Sem 4 Drugs

bethdrysdale's version from 2015-05-17 20:37


Question Answer
What is the action of Omeprazole?Inhibition of H+/K+ ATPase on parietal cells irreversibly (lasts 72 hours) at a sulphydryl group
Which conditions indicate the prescription of Omeprazole?Peptic ulcers, GERD, Zollinger-Ellison syndrome, NSAID prescription, dyspepsia
What are the adverse effects of Omeprazole?Diarrhoea, headache and abdominal pain (low incidence) and possible increase of C.Dif infection (bad bad bad) and other GI infections
What are some examples of Antacids?Sodium Carbonate, Calcium Carbonate, Magnesium/Aluminium Hydroxide
Why are Magnesium and Aluminium Hydroxide taken together?Mg(OH)2 causes constipation, Al(OH)3 causes diarrhoea, together they maintain normal bowel function
Why is longterm use of antacids (Mg/Al hydroxides) unsuitable for patients with serious renal disorders?the metals are normally absorbed by the kidneys
What are some examples of H2 receptor antagonists?Cimetidine, Ranitidine, Nizatadine and Famotidine
What is the desired effect of using a H2 receptor antagonist?Reduced gastric acid secretion due to competitive inhibition of the H2 receptors, preventing stimulation of the acid secreting parietal cells by histamine from ECL cells.
Why should H2 receptor antagonists be avoided by patients on warfarin, phenytoin and theophylline?binds to cytochrome P450, meaning it has many contraindications
Which enzymes are found in Pancreatin?Trypsin, Amylase and Lipase
Which conditions are Pancreatins prescribed for?pancreatitis, cystic fibrosis, pancreatic cancer or absence of the pancreas
The enzymes in pancreatin are stored in dissolvable capsules - why?to protect the upper GI tract (mouth and oesophagus)
Why must pancreatins be taken close to meal times?otherwise they can cause rashes or soreness in other parts of the GI tract (particularly the mouth and anus)
What is Fluorouracil?also known as 5-FU, it is a cytotoxic pyrimidine analogue used in the treatment of cancer
What are the three main mechanisms of action of fluorouracil?binds with the folate cofactor to thymidylate synthase (TS) preventing the methylation of dUMP to dTMP and thus the formation of the thymine precursor. It can also be incorporated into RNA preventing translation by ribosomes, or even DNA itself preventing transcription and thus both leading to inhibition of peptide synthesis.
What are the adverse effects of Fluorouracil?Oral mucositis, nausea/vomiting, tumour lysis syndrome, hyperuricaemia, bone marrow suppression (myelosuppression), alopecia
What is the action of leucovorin (folinic acid) when taken with fluorouracil?Enhances the action of fluorouracil by becoming the folate cofactor, stabilising the binding of 5-FdUMP to TS
What is the action of Carbimazole?prevents coupling of the thyroid peroxidase enzyme and the iodinating of the tyrosine residues by preventing iodide oxidation (to iodine). Prevents formation of T3 and T4.
Is carbimazole used for treatment of hypo- or hyperthyroidism?Hyperthyroidism
What is methimazole?The active form of carbimazole, which is a prodrug. (methimazole is used to treat hyperthyroidism in the US appaz)
Why are patients advised to report any signs of infection if taking carbimazole?There is a risk of agranulocytosis and neutropenia, due to bone marrow suppression, so if a sign of infection presents, a blood count is taken in case this is a presentation of these adverse effects.
What is Levothyroxine?A substitute for thyroxine (T4) prescribed for for hypothyroidism
When and why is radioactive Iodine (radioactive sodium iodide) used (treatment, not imaging)?Used to "fix" hyperthyroidism by causing radioactive cytotoxicity of the cells of the thyroid. The thyroid is the only part of the body (other than the kidneys) to uptake large amounts of Iodine. Uses beta-radiation predominantly
What is the main complication of using Radioactive Iodine to treat hyperthyroidism?hypothyroidism
What is the mechanism of alpha-interferon?binds to interferon receptors (IFNAR1 and IFNAR2c) leading to upregulation and expression of MHC1 proteins, allowing for increased presentation of viral peptides
What is alpha-interferon indicated for?Chronic hepB/C, hairy cell leukaemia, AIDS-related Kaposi's sarcoma etc
What is finasteride indicated for?benign prostatic hyperplasia
What is the mechanism of action of finasteride?it is a 5-alpha-reductase (type II) inhibitor, preventing the conversion of testosterone to dihydrotestosterone, decreasing serum DHT by around 65-70%, and prostate DHT levels by 85-90%
What is a significant side effect of finasteride?erectile dysfunction
What is the mechanism of tamsulosin?it is an alpha1a-adrenergic receptor antagonist used in the symptomatic treatment of BPH
What are the main adverse effects of tamsulosin?retrograde ejaculation, severe hypotension