Miscellaneous Pharmacology Flashcards
Tricyclic Antidepressant Overdose eg. amitriptyline
Early features relate to anticholinergic properties: dry mouth, dilated pupils, agitation, sinus tachycardia, blurred vision.
Features of severe poisoning include:
arrhythmias
seizures
metabolic acidosis
coma
ECG changes include:
sinus tachycardia
widening of QRS
prolongation of QT interval
Widening of QRS > 100ms is associated with an increased risk of seizures whilst QRS > 160ms is associated with ventricular arrhythmias
Management;
Management
IV bicarbonate- first-line therapy for hypotension or arrhythmias/ indications include widening of the QRS interval >100 msec or a ventricular arrhythmia
other drugs for arrhythmias
NB- intravenous lipid emulsion is increasingly used to bind free drug and reduce toxicity/ dialysis is ineffective in removing tricyclics
Paracetamol Overdose
Increased risk of hepatotoxicity;
patients taking liver enzyme-inducing drugs (rifampicin, phenytoin, carbamazepine, chronic alcohol excess, St John’s Wort)
malnourished patients (e.g. anorexia nervosa) or patients who have not eaten for a few days
NB- acute alcohol intake is better than chronic alcohol excess (may be protective)
The minority of patients who present within 1 hour may benefit from activated charcoal to reduce absorption of the drug.
Acetylcysteine should be given if:
there is a staggered overdose* or there is doubt over the time of paracetamol ingestion, regardless of the plasma paracetamol concentration; or patients who present 8-24 hours after ingestion of more than 150mg/kg of paracetamol (otherwise, wait for paracetamol levels to return)
Acetylcysteine is now infused over 1 hour (rather than the previous 15 minutes) to reduce the number of adverse effects. Acetylcysteine commonly causes an anaphylactoid reaction (non-IgE mediated mast cell release). Anaphylactoid reactions to IV acetylcysteine are generally treated by stopping the infusion, then restarting at a slower rate.
When to give acetylcysteine 24 hours after ingestion;
The patent is clearly jaundiced
The patient has hepatic tenderness
The ALT is above the upper limit of normal
The INR is greater than 1.3
The paracetamol concentration is detectable
Liver transplant criteria;
Arterial pH < 7.3, 24 hours after ingestion
or all of the following:
prothrombin time > 100 seconds
creatinine > 300 µmol/l
grade III or IV encephalopathy
Drug induced liver disease
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
Diclofenac
Diclofenac is now contraindicated with any form of cardiovascular disease
Tetracycline SE
associated with sensitivity to light
Ciprofloxacin
Ciprofloxacin is contraindicated in G6PD deficiency
Heparin
Unfractionated, ‘standard’ heparin or low molecular weight heparin (LMWH) eg. fondaparinux/enoxaparin. Both activate antithrombin III
Adverse effects of heparins include:
-bleeding
-thrombocytopenia (HIT)
-osteoporosis and an increased risk of fractures
-hyperkalaemia - this is thought to be caused by inhibition of aldosterone secretion
Unfractionated/Standard heparin
-IV
-Short acting
-Activates antithrombin III. Forms a complex that inhibits thrombin, factors Xa, IXa, Xia and XIIa
-Requires monitoring: APTT
-Useful in situations where there is a high risk of bleeding as anticoagulation can be terminated rapidly. Also useful in renal failure
LMWH
-S/C
-Long acting
-Activates antithrombin III. Forms a complex that inhibits factor Xa
-Routine monitoring not required (although Anti-Factor Xa can be used)
Heparin overdose may be reversed by protamine sulphate, although this only partially reverses the effect of LMWH.
Warfarin: management of high INR
INR 5.0-8.0
No bleeding
-Withhold 1 or 2 doses of warfarin
-Reduce subsequent maintenance dose
INR 5.0-8.0
Minor bleeding
-Stop warfarin
-Give intravenous vitamin K 1-3mg
-Restart when INR < 5.0
INR > 8.0
No bleeding
-Stop warfarin
-Give vitamin K 1-5mg by mouth, using the intravenous preparation orally
-Repeat dose of vitamin K if INR still too high after 24 hours
-Restart when INR < 5.0
INR > 8.0
Minor bleeding
-Stop warfarin
-Give intravenous vitamin K 1-3mg
-Repeat dose of vitamin K if INR still too high after 24 hours
Restart warfarin when INR < 5.0
Major bleeding (Any INR)
-Stop warfarin
-Give intravenous vitamin K 5mg
-Prothrombin complex concentrate - if not available then FFP*
SSRI and NSAID
Give a PPI
Beta blockers and acute heart failure
in acute heart failure with the presence of either a heart rate<50 beats/min, 2nd or 3rd-degree AV block, or shock, beta-blockers should be stopped.
