Sem 4 Drugs Flashcards
co-amoxiclav
Amoxicillin (B lactam antibiotic) + clavulanic acid (B lactamase inhibitor) used in aspiration pneumonia, RTIs UTIs. Amoxicillin inhibits formation of peptidoglycan cross links in bacterial cell wall. Clavulanic acid prevents survuval of B lactamase enzyme which is produced by bacteria. Side effects: vomiting diarrhoea rash.
Botulinum toxin
used to treat achalasia. Inhibits Ca dependant release of Ach from presunaptic neurons. Relaxes lower oesophageal sphincter. symptoms can reoccur in 6 months.
antacids
theyre Mg/aluminium salts, treat dyspepsia. Neutralise gastric acid inside duodenum. Side effects: Mg-laxative. Al-constipation. Contraindication for patients with renal insufficiency.
Omeprazole/lansoprazole/pantoprazole/Rabeprazole sodium
Proton pump inhibitor, used to treat gastritis, gastric ulcers and peptic ulcers. Blocks the action of H+K+ATPase pump permanently in gastric parietal cell by binding to its sulphydryl group. Given in encapsulated formulation to avoid breakdown by stomach acid.
Esomeprazole (nexium)
second generation PPI (S isomer) treats gastritis and ulcers. Blocks H+K+ATPase pump permanently in gastric parietal cells by binding to sulphydryl group. In encapsulated form.
Ranitidine/cimetidine
Histamine 2 receptor antagonist, treats gastritis and ulcers. Blocks H2 receptor on parietal cells in stomach.
H pylori triple therapy-standard
2 antibiotics and PPI. eg clarithromycin amoxicillin PPI - omeprazole (CAP) Metronidazole can be used instead of amoxicillin. Treats H pylori infection which can cause ulcers. clarythromycin inhibits translation suring bacterial DNA synth. Side effects: GI disturbance, headache, dry mouth. use metronidazole for patients allergic to penicillin. Rebound hypersecretion can occur after prolonged use of omeprazole due to ↑gastrin established during treatment period
H. Pylori modern Bismuth based regimens therapy
2 antibiotics and bismuth compound. CAB-clarithromycin, amoxixillin and ranitidine Bismuth Citrate. The H2 antagonist ranitidine combined with bismuth compound coat gastric mucosa and help reduce HCL secretion. SE: GI disturbances, headaches, dry mouth. Use metronidazole for patients allergic to penicillin. Rebound hypersecretion can occur after prolonged use of omeprazole due to ↑gastrin established during treatment period
omeprazole
PPI. Block the action of the H+,K+ -ATPase pump permanently in the gastric parietal cell by binding to its sulphydryl group.
In pancreatitis, the ampulla of Vater is blocked. This means that the secretions from the pancreatic duct and the bile duct cannot enter the duodenum. Reducing HCl secretion reduces the stimulation of S cells in the duodenum. This means that less secretin is released, therefore, less bicarbonate ions are secreted by the pancreas.
pancreatin
digestive enzymes usually produced by exocrine pancreas n(amylase lipase trypsin, used to treat chronic pancreatitis and CF. SE: soreness of perioral skin, buccal mucosa and perianal skin. GI disturbances. Soreness occurs if tablet is held in mouth or dosage is too high due to enzyme activity.
fluorouracil 5-FU
pyrimidine analog, thymidylate synthase inhibitor, anti metabolite. used to treat colorectal cancer. - Prevents pyrimidine from incorporating into DNA during ‘S’ phase.
-Drug is converted to a ‘fraudulent’ nucleotide called FDUMP and inhibits thymidylate synthase preventing the conversion of 2’-deoxyuridylate (DUMP) to 2’-deoxythymidylate (DTMP) resulting in ↓DNA synthesis = cell death.
SE: alopecia, immunosupression dec WBC, platlets, neutrophils so inc risk infection. GI problems-nausea. Diarrhoea. Stomatitis. Tired. Anaemia.
folinic acid (leucovorin)
Ca/Na folinate. Enhance effect of 5FU. Counteract cytotoxic drug methotrecate. inc tetrahydrofolate for 5FU to bind and inc stability of 5FU-thymidylate synthase complex which inc cytotoxicity. SE: pyrexia, insomnia, depression, agitation.
PEG interferon a2A
antiviral. used in chrinic Hep B, C and acute hep C.-Binds to cell surface receptors on virally infected cells and interferes with the viral mRNA translation.
