1 Flashcards
Cytochrome P450 inducers
CRAP GPs Carbemazepines Rifampicin Alcohol Phenytoin Griseofulvin Phenobarbitone Sulphonylureas
Cytochrome P450 inhibitors
SICKFACES.COM Sodium valproate Isoniazid Cimetidine Ketoconazole Fluconazole Alcohol & Grapefruit juice Chloramphenicol Erythromycin Sulfonamides Ciprofloxacin Omeprazole Metronidazole
AODEVICES Allopurinol Omeprazole Disulfiram Erythromycin Valproate Isoniazid Ciprofloxacin Ethanol (acute) Sulphonamides
Steroids side effects
STEROIDS Stomach ulcers Thin skin oEdema Right and left heart failure Osteoporosis Infection (including Candida) Diabetes (commonly causes hyperglycaemia and uncommonly progresses to diabetes) Syndrome - cushing's
NSAID cautions and contraindications
NSAID No urine (i.e. renal failure) Systolic dysfunction (i.e. heart failure) Asthma Indigestion (any cause) Dyscrasia (clotting abnormality)
ACE-inhibitor main side effects (x2), how and an example
1) Dry cough through accumulation of bradykinin via reduced degradation by ACE
2) Hyperkalaemia through reduced aldosterone production and thus reduced potassium excretion in the kidneys
E.g. lisinopril
What electrolyte disturbance do loop and thiazide diuretics (inc bendroflumethiazide) cause?
Hypokalaemia
What electrolyte disturbance do aldosterone antagonists and ACE-inhibitors cause?
Hyperkalaemia
What drugs contribute to indigestion?
Ibuprofen inhibits prostaglandin synthesis needed for gastric mucosal protection from acid. It is therefore at risk of influencing inflammation and ulceration.
Oral steroids inhibit gastric epithelial renewal thus predisposing to ulceration.
Drugs responsible for renal failure
Ibuprofen inhibits prostaglandin synthesis which reduces renal artery diameter (and blood flow) and thereby reducing kidney perfusion and function.
Ramipril, an ACE-inhibitor, reduces angiotensin-II production necessary for preserving glomerular filtration when the renal blood flow is reduced.
To what sort of pt shouldn’t you give ibuprofen to
Asthmatics
NSAIDs can cause bronchoconstriction in asthmatics and are therefore avoided unless strictly necessary and under close supervision (i.e. not at home).
Trimethoprim shouldn’t be used along side ….
and why?
Methotrexate
Trimethoprim is a folate antagonist, and is a direct contraindication to patients taking methotrexate (another folate antagonist) due to the risk of bone marrow toxicity. This can lead to pancytopenia and neutropenic sepsis.
When should methotrexate be withheld?
If a patient has sepsis. Need to exclude neutropenic sepsis
All diuretics cause what sort of electrolyte disturbance?
Hyponatraemia, although when they contribute to dehydration the sodium can increase too
Loop diuretic e.g.
Furosemide
Calcium-channel blocker: e.g. and side effect
Amlodipine, verapamil
Peripheral oedema
What should not be taken after an acute stroke for 2 months (duration varies)
Heparin thromboprophylaxis e.g. enoxaparin
Cardioprotective dose of aspirin; dose in tx of acute coronary syndromes and stroke
75mg; 300mg
Co-amoxiclav is a combination of …
amoxicillin and clavulanic acid
Who shouldn’t take COCP and eg
Pts who have migraine with aura as it increases their risk of stroke; microgynon
Paracetamol max dose
4g/ 24h: 2g from co-codamol and up to 2g from PRN paracetamol
Sodium normal range
135-145mmol/L
What should you assess to help narrow differential for hyPOnatraemia
Pt’s fluid status - hypovolaemic, euvolaemic, hypervolaemic
Hypernatraemia causes
All being with ‘D’
Dehydration
Drips i.e. too much IV saline
Drugs e.g. effevescent tablet preps or IV preps with a high sodium content
Diabetes insipidus - effectively the opposite of SIADH
Potassium normal range
3.5-5mmol/L
Hypokalaemia causes
DIRE
Drugs (loop and thiazide diuretics)
Inadequate intake or intestinal loss (diarrhoea/vomiting)
Renal tubular acidosis
Endocrine (Cushing’s and Conn’s syndromes)
Hyperkalaemia causes
DREAD
Drugs (potassium-sparing diuretics and ACE-inhibitors)
Renal failure
Endocrine (Addison’s disease)
Artefact (very common, due to clotted sample)
DKA (note that when insulin is given to treat DKA the potassium drops requiring regular (hourly) monitoring +/− replacement)
Microcytic anaemia causes
Iron deficiency anaemia
Thalassaemia
Sideroblastic anaemia
Normocytic anaemia causes
Anaemia of chronic disease
Acute blood loss
Haemolytic anaemia
Renal failure (chronic)
Macrocytic anaemia causes
B12*/folate deficiency (‘megaloblastic anaemia’)
Excess alcohol
Liver disease (including nonalcoholic causes)
Hypothyroidism
Haematological diseases beginning with ‘M’: myeloproliferative, myelodysplastic, multiple myeloma
High neutrophils (neutrophilia) causes
Bacterial infection
Tissue damage (inflammation/infarct/ malignancy)
Steroids
Low neutrophils (neutropenia) causes
Viral infection
Chemotherapy or radiotherapy (give urgent IV broad-spec abx)
Clozapine (antipsychotic)
Carbimazole (antithyroid)
High lymphocytes (lymphocytosis) causes
Viral infection
Lymphoma
Chronic lymphocytic leukaemia
Low platelets (thrombocytopenia) causes
Reduced production: - infection - drugs (esp. penicillamine (e.g. in rheumatoid arthritis treatment)) - myelodysplasia, myelofibrosis, myeloma
Increased destruction:
- heparin
- hypersplenism
- DIC
- ITP
- Haemolytic uraemic syndrome/ thrombotic thrombocytopenic purpura
High platelets (thrombocytosis) causes
Reactive:
- bleeding
- tissue damage (infection/inflammation/malignancy)
- post-splenectomy
Primary:
- myeloproliferative disorders
Causes of hyponatraemia if hypovolaemic
Fluid loss (especially diarrhoea/ vomiting) Addison’s disease Diuretics (any type)
Causes of hyponatraemia if euvolaemic
SIADH
Psychogenic polydipsia
Hypothyroidism
Causes of hyponatraemia if hypERvolaemic
Heart failure
Renal failure
Liver failure (causing hypoalbuminaemia)
Nutritional failure (causing hypoalbuminaemia)
Thyroid failure (hypothyroidism; can be euvolaemic too)
SIADH causes
SIADH
small cell lung tumours, Infection,
Abscess,
Drugs (especially carbamazepine and antipsychotics), and Head injury.
