Clinical pharmacology and Therapeutics Flashcards

Question

Moxonidine

Answer 1

Moxonidine is a centrally acting antihypertensive drug, which works by stimulating imidazoline receptors in the brain. This stimulation results in reduced sympathetic outflow from the central nervous system, leading to decreased vascular resistance and lower blood pressure. It's mainly used for treating essential hypertension.

Answer 2

1- Methyldopa: used in the management of hypertension during pregnancy 2- Moxonidine: used in the management of essential hypertension when conventional antihypertensives have failed to control blood pressure 3- Clonidine: the antihypertensive effect is mediated through stimulating alpha-2 adrenoceptors in the vasomotor centre

Answer 3

Foods with a high glycaemic index (GI), such as white bread, causes a rapid spike in blood glucose levels, followed by a quick drop

Answer 4

Drugs affected by acetylator status - Isoniazid - Procainamide - Hydralazine - Dapsone - Sulfasalazine

Answer 5

Drugs exhibiting zero-order kinetics - Phenytoin - Salicylates (e.g. high-dose aspirin) - Heparin - Ethanol

Answer 6

Phase I reactions: oxidation, reduction, hydrolysis.

Answer 7

Phase 2 reactions: Conjugation.

Answer 8

Fludrocortisone

Answer 9

Dexamethasone Betamethasone

Answer 10

Rasburicase - a recombinant version of urate oxidase, an enzyme that metabolizes uric acid to allantoin

Answer 11

Uric acid > 475umol/l or 25% increase potassium > 6 mmol/l or 25% increase phosphate > 1.125mmol/l or 25% increase calcium < 1.75mmol/l or 25% decrease

Answer 12

- Increased serum creatinine (1.5 times upper limit of normal) - cardiac arrhythmia or sudden death - seizure

Answer 13

Local anesthetic toxicity can be treated with IV 20% lipid emulsion

Answer 14

antibiotics: ciprofloxacin, tetracycline, chloramphenicol, sulphonamides psychiatric drugs: lithium, benzodiazepines aspirin carbimazole methotrexate sulfonylureas cytotoxic drugs amiodarone

Answer 15

antibiotics: penicillins, cephalosporins, trimethoprim endocrine: glucocorticoids (avoid high doses), levothyroxine* epilepsy: sodium valproate, carbamazepine asthma: salbutamol, theophyllines psychiatric drugs: tricyclic antidepressants, antipsychotics** hypertension: beta-blockers, hydralazine anticoagulants: warfarin, heparin digoxin

Answer 16

Precipitating factors classically: hypokalaemia digoxin normally binds to the ATPase pump on the same site as potassium. Hypokalaemia → digoxin more easily bind to the ATPase pump → increased inhibitory effects increasing age renal failure myocardial ischaemia hypomagnesaemia, hypercalcaemia, hypernatraemia, acidosis hypoalbuminaemia hypothermia hypothyroidism drugs: amiodarone, quinidine, verapamil, diltiazem, spironolactone (competes for secretion in distal convoluted tubule therefore reduce excretion), ciclosporin. Also drugs which cause hypokalaemia e.g. thiazides and loop diuretics

Answer 17

HIV uses CD4 to enter cells

Answer 18

Features - generally unwell, lethargy, nausea & vomiting, anorexia, confusion, yellow-green vision - arrhythmias (e.g. AV block, bradycardia) - gynaecomastia Precipitating factors - classically: hypokalaemia digoxin normally binds to the ATPase pump on the same site as potassium. Hypokalaemia → digoxin binds more easily to the ATPase pump → increased inhibitory effects - increasing age - renal failure - myocardial ischaemia hypomagnesaemia, hypercalcaemia, hypernatraemia, acidosis - hypoalbuminaemia - hypothermia - hypothyroidism - drugs: amiodarone, quinidine, verapamil, diltiazem, spironolactone (competes for secretion in distal convoluted tubule therefore reduce excretion), ciclosporin. Also drugs which cause hypokalaemia e.g. thiazides and loop diuretics

