Top 100 drugs Flashcards
What are Dipeptidylpeptidase-4 inhibitors indicated for?
Type 2 Diabetes: In combination with metformin (or other hyperglycaemic agents) where blood glucose is inadequately controlled.
As a single agent where metformin is contraindicated or not tolerated.
What is the mechanism of action for DPP-4 inhibitors?
Incretins and glucose-dependent insulinotropic peptide are released by the intestine throughout the day, and particularly in response to food - these promote the secretion of insulin and suppress glucagon release, thus lowering blood glucose. Incretins are rapidly inactivated by the enzyme DPP-4. DPP-4 inhibitors therefore prevent the degradation of incretins and increase plasma concentrations of their active forms, lowering blood glucose concentrations.
Which are less likely to cause HYPOglycaemia, DPP-4 inhibitors or sulphonylureas ?
DPP-4 inhibitors - As the action of incretins are glucose dependent they do not stimulate the secretion of insulin at normal blood glucose levels or suppress glucagon release in response to hypoglycaemia. This means DPP-4 inhibitors are less likely to cause hypoglycaemia than sulphonylureas which stimulate insulin secretion irrespective of blood glucose.
Name the DDP-4 inhibitors
Alogliptin, Sitagliptin, Linagliptin and Saxagliptin
What are the potential adverse effects associated with the use of DPP-4 inhibitors?
- HYPOglycaemia where DPP-4 inhibitors are being used in combination with sulphonylureas and/or insulin
- All DPP-4 inhibitors are associated with acute pancreatitis which typically presents as persistent abdominal pain resolved upon stopping of the drug
- GI upset
- Headache
- Nasopharyngitis
- Peripheral oedema
Can DPP-4 inhibitors be used to treat Type 1 diabetes?
No
Can DPP-4 inhibitors be used to treat ketoacidosis?
No
Can DPP-4 inhibitors be used during pregnancy or breastfeeding?
No
How are DPP-4 inhibitors excreted?
Renally
When should DPP-4s be dose adjusted?
During moderate to severe renal impairment
When are DPP-4 inhibitors contraindicated?
DPP-4 inhibitors are contraindicated in patients with hypersensitivity to the drug class
When should DPP-4 inhibitors be used with caution?
- Elderly (>80 years)
- History of pancreatitis
Use of which other drug classes increases the risk of HYPOglycaemia in concurrent use with DPP-4 inhibitors?
- Sulphonylureas
- Insulin
- Alcohol
Which drug class may mask the symptoms of HYPOglycaemia?
Beta-blockers
What is the typical dosing of DPP-4 inhibitors?
Once daily
What quantity of the the daily dose of a DPP-4 inhibitor dose a combined formulation with metformin contain?
Half the daily dose
What is the key counselling point when advising a patient on the use of a DPP-4 inhibitor?
Acute Pancreatitis - seek medical attention if you develop severe or acute stomach pain radiating to the back
Which indicator is used to assess glycaemic control when using a DPP-4 inhibitor?
HbA1c
What are the target HbA1c levels for monotherapy and combined therapy with a DPP-4 inhibitor?
Monotherapy - <48mmol/mol
Combination therapy - <53mmol/mol
What HBA1c is generally a trigger to intensify treatment with an additional agent when using a formulation of a DPP-4 inhibitor?
> 58mmol/mol
What advantage do metformin and SGLT2 inhibitors have over use of DPP-4 inhibitors?
They reduce the risk of vascular complications
The efficacy of DPP-4 inhibitors is reduced by which medications that elevate levels of blood glucose?
- Prednisolone
- Thiazide
- Loop diuretics
What is the indication for metformin?
Type 2 diabetes as a a monotherapy or in combination with DPP-4 inhibitors, Sulphonylureas, or insulin
What is the mechanism of action for metformin?
Metformin (a biguanide) lowers blood glucose by reducing hepatic glucose output (glycogenolysis and gluconeogenesis)) and to a lesser extend increasing the uptake and utilisation of glucose by skeletal muscle. Metformin achieves its mechanism of action through activation of AMP (adenosine monophosphate- activated) kinase which acts as a metabolic sensor.
What are some key adverse effects of metformin use?
GI upset
- Nausea
- Vomiting
- Taste disturbance
- Diarrhoea
- Lactic acidosis
When should metformin be used with caution?
Renal impairment
Hepatic impairment
Chronic alcohol abuse
At what eGFR does metformin require dose adjusting, and what level dose it require stopping metformin?