Certain antiemetics to avoid in certain situations
Cyclizine is a H1-receptor antagonist that acts by blocking histamine receptors in the CTZ. It is safe to use in pregnancy. However, cyclizine can cause a drop in cardiac output and an increase in heart rate. For this reason, caution should be employed in patients with severe heart failure.
Dopamine antagonists, such as metoclopramide, are pro-kinetics and should therefore be avoided in intestinal obstruction. Dopamine antagonists should also be used with caution in patients with Parkinson’s disease.
DOAC’s/NOAC’s in Pregnancy
Contraindicated- use LMWH instead
IM Carboprost (uterine atony)
Avoid in asthmatics
Mirtazapine
Antidepressant that causes weight gain
Fluoxetine- antidepressant that causes weight loss
Adrenaline doses
anaphylaxis: 0.5ml 1:1,000 IM
cardiac arrest: 10ml 1:10,000 IV or 1ml of 1:1000 IV
Management of accidental injection- local infiltration of phentolamine
Problematic drinking management
disulfiram- unpleasant reaction. Don’t use in IHD/psychosis
acamprosate- reduces craving, known to be a weak antagonist of NMDA receptors
Allopurinol
works by inhibiting xanthine oxidase
Commencement of ULT is best delayed until inflammation has settled as ULT is better discussed when the patient is not in pain
urate-lowering therapy to all patients after their first attack of gout
adverse derm effects
interacts with- azathioprine, theophylline, cyclophosphamide
Alpha blockers and cataracts
Caution should be exercised in patients who are having cataract surgery due to the risk of intra-operative floppy iris syndrome
Amiodarone
Adverse effects of amiodarone use
thyroid dysfunction: both hypothyroidism and hyper-thyroidism
corneal deposits
pulmonary fibrosis/pneumonitis
liver fibrosis/hepatitis
peripheral neuropathy, myopathy
photosensitivity
‘slate-grey’ appearance
thrombophlebitis and injection site reactions
bradycardia
lengths QT interval
Important drug interactions of amiodarone include:
decreased metabolism of warfarin, therefore increased INR
increased digoxin levels
Aspirin
Aspirin works by blocking the action of both cyclooxygenase-1 and 2. (non reversible)
Cyclooxygenase is responsible for prostaglandin, prostacyclin and thromboxane 2 synthesis.
Beta blocker overdose
Management
if bradycardic then atropine
in resistant cases glucagon may be used
Haemodialysis is not effective in beta-blocker overdose
Dihydropyridines
Nifedipine, amlodipine, felodipine
Affects the peripheral vascular smooth muscle more than the myocardium and therefore do not result in worsening of heart failure but may therefore cause ankle swelling
SE’s- Flushing, headache, ankle swelling
Non-dihydropyridines can cause heart failure/bradycardia/hypotension (and constipation-verapamil)
Ciclosporin
nephrotoxicity
hepatotoxicity
fluid retention
hypertension
hyperkalaemia
hypertrichosis
gingival hyperplasia
tremor
impaired glucose tolerance
hyperlipidaemia
increased susceptibility to severe infection
Cocaine
cocaine blocks the uptake of dopamine, noradrenaline and serotonin
Many SE’s during toxicity but some to remember;
both tachycardia and bradycardia may occur
hypertension
QRS widening and QT prolongation
aortic dissection
ischaemic colitis
hyperthermia
metabolic acidosis
rhabdomyolysis
Mx- benzodiazpines (GTN for chest pain, sodium nitroprusside for HTN), no beta blockers
Diclofenac contraindications
ischaemic heart disease
peripheral arterial disease
cerebrovascular disease
congestive heart failure (New York Heart Association classification II-IV)
Digoxin and toxicity
Monitoring
digoxin level is not monitored routinely, except in suspected toxicity
if toxicity is suspected, digoxin concentrations should be measured within 8 to 12 hours of the last dose