Prerenal (70%): Biochemical disturbance
Urea rise»_space; creatinine rise
e.g. Urea 19
3–7.5 mmol/L
Creatinine 110 (35–125 μmol/L)
Prerenal (70%): Causes
Dehydration (or if severe, shock) of any cause, e.g. sepsis, blood loss.
Renal artery stenosis - AKI in RAS is often triggered by drugs (ACEI or NSAIDs) and effectively causes hypoperfusion of the kidneys and thus a prerenal picture.
Intrinsic renal (10%): Biochemical disturbance
Urea rise << creatinine rise, bladder or hydronephrosis not palpable, e.g.: Urea 9 (3–7.5mmol/L) Creatinine 342 (35–125 μmol/L)
Intrinsic renal (10%): Causes
INTRINSIC: Ischaemia (due to prerenal AKI, causing acute tubular necrosis) Nephrotoxic antibiotics (esp. gentamicin, vancomycin, tetracyclines) Tablets (ACEI, NSAIDs) Radiological contrast Injury Injury (rhabdomyolysis) Negatively birefringent crystals (gout) Syndromes (glomerulonephridites) Inflammation (vasculitis) Cholesterol emboli
Postrenal (20%) obstructive: biochemical disturbance
Urea rise «_space;creatinine rise, bladder or hydronephrosis may be palpable depending on level of obstruction
Postrenal (20%) obstructive: causes
In lumen: stone or sloughed papilla
In wall: tumour (renal cell, transitional cell), fibrosis External pressure: benign prostatic hyperplasia, prostate cancer, lymphadenopathy, aneurysm
Raised urea indicates
Kidney injury or upper GI haemorrhage
A raised urea usually indicates renal failure; however, because it is a breakdown product of amino acids (such as globin chains in haemoglobin), it can also reflect an upper GI bleed where haemoglobin has been broken down by gastric acid into urea, which is subsequently absorbed into the blood. The same phenomenon occurs if you eat a big (and bloody) steak. Thus, a raised urea with normal creatinine in a patient who is not dehydrated (i.e. does not have prerenal failure) should prompt a look at the haemoglobin; if this has dropped then the patient probably has an upper GI bleed.
Vit K-dependent clotting factors
2,7,9,10 measured by PT/INR
Raised bilirubin alone indicates …
haemolysis
Raised alk phos indicates
ALKPHOS Any fracture, Liver damage (posthepatic), K (for kancer), Paget’s disease of bone and Pregnancy, Hyperparathyroidism, Osteomalacia, Surgery.
Which result do you check to change a levothyroxine dose for pts with hyPOthyroidism
TSH
tsh range <0.5 mIU/L
decrease thyroxine dose
tsh range 0.5-5 mIU/L
nil action - keep same dose thyroxine
tsh range >5 mIU/L
Increase thyroxine dose
Prehepatic
Bilirubin ⇑
Haemolysis
Gilbert’s and Crigler–Najjar syndromes
Intrahepatic
Bilirubin ⇑ and AST/ALT ⇑
Fatty liver
Hepatitis*
Cirrhosis*
((1) alcohol, (2) viruses (Hepatitis A–E, CMV and EBV), (3) drugs (paracetamol overdose, statins, rifampicin), and (4) autoimmune (primary biliary cirrhosis, primary sclerosing cholangitis and autoimmune hepatitis)
Malignancy (primary or secondary)
Metabolic: Wilson’s disease/haemochromatosis
Heart failure (causing hepatic congestion)
Posthepatic (obstructive)
Bilirubin ⇑ and ALP ⇑
In lumen: stone (gallstone), drugs causing cholestasis - Flucloxacillin, coamoxiclav, nitrofurantoin, steroids and sulphonylureas.
In wall: tumour (cholangiocarcinoma), primary biliary cirrhosis, sclerosing cholangitis
Extrinsic pressure: pancreatic or gastric cancer, lymph node