Answer 19

Causes of gynaecomastia physiological: normal in puberty syndromes with androgen deficiency: Kallman's, Klinefelter's testicular failure: e.g. mumps liver disease testicular cancer e.g. seminoma secreting hCG ectopic tumour secretion hyperthyroidism haemodialysis drugs: see below Drug causes of gynaecomastia spironolactone (most common drug cause) cimetidine digoxin cannabis finasteride GnRH agonists e.g. goserelin, buserelin oestrogens, anabolic steroids Very rare drug causes of gynaecomastia tricyclics isoniazid calcium channel blockers heroin busulfan methyldopa

Answer 20

- It is caused by Nicotinic acid deficiency. - 3 Ds, Diarrhea, Dementia, Dermatitis

Answer 21

Lengthens QT interval 1- ciprofloxacin 2- amiodarone 3- tricyclic antidepressants 4- antipsychotics

Answer 22

Widened QRS or arrhythmia in tricyclic overdose - give IV bicarbonate

Answer 23

Hypocalcaemia: Trousseau's sign is more sensitive and specific than Chvostek's sign

Answer 24

Trastuzumab Trastuzumab (Herceptin) is a monoclonal antibody directed against the HER2/neu receptor. It is used mainly in metastatic breast cancer although some patients with early disease are now also given trastuzumab. Adverse effects flu-like symptoms and diarrhoea are common cardiotoxicity more common when anthracyclines have also been used an echo is usually performed before starting treatment

Answer 25

Amiloride selectively blocks the epithelial sodium transport channels

Answer 26

Amiloride blocks the epithelial sodium channel in the distal convoluted tubule weak diuretic, usually given with thiazides or loop diuretics as an alternative to potassium supplementation (remember that thiazides and loop diuretics often cause hypokalaemia) Aldosterone antagonists e.g. spironolactone acts in the cortical collecting duct indications ascites: patients with cirrhosis develop a secondary hyperaldosteronism. Relatively large doses such as 100 or 200mg are often used heart failure nephrotic syndrome Conn's syndrome

Answer 27

Features hyperventilation (centrally stimulates respiration) tinnitus lethargy sweating, pyrexia* nausea/vomiting hyperglycaemia and hypoglycaemia seizures coma Treatment general (ABC, charcoal) urinary alkalinization with intravenous sodium bicarbonate - enhances elimination of aspirin in the urine haemodialysis Indications for haemodialysis in salicylate overdose serum concentration > 700mg/L metabolic acidosis resistant to treatment acute renal failure pulmonary oedema seizures coma

Answer 28

- Measles, Mumps, Rubella (MMR) - Varicella - Yellow Fever

Answer 29

(TIPC) Cholera CVD103-HgR Influenza-intranasal Poliomyelitis-oral (OPV) Tuberculosis (BCG)

Answer 30

Drug metabolism phase I: oxidation, reduction, hydrolysis phase II: conjugation

Answer 31

Drugs affected by acetylator status isoniazid procainamide hydralazine dapsone sulfasalazine

Answer 32

Drugs exhibiting zero-order kinetics phenytoin salicylates (e.g. high-dose aspirin) heparin ethanol

Answer 33

Acrodermatitis: red, crusted lesions acral distribution peri-orificial perianal alopecia short stature hypogonadism hepatosplenomegaly geophagia (ingesting clay/soil) cognitive impairment

Answer 34

1 - increased risk of breast cancer increased by the addition of a progestogen. 2- increased risk of endometrial cancer Oestrogen by itself should not be given as HRT to women with a womb.reduced by the addition of a progestogen but not eliminated completely. 3- increased risk of venous thromboembolism increased by the addition of a progestogen. 4-increased risk of stroke. 5- increased risk of ischaemic heart disease if taken more than 10 years after menopause.