Dose reduction - <45ml/min per 1.73m2
Stopped - <30ml/min per 1.73m2
When should metformin be held?
AKI
Severe tissue hypoxia (e.g. in sepsis, cardiac or respiratory failure, or myocardial infarction)
Acute alcohol intoxication
Which three medications reduce the efficacy of metformin?
Prednisolone
Thiazide
Loop diuretics
When and for how long should metformin be withheld regarding IV CONTRAST MEDIA?
Metformin must be withheld before and for 48 hours after the injection of IV contrast media when there is an increased risk of renal impairment, metformin accumulation, and lactic acidosis.
Which other drugs that have the potential to impair renal function should be used in caution with metformin?
ACE inhibitors
NSAIDs
Diuretics
What formulation of metformin should patients be started on initially, and why?
Standard release to minimise GI side effects
What is a common starting regimen for metformin?
500mg OD with breakfast, increasing by 500mg weekly to 500-850mg TDS with meals
What are the key points when counselling a patient who has been newly started on metformin?
- Inform their Dr they are taking metformin before having an X-ray or operation
- Seek urgent medical advice if they develop significant illness such as breathlessness, fever, or chest pain, as, in addition to treating the illness, metformin may need to be stopped or withheld due to the risk of a side effect called lactic acidosis
Ideally when should renal function be measured in patients taking metformin?
Before starting treatment and then at least annually during treatment. Renal function should be measured more frequenty (at least twice per yer) in patients with deteriorating renal function or at increased risk of renal impairment.
How should glycaemic control be measured in patients taking metformin and what is the target level when metformin is being used as a single agent?
HbA1c - <48mmol/mol
Does metformin stimulate insulin scretion?
No
When and how should treatment of type 2 diabetes be intensified when using metformin as a single agent?
A second agent should be added if HbA1c >58mmol/mol and a new target of <53 mmol/mol is set (balancing the risk of hyperglycaemia against the risk of treatment, in particular hypoglycaemia)
At what point and for long should increased physical activity be recommended before meformin is initiated?
HbA1c >48 mmol/mol
At least three months before metformin initiation
What primarily increases insulin resistance?
Increased body weight
What kind of hormone is insulin?
Anabolic
Does metformin cause weight gain?
No. Unlike the sulphonylureas, metformin does not stimulate the secretion of insulin, which as an anabolic hormone causes weight gain and can worsen diabetes mellitus over the long term.
What are the sulphonylureas indicated for?
Type 2 diabetes in combination with metformin (and/or other hyperglycaemic agents) or as a single agent to control blood glucose levels where metformin is contraindicated
What drug class is gliclazide
Sulphonylurea
What is the mechanism of action of sulphonylureas?
They stimulate pancreatic insulin secretion by blocking ATP dependen K+ channels in pancreatic beta-membranes causing depolarisation of the cell membranes and the opening of Ca2+ channels. This increases intracellular Ca2+ concentrations, stimulating the secretion of insulin. Sulphonylureas are only effective in patients with residual pancreas function.
What are the potential adverse effects associated with the use of sulphonylureas?
- GI upset
- HYPOglycaemia
- Rare sensitivity reactions (hepatic toxicity, drug hypersensitivity syndrome, and haematological abnormalities)
Where are the sulphonylureas metabolised?
The liver
How are the sulphonylureas excreted?
Unchanged drug and metabolites are excreted renally
Can sulphonylureas be used in renal impairment?
Yes, they should be used with caution in those with mild-moderate renal impairment due to the risk of hypoglycaemia. The lowest possible dose should be used and blood glucose should be carefully monitored
Gliclazide can be used in renal impairment but careful monitoring of blood glucose is essential
When should sulphonylreas be used with caution?
In those with increased risk of HYPOglycaemia:
- Hepatic impairment (reduced gluconeogenesis)
- Malnutrition
- Adrenal or pituitary insufficiency (lack of counter-regulatory hormones)
- Elderly
When is a dose adjustment required for the use of sulphonylureas?
In patients with hepatic impairment
The risk of HYPOglycaemia is increased by the co-prescription of which other drugs with the sulphonylureas?
Alchohol
Antidiabetic drugs:
- Metformin
- DPP-4 inhibitors
- Thiazolidinediones (*glitazones)
- Insulin
The efficacy of sulphonylureas are effected by which other drugs that elevate blood glucose?
