Describe the pharmacology of drugs used to manage acute or chronic cardiac failure, including: sympathomimetics, phosphodiesterase inhibitors, digoxin, diuretics, ACE inhibitors, nitrates and beta blockers
A guest post from an ex PEX chair :
Agatha Christie knew a lot about poisoning, probably as a result of working with a pathologist. (https://bookshop.theguardian.com/catalog/product/view/id/323440/). After reading this book, you would have to be brave to go into an English garden.
One of her garden poisons was foxglove, which made me think of digoxin. As did the recent death of Miles Vaughan Williams, who classified anti arrhythmics. So often we see digoxin toxicity in clinical practice. An old drug, but one that continues to be used, and is loved by examiners because it allows for candidates to demonstrate an understanding of many different facets of pharmacology.
TRUE/FALSE Digoxin is highly protein bound, hence the introduction of another highly protein bound drug is likely to precipitate toxicity
TRUE/FALSE Digoxin is primarily excreted renally, and frequently patients who are prescribed digoxin may have borderline or impaired renal function which may precipitate toxicity
TRUE/FALSE Overdosage of digoxin may be treated using Digibind (R) which is an example of an immunoglobulin which binds to digoxin to cease its therapeutic effect
TRUE/FALSE Hypokalaemia is frequently seen in digoxin toxicity, reflecting digoxin’s inhibition of the Na/Ca pump
TRUE/FALSE The bioavailability of digoxin is reasonably high (approx 70%) allowing for oral loading doses to be only slightly slower in reaching therapeutic effects compared with intravenous loading doses