be reflected in the spectrum of their antitumor activities and in the toxicities they produce in normal tissues. 

Distribution of the drug is conceptualized as accumulation into various body compartments (e.g., fat, aqueous, bone, brain, etc.). The extent to which drugs differ in their rate and degree of accumulation into various organs is related to the number of compartments into which they equilibrate. Even within one apparent compartment, such as blood, there may be more than one subcomponent for distribution, including the following ... 

The 3-receptor-blocking drugs differ in their relative affinities for and 32 receptors (Table 10-1). Some have a higher affinity for 3 than for 32 receptors, and this selectivity may have important clinical implications. Since none of the clinically available 3-receptor antagonists are absolutely specific for receptors, the selectivity is dose-related it tends to diminish at... 

An important class of orally active ACE inhibitors, directed against the active site of ACE, is now extensively used. Captopril and enalapril are examples of the many potent ACE inhibitors that are available. These drugs differ in their structure and pharmacokinetics, but in clinical use, they are interchangeable. ACE inhibitors decrease systemic vascular resistance without increasing heart rate, and they promote natriuresis. As described in Chapters 11 and 13, they are effective in the treatment of hypertension, decrease morbidity and mortality in heart failure and left ventricular dysfunction after myocardial infarction, and delay the progression of diabetic nephropathy. 

Fasciolicides sold in the UK are listed in Table 12.1. The availability of drugs differs between countries and trade names are often not the same. The most important fasciolicide is triclabendazole because of its excellent activity against young flukes, enabling one dose to... 

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