Answer 35

Rifampicin inhibits RNA synthesis

Answer 36

- Inhibit cell wall formation (beta-lactams) penicillins: binds transpeptidase blocking cross-linking of peptidoglycan cell walls cephalosporins - Inhibit protein synthesis: these antibiotics are bateriostatic aminoglycosides (cause misreading of mRNA) chloramphenicol macrolides (e.g. erythromycin) tetracyclines fusidic acid - Inhibit DNA synthesis quinolones (e.g. ciprofloxacin) metronidazole sulphonamides trimethoprim - Inhibit RNA synthesis rifampicin

Answer 37

Vincristine acts during the metaphase

Answer 38

Azathioprine is metabolised to the active compound mercaptopurine, a purine analogue that inhibits purine synthesis. A thiopurine methyltransferase (TPMT) test may be needed to look for individuals prone to azathioprine toxicity. Adverse effects include bone marrow depression consider a full blood count if infection/bleeding occurs nausea/vomiting pancreatitis increased risk of non-melanoma skin cancer A significant interaction may occur with allopurinol and hence lower doses of azathioprine should be used. Azathioprine is generally considered safe to use in pregnancy.

Answer 39

Calcium channel blockers * Headache * Flushing * Ankle oedema Verapamil also commonly causes constipation Beta-blockers * Bronchospasm (especially in asthmatics) * Fatigue * Cold peripheries * Sleep disturbances Nitrates * Headache * Postural hypotension * Tachycardia Nicorandil * Headache * Flushing * Anal ulceration

Answer 40

Beta-blockers, such as carvedilol, can interfere with sleep by blocking beta-receptors, which in turn can suppress melatonin production and disrupt the normal sleep cycle. This often results in symptoms like insomnia, difficulty falling asleep, and vivid dreams

Answer 41

- primary and secondary immunodeficiency - Idiopathic Thrombocytopenic Purpura - Myasthenia gravis - Guillain-Barre syndrome - Kawasaki disease - Toxic epidermal necrolysis - Pneumonitis induced by CMV following transplantation - Low serum IgG levels following haematopoietic stem cell transplant for malignancy - dermatomyositis - chronic inflammatory demyelinating polyradiculopathy

Answer 42

Causes of drug-induced photosensitivity 1- Thiazides 2- tetracyclines, sulphonamides, ciprofloxacin 3- amiodarone 4- NSAIDs e.g. piroxicam 5- Psoralens 6- sulphonylureas

Answer 43

Toxicity may be precipitated by: 1- dehydration 2- renal failure 3- drugs: diuretics (especially thiazides), ACE inhibitors/angiotensin II receptor blockers, NSAIDs, and metronidazole.

Answer 44

Amitriptyline can cause urinary retention

Answer 45

sildenafil (Viagra) This was the first phosphodiesterase type V inhibitor short-acting - usually taken 1 hour before sexual activity tadalafil (Cialis) longer acting than sildenafil, may be taken on a regular basis (e.g. once daily) vardenafil (Levitra)

Answer 46

<0.4 mmol/L or tetany, arrhythmias, or seizures intravenous magnesium replacement is commonly given. an example regime would be 40 mmol of magnesium sulphate over 24 hours. >0.4 mmol/l oral magnesium salts (10-20 mmol orally per day in divided doses) diarrhoea can occur with oral magnesium salts.

Answer 47

Metabolic acidosis with a high anion gap and high osmolar gap is seen in ethylene glycol poisoning. Fomepizole, an inhibitor of alcohol dehydrogenase, is now used first-line

Answer 48

Cyanide may be used in insecticides, photograph development and the production of certain metals. Cyanide inhibits the enzyme cytochrome c oxidase, resulting in cessation of the mitochondrial electron transfer chain. Presentation 'classical' features: brick-red skin, smell of bitter almonds acute: hypoxia, hypotension, headache, confusion chronic: ataxia, peripheral neuropathy, dermatitis Management supportive measures: 100% oxygen definitive: hydroxocobalamin (intravenously), also combination of amyl nitrite (inhaled), sodium nitrite (intravenously), and sodium thiosulfate (intravenously)

Answer 49

Causes Friedreich's ataxia, ataxic telangiectasia neoplastic: cerebellar haemangioma stroke alcohol multiple sclerosis hypothyroidism drugs: phenytoin, lead poisoning paraneoplastic e.g. secondary to lung cancer

Answer 50

Magnesium sulphate - monitor reflexes + respiratory rate

Answer 51

Most common causes procainamide hydralazine Less common causes isoniazid minocycline phenytoin