- Proteins that interfere with viral replication and activate other immune cells.
- Given as injection. SE: slu, ocular effects, depression, thyroid dysfunction, osteoporosis. Can be pegylated to inc half life.
Ribavirin (+PEG)
antiviral. Chronic Hep C.- Inhibits viral RNA dependent RNA polymerase enzyme, therefore inhibiting viral replication.
-RNA mutagen, giving a defective HCV.
-Given as an oral tablet.
SE: conjunctivitis, rash, dec pulmonary function in people with respiratory disease.
insulin
Rapid-Acting (lispro)
Short-Acting (regular)
Intermediate-Acting (NPH)
Long-Acting (glargine/detemir)
Pre-mixed (short + intermediate)
Used in diabetes. RA – 3-5 hrs (covers meal with injection)
SA – 5-8 hrs (covers meals within 30-60 minutes)
IA – 18-24 hrs (half a day/full night, used with RA/SA)
LA – up to 24 hrs (full day with RA/SA)
Pre-mixed – taken 2/3 times a day before meals
side effects: - Hypoglycaemia
- Muscle wasting/pain at injection site
- Rarely allergic reaction
its short acting Velosulin is used in insulin pumps
metformin
Biguanide (insulin sensitisers)
- First line DRUG for Type II diabetes. - Activates AMP kinase which is involved in GLUT4 metabolism.
- ↓gluconeogenesis in liver
- ↑ peripheral glucose uptake (GLUT4)
side effects:- Anorexia
- Epigastric discomfort
- Diarrhoea
- Lactic acidosis in patients with severe hepatic/renal disease.
- First line TREATMENT is diet/exercise change.
- Does not cause weight gain.
Gliclazide (X-amide/x-azide)
Sulfonylureas (increased insulin secretion) in Type II diabetes. - Activates sulfonylurea receptors which inhibits ATP-sensitive K+ channels ↑intracellular K+ depolarisation and Ca2+ influx insulin release, Side effects: - Hypoglycaemia - Weight gain - GI disturbances - ↑ beta cell destruction?
rosiglitazone, pioglitazone
Thiazolidinediones
(insulin sensitisers) in type II diabetes. - Interaction with peroxisome proliferator-activated receptor-gamma (PPAR-gamma), mainly found on adipose cells. This increases adipogenesis and glucose uptake.
- May lower free fatty acids promoting glucose uptake by muscles.
- Lower blood glucose but do not return to normal.
Side effects:- Weight gain of 5-6kg
- Oedema
- Hypoglycaemia
- Redistribution of fat from central adiposity to peripherals.
sitgliptin (X-gliptin)
DDP-4 Inhibitors, in type II diabetes. The DPP-4 enzyme degrades incretins such as GLP-1, thus reducing insulin secretion. Hence DDP-4 inhibitors increase the action of incretins, thereby increasing insulin secretion and reducing glucagon secretion.
Side effects:- GI disturbances (N&V)
- Headache, drowsiness, dizziness
- Hypoglycaemia (rare, only in overdose
X-tide
GLP-1 Receptor Agonists in type II diabetes. Acts as a functional analog of GLP-1, thus increasing insulin and reducing glucagon secretion. side effects GI disturbance and pancreatitis.
X-gliflozin
SGLT2 Inhibitors in type II. Reduction of glucose reabsorption in the kidney, reducing blood glucose levels.
Inhibition of SGLT2 (Sodium/Glucose cotransporter in the proximal tubule), preventing glucose reabsorption, allowing glucose to be passed out in the urine. Risk UTIs.
Miglitol/acarbose/voglibose/deoxynojiriimycin
Alpha-glucosidase Inhibitors used in type II.Prevent digestion of carbohydrates into monosaccharides, preventing food from increasing blood glucose levels.
Competitive inhibitor of alpha-glucosidase enzymes found in the small intestinal brush border, slowing carbohydrate digestion, can cause - Flatulence and diarrhoea (bacterial digestion of carbohydrates,
mannitol
osmotic diuretic. used for - ↑ICP/cerebral oedema
- ↑intraocular pressure
- Act on parts of nephron freely permeable to water e.g. proximal tubule, descending limb and collecting duct.
- Inert substance which ↑osmolarity of the filtrate and reduces passive reabsorption of water.
side effects - Hypotension
- Thrombophlebitis (vein inflammation due to thrombus)
- fluid and electrolyte imbalance
furosemide/bumetanide
loop diuretic. used in oedema, resistant hypertention. - Act on thick ascending loop of Henle.