- Prednisolone
- Thiazide
- Loop diuretics
What dose of standard release gliclazide has the same glucose lowerin effect as 30mg MR gliclazide?
80mg
What is a standard starting regimen for gliclazide?
40-80mg OD, then increased of 160-320mg if necessary (in 2x divided doses when exceeding 160mg)
When/how should sulphonyolureas be taken?
With meals (OD with breakfast or BD with breakfast and dinner for higher doses)
What are the key points when counselling a patient about the use of sulphonylureas such as gliclazide?
- Should be used in addition to healhy lifestyle measures
- Watch out for the symptoms of HYPOglycamia (dizziness, sweating, nausea, and confusion)
How is glycaemic control measured when using sulphonylureas?
HbA1c
What is the target HbA1c of a patient using gliclazide as a single agent to treat type-2 diabetes
<48 mmol/mol
When and how is treatment intensified for a patient using gliclazide as a single agent to treat type-2 diabtes
Treatment is itensified with the addiion of a second agent when HbA1c exceeds >58 mmol/mol and a new target of <53 mmol/mol is set
Which are more expensive; sulphonylureas or DPP-4 inhibitors
DPP-4 inhibitors are newer and more expensive
When are sulphonylureas contraindicated?
In the presence of ketoacidosis
Can sulphonylureas be used in pregnancy or breastfeeding?
No, due to the possible risk of neonatal or infant hypoglycaemia
During acute illness what should happen to treatment with sulphonylureas?
During acute illness, insulin resistance increases and renal and hepatic function may be impaired. As such oral hypoglycaemics become less effective at controlling blood glucose and side effects are more likely. Insulin treatment may be required temporarily as the dosage can be adjusted more easily than that of oral medications.
What drug class is prednisolone?
Corticosteroid
(Glucocorticoids)
What drug class is hydrocortisone?
Corticosteroid
(Glucocorticoids)
What drug class is dexamethasone?
Corticosteroid
(Glucocorticoids)
What are he indications for corticosteroids (glucocorticoids)
- To treat allergic and inflammatory disorders
- Supression of autoimmune disease
- In the treatment fof some cancers as part of chemotherapy or to reduce tumour-associated swelling
- Hormone replacement in adrenal insufficiency hypopituitarism
What are the mechanismsof action of corticosteroids (glucocorticoids)?
These corticosteroids mainly exert glucocorticoid effects.They bind to the cytosolic glucocorticoid receptors, which then translocate to the nucleus and bind to the glucocorticoid-response elements, which regulate gene expression. They upregulate antiinflammatory genes and downregulate pro-inflammatory genes (e.g. cytokines, tumour necrosis factor-alpha etc). Direct actions on inflammatory cells include suppression of circulating monocytes and eosinophils.
Their metabolic effects include increased gluconeogenesis from increased circulating amino and fatty acids released by catabolism of muscle and fat.
These drugs also have mineralocorticoid effects, stimulating sodium and water retention and potassium excretion in the renal tubule.
What are the main adverse effects of cortcosteroid use (glucocorticoids)?
- Immunosuppression
- Diabetes mellitus
- Osteoporosis
- Cushing’s syndrome
- Skin thinning
- Gastritis and peptic ulcers
- Proximal muscle weakness
- Bruising
- Insomnia
- Confusion
- Psychosis
- Suicidal ideation
- HYPERtension
- HYPOkalaemia
- Oedema
- Adrenal supression
- Glaucoma
What immune side effects can corticosteroid use cause?
Immunosuppression
What metabolic side effects can corticosteroid use cause?
Diabetes mellitus
Osteoporosis
What side effects can result from increased catabolism associated with corticosteroid use?
Skin thinning
Gastritis
Easy bruising
Proximal muscle weaknes
What behavioural side effects can result from corticosteroid use?
Insomnia
Confusion
Psychosis
Suicidal ideation
What side effects can be caused by the mineralcorticoid effects of corticosteroid use?
Hypertension
Hypokalaemia
Oedema
Why is slow withdrawal of corticoid sterioids required?
To prevent Addisonian crisis and to allow for the recovery of endogenous adrenal function, and to prevent chronic glucocorticoid deficiency which presents as fatigue, weight loss and arthralgia (joint stiffness)
What is the MHRA warning for the use of systemic cortcosteroids
Rare risk of central serous chorioretinopathy wih local as well as systemic administration (Augut 207)
When should corticosteroids be prescribed with caution?
