General information Rasagiline is a propargylamine that irreversibly and selectively inhibits monoamine oxidase type B and is 5–10 times more potent than selegiline. Its pharmacology, clinical pharmacology, clinical efficacy, and adverse reactions have been reviewed [ , ]. Rasagiline is rapidly absorbed from the gastrointestinal tract and readily enters the brain. Unlike selegiline, which is metabolized to amphetamines, rasagiline is metabolized to the non-amphetamine compound aminoindan.…

General information Rapacuronium, an aminosteroid non-depolarizing neuromuscular blocking agent with a rapid onset and a comparatively short duration of action [ , ], was withdrawn from the US market in March 2001 and subsequently worldwide. The manufacturers informed the FDA in an open letter about postmarketing reports of severe bronchospasm and some deaths of unknown origin associated with rapacuronium. The severity of the incidents recently reported…

General information The genera in the family of Ranunculaceae ( Table 1 ) include anemone, buttercup, columbine, hellebore, larkspur, marsh marigold, and pasque flower. Table 1 Genera of Ranunculaceae Aconitum (monkshood) Clematis (leather flower) Kumlienia (false buttercup) Actaea (baneberry) Consolida (knight’s-spur) Myosurus (mousetail) Adonis (pheasant’s eye) Coptis (gold thread) Nigella (nigella) Anemone (anemone) Delphinium (larkspur) Pulsatilla (pasque flower) Aquilegia (columbine) Enemion (false rue anemone) Ranunculus (buttercup)…

General information Ranolazine is a piperazine derivative approved for the treatment of chronic angina [ ]. It is thought to act by shifting myocardial energy metabolism away from free fatty acids and towards glucose as a substrate for production of adenosine triphosphate. It also has antidysrhythmic actions [ ]. Ranolazine is metabolized in the small intestine and liver to active metabolites, primarily by CYP3A4 and CYP3A5…

See also Histamine H 2 receptor antagonists General information Ranitidine is a histamine H 2 receptor antagonist. Compared with cimetidine, it inhibits hepatic metabolism of other substances only to a very slight extent and is not antiandrogenic. In most other respects it is similar to cimetidine. Drug studies Comparative studies Effervescent ranitidine 150 mg bd has been compared with as-needed calcium carbonate antacids 750 mg in…

Ranibizumab is a specific, affinity-mature, recombinant, humanized, antivascular endothelial growth factor-A (anti-VEGF-A) antibody fragment, which binds all isoforms of VEGF-A, rendering them inactive; it is effective in the treatment of age-related macular degeneration after intravitreal injection [ ]. Drug studies Comparative studies In a phase I/II randomized controlled trial 64 patients received either ranibizumab 0.3 or 0.5 mg (n = 53) or usual care (n =…

General information Ramoplanin was the first in a new class of antimicrobials to reach clinical trials [ ]. It is a glycolipodepsipeptide produced by the fermentation of Actinoplanes species [ ]. Ramoplanin blocks bacterial cell wall biosynthesis by interfering with peptidoglycan production. It inhibits the N-acetylglucosaminyltransferase-catalysed conversion of lipid intermediate I to lipid intermediate II, a step that occurs before the transglycosylation and transpeptidation reactions. Unlike…

See also Angiotensin-converting enzyme inhibitors General information Ramipril is an ACE inhibitor, a prodrug that is rapidly hydrolysed after absorption to its active metabolite ramiprilat. It has been used in patients with hypertension, heart failure, and myocardial infraction. Organs and systems Metabolism Hypoglycemia has been attributed to several drugs in a complicated sequence of effects [ ]. A 64-year-old man with type II diabetes, hypertension, and…

See also Cytotoxic and immunosuppressant drugs General information Raltitrexed is a specific inhibitor of thymidylate synthase. It is used to treat colorectal cancers. In about 1000 patients with advanced colorectal cancer, the dose-limiting toxic effects in phase 1 studies were gastrointestinal toxicity, myelosuppression, and weakness; adverse events during phase 2 and 3 studies were similar to those seen during phase 1 [ ]. In all comparative…

