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Methotrexate is a folic acid antagonist derived from aminopterin. It inhibits dihydrofolate reductase, the enzyme required in the pathway supplying methyl donor groups for DNA, RNA and protein synthesis. Methotrexate has been used for the treatment of diseases characterised by inflammation or cellular proliferation. In 1985 the first randomised, placebo-controlled trials were published that demonstrated the short-term efficacy of low-dose weekly methotrexate in rheumatoid arthritis (RA). Methotrexate is now the most widely used disease-modifying antirheumatoid drug (DMARD) in the developed world. It was first used in the treatment of psoriatic arthritis (PsA) in 1951, and has been shown to be of clinical benefit in this condition. However, methotrexate toxicity remains an important issue when considering its use, and is one of the main reasons for discontinuation. The most common adverse effects are gastrointestinal, such as anorexia, nausea, stomatitis and diarrhoea. CNS toxicity incl...

Therapeutic Class Calcium Channel Blocker Cardiovascular Agent Dihydropyridine Mechanism of Action Amlodipine besylate is a long-acting dihydropyridine calcium channel blocker that exerts its effect by blocking the transmembrane influx of calcium ions into cardiac and vascular smooth muscles. It also reduces peripheral vascular resistance and lowers blood pressure by causing a direct vasodilation in the peripheral arteries of the vascular smooth muscle. Its therapeutic effect on vasospastic angina is through inhibition of coronary spasm . Pharmacokinetics about 30 h to 50 h Hepatic Oral: time to peak concentration, 6 h to 12 h Protein binding: approximately 93% Renal: 60% as metabolites, 10% unchanged Bioavailability: 64% to 90% Impaired hepatic function: 56 h Effect of food: bioavailability not altered Patient Advice Patient should avoid activities requiring coordination until drug effects are realized, as drug may cause dizziness. This drug may cause palpitations, peripheral edema, f...