Answer 52

Isoniazid inhibits the P450 system

Answer 53

Methaemoglobinaemia Methaemoglobinaemia describes haemoglobin which has been oxidised from Fe2+ to Fe3+. This is normally regulated by NADH methaemoglobin reductase, which transfers electrons from NADH to methaemoglobin resulting in the reduction of methaemoglobin to haemoglobin. There is tissue hypoxia as Fe3+ cannot bind oxygen, and hence the oxidation dissociation curve is moved to the leftCongenital causes haemoglobin chain variants: HbM, HbH NADH methaemoglobin reductase deficiency Acquired causes drugs: sulphonamides, nitrates (including recreational nitrates e.g. amyl nitrite 'poppers'), dapsone, sodium nitroprusside, primaquine chemicals: aniline dyes

Answer 54

- Quinolones should generally be avoided in women who are pregnant or breastfeeding - Avoid in G6PD

Answer 55

Thiazide diuretics work by inhibiting sodium reabsorption at the beginning of the distal convoluted tubule (DCT) by blocking the thiazide-sensitive Na+-Clˆ’ symporter. -Common adverse effects dehydration postural hypotension hypokalaemia due to increased delivery of sodium to the distal part of the distal convoluted tubule → increased sodium reabsorption in exchange for potassium and hydrogen ions hyponatraemia hypercalcaemia the flip side of this is hypocalciuria, which may be useful in reducing the incidence of renal stones gout impaired glucose tolerance impotence Rare adverse effects thrombocytopaenia agranulocytosis photosensitivity rash pancreatitis

Answer 56

Atrial natriuretic peptide - powerful vasodilator

Answer 57

Prescribing methotrexate - methotrexate is a drug with a high potential for patient harm. It is therefore important that you are familiar with guidelines relating to its use methotrexate is taken weekly, rather than daily FBC, U&E and LFTs need to be regularly monitored. The Committee on Safety of Medicines recommend 'FBC and renal and LFTs before starting treatment and repeated weekly until therapy stabilised, thereafter patients should be monitored every 2-3 months' folic acid 5mg once weekly should be co-prescribed, taken more than 24 hours after methotrexate dose the starting dose of methotrexate is 7.5 mg weekly (source: BNF) only one strength of methotrexate tablet should be prescribed (usually 2.5 mg) Interactions avoid prescribing trimethoprim or co-trimoxazole concurrently - increases risk of marrow aplasia high-dose aspirin increases the risk of methotrexate toxicity secondary to reduced excretion Methotrexate toxicity the treatment of choice is folinic acid

Answer 58

The following drugs tend to cause a hepatocellular picture: paracetamol sodium valproate, phenytoin MAOIs halothane anti-tuberculosis: isoniazid, rifampicin, pyrazinamide statins alcohol amiodarone methyldopa nitrofurantoin The following drugs tend to cause cholestasis (+/- hepatitis): combined oral contraceptive pill antibiotics: flucloxacillin, co-amoxiclav, erythromycin* anabolic steroids, testosterones phenothiazines: chlorpromazine, prochlorperazine sulphonylureas fibrates rare reported causes: nifedipine Liver cirrhosis methotrexate methyldopa amiodarone

Answer 59

Oral labetalol is now first-line following the 2010 NICE guidelines. Nifedipine (e.g. if asthmatic) and hydralazine may also be used delivery of the baby is the most important and definitive management step. The timing depends on the individual clinical scenario

Answer 60

Phenytoin is well known to cause neurological side effects such as peripheral sensory neuropathy and cerebellar ataxia. Other side effects include: Gingival hypertrophy Lymphadenopathy Hypocalcaemia, and Hirsutism.

Answer 61

The drugs which can classically cause pulmonary fibrosis include: Cytotoxics: busulphan, bleomycin, methotrexate, cyclophosphamide, carmustine Antibiotics: e.g. nitrofurantoin Cardiac drugs: hydralazine, amiodarone, tocainide Opiates: e.g. heroin abuse Sulphasalazine

Clinical pharmacology and Therapeutics Flashcards

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