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See also Antihistamines General information Azelastine is a second-generation antihistamine, a phthalazinone compound with antiallergic and bronchodilator properties [ ]. It is available as a nasal spray and in oral form for the treatment of allergic rhinitis and asthma as well as dermatoses. It reduces rhinorrhea, sneezing, and nasal congestion. Azelastine is effective against exercise-induced asthma and allergen challenge in patients with extrinsic asthma. It can…

See also Tioguanine General information Azathioprine, 6-mercaptopurine, and 6-thioguanine are thiopurines. Azathioprine is a prodrug of mercaptopurine and thioguanine is an active metabolite. Thioguanine is covered in a separate monograph. Azathioprine, 6-(1-methyl-4-nitroimidazole-5-yl)-thiopurine, is converted non-enzymatically to mercaptopurine ( Figure 1 ) and subsequently to thioguanine nucleotides. It is therefore not unexpected for patients who have experienced adverse reactions to azathioprine to have similar reactions to the…

See also Non-steroidal anti-inflammatory drugs (NSAIDs) General information Azapropazone is structurally related to phenylbutazone and probably shares the same adverse effects: gastrotoxicity, skin reactions, headache, vertigo, edema, and renal impairment. A review of a very large series described azapropazone adverse effects in 1724 patients (18%), causing withdrawal in 3.7%. Surprisingly, however, there were no phenylbutazone-type blood dyscrasias [ ]. Azapropazone should be prescribed only for patients…

General information Azacitidine has been approved for the treatment of myelodysplastic syndrome. It inhibits DNA methyltransferase, resulting in hypomethylation of DNA and direct cytotoxicity in abnormal hemopoietic cells in the bone marrow. The recommended dosage is 75 mg/m 2 /day given subcutaneously for 7 days every 4 weeks [ ]. The absolute systemic availability after subcutaneous administration is about 89%. After intravenous and subcutaneous administration the…

General information Avoparcin is a glycopeptide antibiotic (see also teicoplanin and vancomycin), a large molecule that is produced by a variety of environmental micro-organisms, which may therefore contain genes that code for antimicrobial drug resistance. It is mostly active against Gram-positive bacteria, such as enterococci and staphylococci. You’re Reading a Preview Become a Clinical Tree membership for Full access and enjoy Unlimited articles Become membership If…

See also Anticholinergic drugs General information Atropine is an anticholinergic drug that is mainly used today in premedication and occasionally to treat bradycardia in the acute phase of myocardial infarction. Organs and systems Cardiovascular In a classic study, more than a generation ago, of patients given atropine sulfate intravenously as premedication in a total dose of 1 mg, dysrhythmias occurred in over one-third of the subjects,…

See also Neuromuscular blocking agents General information Atracurium is a muscle relaxant with approximately one-fifth the potency of pancuronium (initial doses of 0.3–0.6 mg/kg and maintenance doses of 0.2 mg/kg being commonly used), an onset of action of 1.2–4 minutes (depending on the dose and the investigator), a medium duration of effect similar to (or slightly longer than) vecuronium, a rapid spontaneous recovery (slightly longer than…

General information Atovaquone is a hydroxynaphthaquinone that is effective in the prevention and treatment of murine Pneumocystis jirovecii pneumonitis. It also has effects against Toxoplasma gondii and Plasmodium falciparum . Food increases its absorption. The maximum serum concentration is dose-dependent, but absorption is reduced at doses above 750 mg. The maximum concentration occurs after 4–6 hours, with a second peak 24–96 hours later, suggesting enterohepatic cycling.…

See also HMG coenzyme-A reductase inhibitors General information Atorvastatin is an HMG Co-A reductase inhibitor. Pooled data from 21 completed and 23 continuing trials representing 3000 patient-years have shown that constipation, flatulence, dyspepsia, abdominal pain, headache, and myalgia occur in 1–3% of patients. Under 2% of atorvastatin-treated patients discontinued treatment because of an adverse event [ ]. Serious events in this review amounted to one patient…

General information Atomoxetine is a non-stimulant noradrenaline reuptake inhibitor that is efficacious in the treatment of ADHD [ ]. Sudden deaths of children and adolescents taking Adderall XR® have led to the need to screen children for risks of heart defect before beginning this stimulant medication. The label for atomoxetine has been altered to include a boxed warning and additional warning statements regarding an increased risk…