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, ciclosporin. Also drugs which cause hypokalaemia e.g. thiazides and loop diuretics
Urticaria
aspirin
penicillins
NSAIDs
opiates
Drug-induced impaired glucose tolerance
thiazides, furosemide (less common)
steroids
tacrolimus, ciclosporin
interferon-alpha
nicotinic acid
antipsychotics
Beta-blockers cause a slight impairment of glucose tolerance. They should also be used with caution in diabetics as they can interfere with the metabolic and autonomic responses to hypoglycaemia
Drug-induced thrombocytopenia
quinine
abciximab
NSAIDs
diuretics: furosemide
antibiotics: penicillins, sulphonamides, rifampicin
anticonvulsants: carbamazepine, valproate
heparin
Drug-induced urinary retention
tricyclic antidepressants e.g. amitriptyline
anticholinergics e.g. antipsychotics, antihistamines
opioids
NSAIDs
disopyramide
Drugs causing lung fibrosis
amiodarone
cytotoxic agents: busulphan, bleomycin
anti-rheumatoid drugs: methotrexate, sulfasalazine
nitrofurantoin
ergot-derived dopamine receptor agonists (bromocriptine, cabergoline, pergolide)
Drugs causing ocular problems
steroids
amiodarone
indomethacin
ethambutol
amiodarone
metronidazole
chloroquine, quinine
Sildenafil
Drugs causing photosensitivity
thiazides
tetracyclines, sulphonamides, ciprofloxacin
amiodarone
NSAIDs e.g. piroxicam
psoralens
sulphonylureas
Ecstasy overdose
supportive
dantrolene may be used for hyperthermia if simple measures fail
Ethylene glycol toxicity
metabolic acidosis with high anion gap and high osmolar gap.
fomepizole, an inhibitor of alcohol dehydrogenase, is now used first-line in preference to ethanol
haemodialysis also has a role in refractory cases
Finasteride
Indications
benign prostatic hyperplasia
male-pattern baldness
Adverse effects
impotence
decrease libido
ejaculation disorders
gynaecomastia and breast tenderness
Finasteride causes decreased levels of serum prostate-specific antigen
Flecanide
Contraindications
post myocardial infarction
structural heart disease: e.g. heart failure
sinus node dysfunction; second-degree or greater AV block
atrial flutter
Adverse effects
negatively inotropic
bradycardia
proarrhythmic
oral paraesthesia
visual disturbances
Gentamicin
both peak (1 hour after administration) and trough levels (just before the next dose) are measured
Myasthenia gravis is a contraindication
Hypomagnesia
drugs
diuretics
proton pump inhibitors
total parenteral nutrition
diarrhoea
may occur with acute or chronic diarrhoea
alcohol
hypokalaemia
hypercalcaemia
Features may be similar to hypocalcaemia:
paraesthesia
tetany
seizures
arrhythmias
decreased PTH secretion → hypocalcaemia
ECG features similar to those of hypokalaemia
exacerbates digoxin toxicity
<0.4 mmol/L or tetany, arrhythmias, or seizures
intravenous magnesium
> 0.4 mmol/l
oral magnesium salts
diarrhoea can occur
Lithium toxicity
Toxicity may be precipitated by:
dehydration
renal failure
drugs: diuretics (especially thiazides), ACE inhibitors/angiotensin II receptor blockers, NSAIDs and metronidazole.
mild-moderate toxicity may respond to volume resuscitation with normal saline
haemodialysis may be needed in severe toxicity
Macrolides (erythromycin/clarithromycin/azithromycin)
Adverse effects
prolongation of the QT interval
gastrointestinal side-effects are common. Nausea is less common with clarithromycin than erythromycin
cholestatic jaundice: risk may be reduced if erythromycin stearate is used
P450 inhibitor (see below)
azithromycin is associated with hearing loss and tinnitus
Common interactions
statins should be stopped whilst taking a course of macrolides. Macrolides inhibit the cytochrome P450 isoenzyme CYP3A4 that metabolises statins. Taking macrolides concurrently with statins significantly increases the risk of myopathy and rhabdomyolysis.
