Endocrine System Flashcards
Insulin
Mechanism of Action
Exogenous replacement of deficient hormone to stimulate glucose absorption, glycogenesis, lipogenesis, proteosynthesis and inhibit gluconeogeneis and ketogenesis, also increases K+ absorption and act in short, intermediate or long-term (biphasic = rapid and intermediate)
Insulin
Indications
T1DM, poorly controlld T2DM, DKA, peri-operative glycaemic control, hyperkalaemia
Insulin
Contra-indications
Reduced clearance proportionate to renal impairment (further renal imp req’s lower dose)
Insulin
Side Effects
Hypoglycaemia (coma/death), lipohypertrophy at injection site
Insulin
Interactions
Corticosteroids reduce effect
Sulphylurea
Name
Gliclazide
Sulphylurea (Gliclazide)
Mechanism of Action
Lowers blood glucose via stimulation of pancreatic insulin secretion - blocks ATP-dependent K+ channels in beta-cell membranes causing depolarisation - requires residual pancreatic function
Sulphylurea (Gliclazide)
Indications
T2DM - when metformin is C/I or combined if insufficient
Sulphylurea (Gliclazide)
Contraindications
Hepatic/renal imp, high risk of hypoglycaemia, T1DM, DKA, pre-coma/coma
Sulphylurea (Gliclazide)
Side effects
GI upset, hypoglycaemia, weight gain, hyponatraemia (SIADH), cholestatic hepatitis
Sulphylurea (Gliclazide)
Interactions
Other diabetic drugs
Drugs that increase glucose - steroid, thiazides, loops
Biguanide
Name
Metformin
Biguanide (Metformin)
Mechanism of action
Increases insulin sensitivity and glucose uptake in skeletal muscle, suppresses hepatic glucose production by AMPK activation
Biguanide (Metformin)
Indications
T2DM - first choice for control of blood glucose
Biguanide (Metformin)
Contraindications
Renal impairment, AKI, severe tissue hypoxia, acute alcohol intoxication, chronic overuse
Biguanide (Metformin)
Side effects
Lactic acidosis with severe liver/renal disease, GI upset (dose dep, common), reduced appetite, weight loss, vitamin B12 resorption
Biguanide (Metformin)
Interactions
IV contrast media (CKD/lactic acidosis risk), drugs that increase glucose, recent hypoxia (MI/sepsis)
Thyroid Hormones
Names
T3 - Liothyronine (active, IV use in emergency)
T4 - Levothyroxine (pro-hormone)
Levothyroxine
Mechanism of action
Agonist of thyroid receptors
Levothyroxine
Indications
Primary or Secondary (low TSH) hypothyroidism
Levothyroxine
Contraindications
CAD, hypopituitary state must initiate corticosteroid before thyroid therapy to avoid Addisonian crisis
Levothyroxine
Side effects
As Hyperthyroidism - GI, cardiac and neuro manifestations
Levothyroxine
Interactions
GI absorption reduced by antacids/Ca/Fe salts
CYP450 inducers reduce efficacy
Levothyroxine may change metabolism affecting insulin and warfarin
Anti-thyroid
Name
Carbimazole
Carbimazole
Mechanism of action
Converted to thimazole which inhibits coupling of iodothyronine to suppress T3/4 synthesis
Carbimazole
Indications
Hyperthyroidism, preparing for thyroidectomy, pre-radio-iodine therapy
Carbimazole
Contraindications
Hypersensitivity, serious haematological conditions or hepatic insufficiency
Carbimazole
Side effects
GI upset, bone marrow suppression, lymphadenopathy, hypersensitivity, insulin autoimmune syndrome, bleeding
Carbimazole
Interactions
Vitamin K antagonist - intensifies anticoagulants
Increase prednisolone clearance
Bisphosphantes
Name
Alendronate, Zoledronate, Disodium pamidronate
Bisphosphonates
Mechanism of action
Inhibit action of osteoclast by accumulating within and inhibiting their activity and inducing apoptosis to increase bone mass
Bisphosphonates
Indications
Osteoporosis (elderly, post-menopausal), severe hypercalcaemia (malignancy, myeloma, Paget’s disease of bone) can be given IV
Bisphosphonates
Contraindications
Renal impairment, hypocalcaemia, upper GI disorders, smoker/dental disease
Bisphosphonates
Side effects
Oesophagitis, hypophosphataemia, osteonecrosis of the jaw, atypical femoral fracture
Bisphosphonates
Interactions
Bind to calcium in stomach/anatacids/iron salts, reducing effectiveness
Calcium/Vitamin D supplements
Names
Calcium carbonate, colecalciferol, calcium gluconate
Ca/vD supplements
Mechanism of action
Restoration of bone mass/density to prevent fraction - seen in CKD (renal osteodystrophy), Ca increases myocardial threshold/arrhythmia risk in hyperkalaemia
Ca/vD supplements
Indications
Osteoporosis, CKD, severe hyperkalaemia, asx hypocalcaemia (tetany, petechiae, paraesthesia), vD deficiency (Rickett’s, osteomalacia)
Ca/vD supplements
Contraindications
Hypercalcaemia
Ca/vD supplements
Side effects
Dyspepsia, constipation, CV collapse if IV too fast
Ca/vD supplements
Interactions
Oral Ca reduces Fe Bisphosphonates Tetracycline Levothyroxine - Sodium bicarbonate IVI may precipitate
Calcium gluconate emergency dosage
10mL at 10% over 10 minutes
Mineralocorticoid
Name
Fludrocortisone
Mineralocorticoid
Mechanism of action
Enhances deposition of liver glycogen, retains Na+, increases K+ secretion
Mineralocorticoid
Indications
Adrenocortical insufficiency e.g. Addison’s disease
Mineralocorticoid
Contraindications
systemic infections, oedematous state
Mineralocorticoid
Side effects
Anti-inflammatory, immunosuppressive, hypertensive, MSK pain/weakness, cushingoid, GI upset
Mineralocorticoid
Interactions
Extensive:
NSAIDs, thyroid meds, anti-diabetes meds, anticoagulants/anti-hypertensives, immunosuppressants
Mineralocorticoid
Prescription advice
Risk of acute adrenal insufficiency syndrome if suddenly stopped
Sitagliptin
When to use first line
DDP-4 inhibitor if eGFR <30mls/min
Glitazones
Side effects
Weight gain, fluid retention, liver dysfunction, fractures