People with infection
Children - in whom it may suppress growh
How do corticosteroids interact with NSAIDs?
They both increase the rik of peptic ulceration and GI bleeding
Which drug classes increases the risk of HYPOkalaemia when taken with corticosteroids such as prednisolone?
Beta2-agonists
Theophylline
Loop diuretics
Thiazide diuretics
Which medications reduce the efficacy of corticosteroids such as prednisolone?
Cytochrome P450 inducers e.g
- phenytoin
- rifampicin
- carbamazepine
List the medications that interact wih corticosteroids
NSAIDs
Loop diuretics
Thiazide diuretcs
Beta2-agonists
Phenytoin
Carbamazepine
Rifampicin
When in the day should OD corticostroids be given and why?
In the morning to mimic the body’s natural circadian rythm and avoid insomnia
Between prednisolone, hydrocortisone, and dexamethasone, which is more potent and what are the equivalent dosages?
Dexamethasone is the more potent of the three
750micrograms dex = 5mg pred = 20mg hydrocort
What dose of dexamethasone is typically prescribed in emergencies (e.g. treatment of vasogenic oedema that may surround brain tumours)?
8mg BD IV or orally - then weaned down slowly as symptoms improve
What should happen to corticosteroid therapy during acute illness?
The dose is typically doubled as patients on long term steroids are usualy unable to increase endogenous secretion of cortisol in times of stress, therefore additional exogenous corticosteroid may be required.
When should courses of prednisolone be tapered down in adults?
- When the patient has received 40mg or more OD for 1 week or more
- Been given repeat doses in the evening
- Received more than 3 weeks of treatment
- Recently received repeat courses (particulalry in the last 3 weeks)
- Taken a short course within 1 year of stopping long term therapy
- Other possible causes of adrenal suppression
What is the typical dose of prednisolone used in an adult with an acute exacerbation of COPD?
30mg OD PO for 7-14 days
What is the typical dose of prednisolone used in an adult with an acute exacerbation of asthma?
40mg OD PO for at least 5 days
When should courses of prednisolone be tapered down in children?
- When the patient has received 40mg or more OD for 1 week or more / 2mg/kg OD for 1 week or more / 1mg/kg OD for 1 month or more
- Been given repeat doses in the evening
- Received more than 3 weeks of treatment
- Recently received repeat courses (particulalry in the last 3 weeks)
- Taken a short course within 1 year of stopping long term therapy
- Other possible causes of adrenal suppression
What drugs can be given to limit adverse effects of corticosteroid use in patients with relevant risk factors?
Bisphosphonates
PPIs
Which corticosteroid is typically used and how when oral aministration is not appropriate (e.g. inflammatory bowel disease flares, anaphylaxis, etc)?
IV hydrocortisone
When may the co-prescription of steroid sparing agents be necessary to limit adverse effects with corticosteroids? Which agents are typically co-prescribed?
In long term treatment of consitions such as inflammatory arthritis where the lowest dose of oral prednisolone is used to treat the disease and limit adverse effects.
Commonly co-prescribed drugs in these consitions are methotrexate and azathioprine.
What are the key points when counselling a patient newly started on corticosteroids such as oral prednisolone?
- Do not stop treatment suddnly
- Carry a steroid card incase they need treatment
- Discus the risks of long term steroid use such as osteoporosis, bone fracture, and diabetes so the patient can make an informed decision about their therapy
How should the efficacy of prednisolone treatment be monitored?
This depends on the condition being treated and the anticipated adverse effects
- Peak expiratory flow in excerbations of asthma and COPD
- Blood inflammatory markers for inflammaory arthritis
- HbA1c and blood gluose to monitor for potential diabetic levels
- DEXA scans to measure bone densiy for potntil osteoporosis
How do corticosteroids affect ACTH (pituitary adrenocorticotropic hormone) secretion and what are the consequences of this?
ACTH secretion is suppressed
- stimulus of normal adrenal cortisol production switched off
- Prolonged treatment causes adrenal atrophy which prevents endogenous cortisol secretion
- Sudden withdrawal can cause Addisonian crisis with cardiovascular collapse
- Chronic glucorticoid deficiency during withdrawal may present as fatigue, weight loss, and arthralgia
Concurrent therapy with drug class increases insulin requirements?
Systemic corticosteroids
What are the indications for insulin?