Metformin
Contraindications
chronic kidney disease: NICE recommend that the dose should be reviewed if the creatinine is > 130 µmol/l (or eGFR < 45 ml/min) and stopped if the creatinine is > 150 µmol/l (or eGFR < 30 ml/min)
metformin may cause lactic acidosis if taken during a period where there is tissue hypoxia. Examples include a recent myocardial infarction, sepsis, acute kidney injury and severe dehydration
iodine-containing x-ray contrast media: examples include peripheral arterial angiography, coronary angiography, intravenous pyelography (IVP); there is an increasing risk of provoking renal impairment due to contrast nephropathy; metformin should be discontinued on the day of the procedure and for 48 hours thereafter
Starting metformin
metformin should be titrated up slowly to reduce the incidence of gastrointestinal side-effects
if patients develop unacceptable side-effects then modified-release metformin should be considered
Organophosphate insecticide poisoning
Features
Salivation
Lacrimation
Urination
Defecation/diarrhoea
cardiovascular: hypotension, bradycardia
also: small pupils, muscle fasciculation
Management
atropine
Overdose and poisoning page
Look at all the antidotes for all these poisons
CP450 System
CRAP GPs induce SICKFACES.com to inhibit their clinical reasoning skills
CRAP GPs can be used to easily remember common CYP450 inducers (reduced treatment efficacy)
Carbemazepines
Rifampicin
Alcohol
Phenytoin
Griseofulvin
Phenobarbitone
Sulphonylureas
The mnemonic SICKFACES.COM can be used to easily remember common CYP450 inhibitors (increased toxicity- builds up in blood)
Sodium valproate
Isoniazid
Cimetidine
Ketoconazole
Fluconazole
Alcohol & Grapefruit juice
Chloramphenicol
Erythromycin
Sulfonamides
Ciprofloxacin
Omeprazole
Metronidazole
Common Interactions
Exampled of drugs (substrates) that commonly interact with CYP450 enzyme inhibitors and inducers are; Warfarin the Combined Contraceptive Pill, Theophylline, Corticosteroids, Tricyclics, Pethidine, and Statins.
Sildenafil
Side-effects
visual disturbances
blue discolouration
non-arteritic anterior ischaemic neuropathy
nasal congestion
flushing
gastrointestinal side-effects
headache
priapism
nb- contraindicated by nitrates and nicorandil
Drugs to avoid in pregnancy
Antibiotics
tetracyclines
aminoglycosides
sulphonamides and trimethoprim
quinolones: the BNF advises to avoid due to arthropathy in some animal studies
Other drugs
ACE inhibitors, angiotensin II receptor antagonists
statins
warfarin
sulfonylureas
retinoids (including topical)
cytotoxic agents
The majority of antiepileptics including valproate, carbamazepine and phenytoin are known to be potentially harmful. The decision to stop such treatments however is difficult as uncontrolled epilepsy is also a risk
Quinolones (ciprofloxacin
levofloxacin)
Adverse effects
lower seizure threshold in patients with epilepsy
tendon damage (including rupture) - the risk is increased in patients also taking steroids
cartilage damage has been demonstrated in animal models and for this reason quinolones are generally avoided (but not necessarily contraindicated) in children
lengthens QT interval
Contraindications
Quinolones should generally be avoided in women who are pregnant or breastfeeding
avoid in G6PD
Salicylate (aspirin) overdose
salicylate overdose leads to a mixed respiratory alkalosis and metabolic acidosis. Early stimulation of the respiratory centre leads to a respiratory alkalosis whilst later the direct acid effects of salicylates (combined with acute renal failure) may lead to an acidosis
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
Side effects pages
look at these
Tamoxifen SE’s
menstrual disturbance: vaginal bleeding, amenorrhoea
hot flushes - 3% of patients stop taking tamoxifen due to climacteric side-effects
venous thromboembolism
endometrial cancer
Raloxefine lowers endometrial cancer risk
Teratogens page
look at this
Theopylline toxicity
Regardless of the time of presentation give activated charcoal to reduce absorption
Definitive treatment is with haemodialysis
Prescribing in people with asthma and COPD
A number of drugs should be used with caution in patients with asthma:
NSAIDs
beta-blockers
adenosine (usde verapamil instead)
Timing of prescription
The following medications are usually taken at night:
statins
amitriptyline
Frequency of prescriptions
The following medications are usually prescribed weekly in the UK:
bisphosphonates
methotrexate
Drugs and potassium
Decrease K
Thiazide diuretics
Loop diuretics
Acetazolamide
Increase K
ACE inhibitors
Angiotensin-2 receptor blockers