- Inhibit the Na+/Cl-/K+ transporter by attaching to the Cl- binding site.
- These ions can therefore not be reabsorbed, as a result a hypotonic renal medulla is not formed and water remains in collecting duct.
- Mg2+ and Ca2+ reabsorption is dependent upon the reabsorption of the other ions these are also lost in urine.
side effects:- mild GI disturbances
- pancreatitis
- hypotension
- electrolyte disturbance (e.g. hypokalaemia)
- ↑ potassium intake should be encouraged.
- Most powerful diuretic
bendroflumethiazide
thiazide diuretics. used in mild to mod heart failure, hypertension. - Act on distal convoluted tubule.
- Block Na+/Cl- symporter by attaching to Cl- site, hence preventing their reabsorption.
- Also ↑ reabsorption of Ca2+ by increasing activity of Na+/Ca2+ antiport.
- K+ and H+ are lost due to activation of RAAS.
side effects - mild GI disturbances
- postural hypotension
- altered plasma-lipid concentrations
- electrolyte disturbance (e.g. hypokalaemia)
inc potassium uptake is encouraged.
trimterene, amiloride
K+ sparing. used in oedema heart failure adjunct with loop/thiazide diuretics. - Act on collecting ducts and tubules.
- Inhibit Na+ reabsorption by blocking lumenal channels and ↓K+ excretion.
side effects: - Hyperkalaemia
- GI disturbance
- Kidney stones
spironolactone, eplerenone
Aldosterone Antagonists, K+ sparing. used in - oedema/ascites
- heart failure
- primary hyperaldosteronism
- Act on distal tubule/collecting duct.
- Compete with aldosterone for intracellular receptor. Interfering with Na+/K+ exchange, reduces K+ excretion and Na+ reabsorption, weakly increasing diuresis.
side effects- GI disturbance
- Hyperkalaemia
- Gynaecomastia
- Menstrual disorder
- In combination with a stronger diuretic to reduce K+ loss.
- Potentiates loop/thiazides.
- Monitor K+, especially if also on ACE inhibitors
finasteride/dutasteride
5α-reductase inhibitor
(finasteride is selective for type II, dutasteride for I and II) used in - BPH
- Male-pattern baldness
- Prevents metabolism of testosterone into dihydrotestosterone which is indicated in causing prostate enlargement.
side effects - Impotence
- ↓libido
- Ejaculation disorders
tamsulosin/alfuzosin/doxozosin
Alpha-1 blockers (Tamsulosin selective for alpha-1a subtype specific to bladder neck/prostate/urethra) used in- BPH - Kidney stones - Inhibit the alpha 1/1a receptors resulting in relaxation muscles of bladder neck = ↑ urinary flow and ↓pain. side effects - Drowsiness - (postural) hypotension - Syncope - Retrograde ejaculation
carbimazole/methimazole/propylthyiouracil PTU
Pro-drug for methimazole
Thyroid hormone inhibitor
Mild immunosuppressant
used in hyperthyroidism. - Prevents thyroid peroxidase from iodinating and coupling tyrosine, therefore reducing hormone production.
- PTU: reduces the conversion of T4 to T3 in the peripheral tissue
side effects: - Nausea
- Mild GI disturbance
- Taste disturbance
- RARELY neutropenia and agranulocytosis – doctor must be warned non-specific illness e.g. sore throat, ulcers develop.
Quickly reduces hormone production however takes 10-20 days for clinical benefit due to high half lives of existing T4/T3. Hence β-blocker can be used for rapid symptom control.
thiocynate ions
used in hyperthyroidism - Reduces iodide trapping by competitive inhibition of the Na+/I- symporter
iodide ions
used in hyperthyroidism. - Given in high concentrations
- Reduces thyroid function
radioiodine
used in hyperthyroidism - Absorbed by thyroid.
- Emits beta and gamma radiation.
- Beta radiation kills thyroid follicle cells
propanolol
Non-selective β-blocker used in - Hypertension
- Anxiety
- Blocks adrenaline and noradrenaline at β1 and β2 adrenergic receptors
side effects: - GI disturbance
- Bradycardia
- Heart failure
Crosses BBB therefore may have psychological effects e.g. vivid dreams, psychoses
levothyroxine
used in hypOthyroidism. - Synthetic hormone to replaces deficient T4
If in excess) hyperthyroid symptoms.