- Insulin replacement in people with type 1 diabetes and control of blood glucose in type 2 diabetes where oral hypoglycaemic treatment is inadequate or poorly tolerated
- Given intravenously, in the treatment of diabetic emergencies such as diabetic ketoacidosis and hyperglycaemic hyperosmolar syndrome
- Given alongside glucose to treat hyperglycaemia while other measures are being initiated
What are the main adverse effects of insulin use?
- Hypoglycaemia
- Fat overgrowth in repeated SC use at the site of injection
What are the 5 types of insulin?
- Rapid acting
- Short acting
- Intermediate acting
- Long acting
- Biphasic
What type of insulin is insulin glargine
Long acting
What type of insulin is insulin degludec?
Long acting
What type of insulin is insulin detemir?
Long acting
What type of insulin is insulin aspart?
Rapid acting
What type of insulin is insulin isophane?
Intermediate acting
What type of insulin is insulin lispro?
Rapid acting
What type of insulin is insulin glulisine?
Rapid acting
What type of insulin is soluble insulin?
Short acting
What types of insulin are usually in a biphasic insulin preparation?
Rapid and intermediate
What type of insulin is in Lantus preparations?
Glargine
What type of insulin is in Humalog preparations?
Lispro
What type of insulin is in Toujeo preparations?
Glargine
What type of insulin is in Levemir preparations?
Detemir
What kind of insulin is in Tresiba preparations?
Degludec
What kind of insulin is in Actrapid preparations?
Soluble insulin
What kind of insulin is in Fiasp prepaprations?
Aspart
What kind of insulin is in Humalog S preparations?
Soluble insulin
What kind of insulin is in Humalin I preparations?
Isophane
What kind of insulin is in Semglee preparations?
Glargine(-yfgn)
What is the mechanism of action of insulin in the treatment of HYPERkalaemia?
Insulin drives potassium ions into the cells, reducing serum K+ levels. However, when insulin treatment is stopped K+ leakback out of cells, so this is only a short-term measure while other treatments are initiated.
What is the general mechanism of action of insulin in the treatment of type 1 and 2 diabetes?
Insulin stimulates th uptake of glucose from circulaion into tissues, including skeletal muscle and fat, and increasess the use of glucose as an energy source. It also stimulates glycogen, lipid and protein synthesis and inhibits gluconeogenesis and ketogenesis.
Which yp of insulin is used whn IV insulin is required?
Soluble inulin (Actrapid)
Which types of insulin (inc. brand names) are typically used in a basal-bolus regimen?
Inulin glargine (Lantus) and insulin aspart (NovoRapid)
What is soluble insulin administered with in the treatment of HYPERkalaemia and why?
Glucose (20%), to avoid hypoglycaemia
What are the key points when counselling a patient on insulin use?
- Treatment does not replace the need to maintain helthy lifestyle such as exercise and diet
- Risk of hypoglycaemia and symptoms (i.e. dizziness, agitation, nausea, sweating and confusion)
- If they should develop hypoglycaemia they should take a sugary snack followed something starchy (i.e. sandwich etc)
If a correction dose of insulin is necessary what kind of insulin should be used and why?
Rapid acting insulin such as insulin aspart. Short acting insulins (Actrapid) should be avoided due to the 2-3 hour delay to their peak effect)
Where insulin is being given as a continuous IV infusion what should be monitored in addiion to serum glucose and how often?
Serum potassium ion (K+) levels should be monitored every 4 hours ideally to assess whether replacement is required
What should be considered in patients with renal impairment during insulin therapy?
The clearance of insulin will be reduced and there will therefore be an increased risk of hypoglycaemia
What are the 3 main types of long acting insulin?
Detemir, Glargine and Degludec
What are the 2 main types of rapid acting insulin
Aspart and Lispro
What is the main type of intermediate acting insulin?
Isophane
What is the main type of short acting insulin?
Soluble insulin
Which type of insulin preparations are used in a “twice daily” regimen?
Biphasic (rapid acting in combination with a intermediate acting insulin)
What are the indications for thyroid hormones?
- The treatment of primary hypothyroidism
- The treatment of hypothyroidism secondary to hypopituitarism
Levothyroxine is a synthetic version of which thyroid hormone?
Thyroxine (T4)
Liothyronine is a synthetic version of which thyroid homone?
Triiodothyronine (T3)
What is the mechanism of action of thyroid replacement hormones?
The thyroid gland produces thyroxine (T4) which is converted into the more active triiodothyronine (T3) in target tissues. These hormones regulate metabolism and growth and deficiency of these hormones causes hypothyroidism which presents as lethargy, weight gain, constipation and the slowing of mental processes.