General information Raloxifene is a non-steroidal so-called “selective estrogen receptor modulator” (SERM), that is it binds to estrogen receptors, but this binding produces agonist effects at some sites and antagonist effects at others [ ]. It has estrogen agonist effects on bone and lipid metabolism but estrogen antagonist effects on the breast and endometrium; it is also claimed by its protagonists to have cardioprotective effects, perhaps…

See also Thorotrast General information Radioactive substances may be used in medicine as tracers, the quantities used in this case being merely sufficient to enable them to be detected, or as therapeutic agents, in which case the quantities employed and the amount of radiation emitted may be considerable. Risks resulting from the radiation itself fall outside the scope of this volume. Radio-iodine is covered in a…

General information Three radioactive isotopes of iodine are currently used in clinical medicine: 1. 131 I has a radioactive half-life of 8 days and a high-energy emitter; it is used mainly in the therapy of hyperthyroidism and thyroid cancer. 2. 123 I has a radioactive half-life of 13 hours and has replaced 131 I for diagnostic purposes; however, for in vivo imaging meta-stable technetium-99 ( 99m…

General information Racecadotril (ecadotril, anorphan, (S)-aetophan), through its active metabolite thiorphan, is an inhibitor of the neutral endopeptidase known as enkephalinase, thereby increasing exposure to substrates of the enzyme, including enkephalins and atrial natriuretic peptide [ ]. Increased exposure to atrial natriuretic peptide has not proved beneficial in patients with cardiac failure [ ]. However, the antihypersecretory effect in the gut makes it useful in the…

See also Vaccines General information Rabies vaccine was for a long time prepared from infected brain tissue, and neurological complications were likely to occur in as many as one in 300 cases. A second-generation vaccine prepared from duck embryo tissue is better tolerated in this respect, and third-generation vaccines prepared in non-neural tissue cultures or in human diploid cell (HDC) vaccines with a progressive improvement in…

See also Proton pump inhibitors General information The benefit to harm balance of rabeprazole, a proton pump inhibitor, has been reviewed [ , ]. The overall rate of drug withdrawal because of adverse reactions was 3%. Common adverse reactions included diarrhea, headache, and rashes. General adverse effects and adverse reactions In short-term and long-term studies of up to 2 years, headache was the most important reported…

General information Quinupristin and dalfopristin are two semisynthetic pristinamycin derivatives that are given in combination parenterally. Each component has bacteriostatic activity against Gram-positive bacteria, including multidrug resistant bacilli [ , ]. Quinupristin + dalfopristin can be used to treat macrolide-resistant streptococci, staphylococcal infections after failure of conventional therapy, or vancomycin-resistant Enterococcus faecium (and probably Enterococcus raffinosus ), but not vancomycin-resistant Enterococcus faecalis , Enterococcus avium ,…

General information Quinine was originally extracted from the bark of the Cinchona tree (Peruvian bark or Jesuits’ bark) and was used to treat ague (i.e. fever), usually due to malaria. It fell out of fashion with the advent of other antimalarial drugs, but has once again become the drug of first choice for malaria originating in areas with multiresistant Plasmodium falciparum . To be effective, quinine…

General information Quinidine is a class I antidysrhythmic drug. Its actions, clinical use, interactions, and adverse effects and reactions have been reviewed [ ]. General adverse effects and adverse reactions Gastrointestinal symptoms, including anorexia, nausea, and vomiting, are common. Quinidine has a negative inotropic effect on the heart and can cause heart failure and hypotension. It prolongs the QRS complex and QT interval and can cause…

General information Quinfamide is a dichloroacetyl quinolol that has been used as an amebicide [ ]. It acts on the trophozoites of Entamoeba histolytica , making the trophozoite incapable of propagation. It is not active against amebic cysts. In doses of 100–1200 mg adverse reactions have been frequent but mild, mainly comprising headaches and nausea [ ]. You’re Reading a Preview Become a Clinical Tree membership…

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