See also Beta-adrenoceptor antagonists General information Although atenolol, a hydrophilic cardioselective beta-adrenoceptor antagonist with no partial agonist activity, is generally regarded as one of the safest beta-blockers, severe adverse effects are occasionally reported. These include profound hypotension after a single oral dose [ ], organic brain syndrome [ ], cholestasis [ ], and cutaneous vasculitis [ ]. Organs and systems You’re Reading a Preview Become a…

General information Atazanavir is an inhibitor of HIV protease. It is used once daily in a dose of 400 mg or in combination with ritonavir as atazanavir + ritonavir 300 + 100 mg/day [ ]. Organs and systems Metabolism In an analysis of a randomized comparison of atazanavir and nelfinavir in 467 patients cardiovascular risk modelling was used to estimate the impact of dyslipidemia [ ].…

See also Herbal medicines General information There are about 600 genera in the family of Asteraceae (formerly Compositae), including various types of asters (daisies), arnica, chamomile, goldeneye, marigold, snakeroot, tansy, thistle, and wormwood. Delayed hypersensitivity reactions to the Asteraceae (Compositae) can arise from sesquiterpene lactones. To detect contact allergy to sesquiterpene lactones, a mixture of lactones (alantolactone, costunolide, and dehydrocostus lactone) is used. However, Compositae contain…

See also Antihistamines General information Astemizole is a second-generation antihistamine that has been withdrawn from the market because of the association with life-threatening cardiac arrhythmias. Organs and systems You’re Reading a Preview Become a Clinical Tree membership for Full access and enjoy Unlimited articles Become membership If you are a member. Log in here

General information Asparaginase is an enzyme that acts by breaking down the amino acid L-asparagine to aspartic acid and ammonia. It interferes with the growth of malignant cells that cannot synthesize L-asparagine. Its action is reportedly specific for the G1 phase of the cell cycle. It is used mainly for the induction of remissions in acute lymphoblastic leukemia. Nomenclature Colaspase and crisantaspase are the British Approved…

Genera in the family of Asparagaceae ( Table 1 ) include asparagus, aspidistra, and hyacinth. Table 1 Genera of Asparagaceae Acanthocarpus (popcornflower) Drimiopsis (drimiopsis) Parsonsia (silkpod) Agave (century plants) Eriospermum (eriospermum) Peliosanthes (tropical lily of the valley) Albuca (slime lilies) Eustrephus (wombat berry) Polygonatum (King Solomon's-seal) Asparagus (asparagus) Fusifilum (fusifilum) Rohdea (sacred lily) Aspidistra (aspidistra) Hosta hosta Romnalda (romnalda) Bowiea (climbing onion) Hyacinthoides (hyacinth) Ruscus (broom)…

General information The Average Daily Requirement of ascorbic acid is 30 mg. The Population Reference Intake is 45 mg/day for adults. The Lowest Threshold Intake, for which considerable evidence exists, is 12 mg/day [ ]. These estimates have been supported by the relevant committee of the European Union. A communication from the US National Academy of Sciences, as part of the revision of US Dietary Reference…

See also Clusiaceae ; Herbal medicines General information Genera in the family of Asclepiadaceae ( Table 1 ) include milkweed and periploca. Many of them contain cardiac glycosides. Table 1 Genera of Asclepiadaceae Araujia (araujia) Asclepias (milkweed) Calotropis (calotropis) Cryptostegia (rubbervine) Cynanchum (swallow-wort) Funastrum (twinevine) Gonolobus (gonolobus) Hoya (hoya) Marsdenia (marsdenia) Matelea (milkvine) Metaplexis (metaplexis) Morrenia (morrenia) Xysmalobium You’re Reading a Preview Become a Clinical Tree…

General information Acesulfame Acesulfame is an artificial sweetener derived from aceto-acetic acid. It is used in a wide range of non-medicinal products [ ]. Aspartame Aspartame is a dipeptide that is used as an artificial sweetener. It is completely hydrolysed in the gastrointestinal tract to methanol, aspartic acid, and phenylalanine [ ]. Aspartame appears to be a safe sweetener, and despite numerous studies of its safety…