Which thyroid hormone replacement is usually reserved for the treatment of severe or acute hypothyroidism?
Liothyronine as it has a shorter half-life and quicker onset (a few hours) and offset than levothyroxine.
What are the potential adverse effects associated with the use of thyroid replacement hormones?
Usually du to excessive dosing these symptoms are typically similar to those of hyperthyroidism:
Gastrointestinal
- diarrhoea
- weight loss
- vomiting
Cardiac
- palpittions
- arrythmias
- angina
Neurological
- tremor
- restlessness
- insomnia
Do thyroid replacement hormones increase heart rate?
Yes
What are the warnings associated wih thyroid hormone replacement therapies such as levothyroxine and liothyronine?
- As thyroid hormones increase heart rate and metabolism they can precipitate cardiac ischaemia in people with coronary artery disease, in whom therapy should be started at a low dose and with careful monitoring
- In hypopituitarism, corticosteroid therapy must be started before thyroid hormone replacement to avoid the precipitation of Addisonian crisis
How should treatment with thyroid hormone replacement be initiated in patients with coronary artery disease and why?
Thyroid replacement should be initiated carefully at a low dose and monitored closely to prevent the preciptation of cardiac ischaemia
How should thyroid hormone replacement therapy be started in patients with hypopituitarism and why?
Before thyroid hormone replacement is initiated the patient should be started on coticosteroid therapy to prevent the precipitation of Addisonian crisis
Which medications interact with thyroid hormones?
- Antacids
- Iron an calcium salts
- Cytochrome P450 inducers (carbemazepine and phenytoin)
- Insulin
- Warfarin
How do thyroid hormones interact with antacids and calcium and iron salts, and what precautions need to be taken?
The GI absorption of levothyroxine is reduced by antacids, calcium and iron salts, and as such adminitration of these drugs needs to be separated by at least 4 hours
When does a dose adjustment of levothyroxine need to be considered?
In patients taking cytochrome P450 inducers such as carbemazepine or phenytoin
How do thyroid hormones intract with warfarin?
Levothyroxine-induced chnges in metabolism can enhance the effects of warfarin
How does levothyroxine interact with insulin?
Levothyroxine-induced changes in metabolism can increase insulin and oral hypoglycaemic requirements
What is a typical starting dose of levothyroxine?
50-100 micrograms OD
What is a typical starting dose of levothyroxine in elderly patients with cardiac disease?
25 micrograms OD
How is liothyronine typically administred?
Intravenously
What is a typical maintenance dose of levothyroxine?
50-200 micrograms OD
What are the key points when counselling a patient on the use of levothyroxine?
- Treatment is for life
- It may take some time for them to feel back to “normal”
- Calcium or iron replacement and antacids should be taken at least 4 hours between these treatments and levothyroxine
- The signs of too much treatment include shakiness, anxiety, sleeplessness and diarrhoea
How often should thyroid function tests be performed for a patient taking levothyroxine?
3 months after initiation and then annually afterwrds
How is dosing guided in the initial weeks and months of treatment with levothyroxine?
Dosing is adjusted an guided according to symptoms
What measurement is used as the main guide to dosing with levothyroxine after the first 3 months of treatment?
TSH
What symptoms might patients experience shortly after initiating levothyroxine? How should this be dealt with and why?
Patients may begin to experience hyperthyroid symptoms shortly after starting levothyroxine. If this happens therapy should be continued at a lower dose while monitoring for reemergence of symptomsof hypothyroidism. Thyroid function tests will be unhelpful at this stage as TSH and T4 will likely be increased; TSH as this takes several weks for this to decrease following initiation of therapy and T4 because of the levothyroxine therapy.
What is a possible cause for a patient to develop symptoms of thyroid dysfunction during treatment with levothyroxine?
Switching to a different formulation of levothyroxine
What is the MHRA warning associated with levothyroxine?
New prescribing advice for patient who experience symptoms when switching between different levothyroxine products (May 2021)
What should be considered if a patient is switching to a different formulation of levothyroxine?
Thyroid function tests should be performed if the patient starts to experience symptoms of thyroid dysfunction. If symptoms are persistent, prescribing a formulation of levothyroxine that the patient is known to consistently tolerant of is recommended. If the patient remains symptomatic try switching the patient to an oral solution formulation.
Can levothyroxine be used in pregnancy and breastfeeding?
Yes, the amount excreted in breastmilk is too small to affect neonatal hypothyroidism tets
What are th clinical indications for the use of SGLT2 inhibitors?
- Type 2 diabetes in combination with other antidiabetic drugs or as a monotherapy if metformin is not tolerated
- Symptomatic chronic heart failure wih reduced ejection fraction, inadequately controlled with a bta-blocker, ACEi, and an aldosterone antagonist
- Chronic kidney disease with albuminuria, alongside an ACEi or ARB
Name the SGLT2 inhibitors
- Dapagliflozin
- Empagliflozin
- Canagliflozin
What is the mechanism of action of SGLT2 inhibitors with regards to the treatment of type 2 diabetes?
These drugs selectively and reversibly inhibit the sodium-glucose co-transporter 2 (SGLT2) in the proximal convuluted tubule of the nephron.
SGLT2 mediates active transport of glucose and sodium from filtrate into the blood, controlling the sodium content of the filtrate and recovering most of the filtered glucose.
SGLT2 inhibition impairs glucose resorption in the nephron increasing renal excretion of glucose an treating hyperglycaemia.
What is the mechanism of action of SGLT2 inhibitors with regards to the treatment of chronic heart failure?
These drugs selectively and reversibly inhibit the sodium-glucose co-transporter 2 (SGLT2) in the proximal convuluted tubule of the nephron.
SGLT2 mediates active transport of glucose and sodium from filtrate into the blood, controlling the sodium content of the filtrate and recovering most of the filtered glucose.
By increasing renal sodium excretion and water excretion, SGLT2 inhibitors reduce extracellular water volume, blood pressure an cardiac preload.
What is the mechanismof action of SGLT2 inhibitors with regards to the teatment ofchronic kidney disease wih albuminuria?
These drugs selectively and reversibly inhibit the sodium-glucose co-transporter 2 (SGLT2) in the proximal convuluted tubule of the nephron.
SGLT2 mediates active transport of glucose and sodium from filtrate into the blood, controlling the sodium content of the filtrate and recovering most of the filtered glucose.
Increased sodium delivery to the macula densa triggers tubuloglomerular feedback mechanisms that reduce intraglomerular pressure
What are the MHRA warnings asociated with the use of SGLT2 inhibitors?
- Risk of diabetic ketoacidosis (April 2016)
- Monitor ketone levels during treatment interuption for surgical procedures or acute serious medical illness (March 2020)
- Reports of Fournier’s gangrene (necrotising fasciitis of genitalia or perineum) (February 2019)
- Dapagliflozin specific -5mg should no longer be used inthetreatment of type 1 diabetes mellitus (November 2021)
When should SGLT2 inhibitors be withheld?
SGLT2 inhibitors should be withhld during acute illness (sick day rules) that causes or presnts a risk of volume depletion or hypotension
Which other drugs do SGLT2 inhibitors interact wih and to what effect?
- Glucose lowering medications such as insulin or sulphonylureas, etc - augments their effects - increases the risk of hypogycamia
- Blood pressure lowering medications - augments their effects - increased risk of hypotension
- Diuretics - augments their effects - increased risk of volume depletion
What are the most clinically significant potential adverse effects of the use of SGLT2 inhibitors?
- Hpoglycaemia (when use with other hypoglycaemic agents)
- Increased thirst (due to increased osmotic diuresis
- Increased risk of genital and urinary infections (due to glycosuria)
- Euglycaemic ketoacidosis (more common in the treatment of type 1 diabetes mellitus)
What general prescribing advice is given when starting an SGLT2 inhibitor for the treatmen of heart failure or CKD in a diabetic patient?
Other antihyperglycaemic medications may have to be ose adjusted to accomodate the glucose lowerin effect of theSGLT2 inhibitor
What is a typical dose of canagliflozin?
100mg OD
What is a typical dose of dapagliflozin?
10mg OD
What is the simplified mechanism of action of SGLT2 inhibitors?
Thy increase the amount of suger passed in the urine, which in turn increases the amount of water passed
How would you establish if a patient being treated with an SGLT2 inhibitor has euglycaemic dibetic ketoacidosis?
Check for urinary ketones - withhold the drug, check acid base status (e.g.by arterial blod or venous blood gas analysis) and seek expert advise
When should SGLT2 inhibitors be restarted after they have been withheld in acute illness?
When the patient feels better (i.e. is asymptomatic)