Spironolactone
Potassium sparing diuretics (amiloride, triamterene)
Potassium supplements (Sando-K, Slow-K)
Peripheral neuropathy
amiodarone
isoniazid
vincristine
nitrofurantoin
metronidazole
Ivabradine
Adverse effects
visual effects, particular luminous phenomena, are common
headache
bradycardia, heart block
Loop diuretics (furosemide and bumetanide)
Adverse effects
hypotension
hyponatraemia
hypokalaemia, hypomagnesaemia
hypochloraemic alkalosis
ototoxicity
hypocalcaemia
renal impairment (from dehydration + direct toxic effect)
hyperglycaemia (less common than with thiazides)
gout
Methotrexate
Adverse effects
mucositis
myelosuppression
pneumonitis
pulmonary fibrosis
liver fibrosis
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
Nicorandil
Adverse effects
headache
flushing
skin, mucosal and eye ulceration
gastrointestinal ulcers including anal ulceration
Contraindications
left ventricular failure
Nitrates
Side-effects
hypotension
tachycardia
headaches
flushing
Nitrate tolerance
many patients who take nitrates develop tolerance and experience reduced efficacy
the BNF advises that patients who develop tolerance should take the second dose of isosorbide mononitrate after 8 hours, rather than after 12 hours. This allows blood-nitrate levels to fall for 4 hours and maintains effectiveness
this effect is not seen in patients who take modified release isosorbide mononitrate
Phenytoin adverse effects
Acute
initially: dizziness, diplopia, nystagmus, slurred speech, ataxia
later: confusion, seizures
Chronic
common: gingival hyperplasia (secondary to increased expression of platelet derived growth factor, PDGF), hirsutism, coarsening of facial features, drowsiness
megaloblastic anaemia (secondary to altered folate metabolism)
peripheral neuropathy
enhanced vitamin D metabolism causing osteomalacia
lymphadenopathy
dyskinesia
Idiosyncratic
fever
rashes, including severe reactions such as toxic epidermal necrolysis
hepatitis
Dupuytren’s contracture*
aplastic anaemia
drug-induced lupus
Teratogenic
associated with cleft palate and congenital heart disease
Valproate
Adverse effects
teratogenic
P450 inhibitor
gastrointestinal: nausea
increased appetite and weight gain
alopecia: regrowth may be curly
ataxia
tremor
hepatotoxicity
pancreatitis
thrombocytopaenia
hyponatraemia
hyperammonemic encephalopathy:
Sulfonylureas
Common adverse effects
hypoglycaemic episodes (more common with long-acting preparations such as chlorpropamide)
weight gain
Rarer adverse effects
hyponatraemia secondary to syndrome of inappropriate ADH secretion
bone marrow suppression
hepatotoxicity (typically cholestatic)
peripheral neuropathy
Sulfonylureas should be avoided in breastfeeding and pregnancy.
Thiazide diuretics (bendroflumethiazide)
Common adverse effects
dehydration
postural hypotension
hyponatraemia, hypokalaemia, hypercalcaemia*
gout
impaired glucose tolerance
impotence
Rare adverse effects
thrombocytopaenia
agranulocytosis
photosensitivity rash
pancreatitis
Triptans
Contraindications
patients with a history of, or significant risk factors for, ischaemic heart disease or cerebrovascular disease
General factors that may potentiate warfarin
liver disease
P450 enzyme inhibitors (see below)
cranberry juice
drugs which displace warfarin from plasma albumin, e.g. NSAIDs
inhibit platelet function: NSAIDs
5-HT3 antagonists
5-HT3 antagonists are antiemetics used mainly in the management of chemotherapy-related nausea. They mainly act in the chemoreceptor trigger zone area of the medulla oblongata.
Examples
ondansetron
palonosetron
second-generation 5-HT3 antagonist
main advantage is reduced effect on the QT interval
Adverse effects
prolonged QT interval
constipation is common
ACE-I
Side-effects:
cough
occurs in around 15% of patients and may occur up to a year after starting treatment
thought to be due to increased bradykinin levels
angioedema: may occur up to a year after starting treatment
hyperkalaemia
first-dose hypotension: more common in patients taking diuretics
Cautions and contraindications
pregnancy and breastfeeding - avoid
renovascular disease - may result in renal impairment
aortic stenosis - may result in hypotension
hereditary of idiopathic angioedema
specialist advice should be sought before starting ACE inhibitors in patients with a potassium >= 5.0 mmol/L
Suxamethanium and the eye
contraindicated for patients with penetrating eye injuries or acute narrow angle glaucoma, as suxamethonium increases intra-ocular pressure
Drug Monitoring
See passmed page
Malignant hyperthermia
Malignant hyperthermia (MH) is a rare, serious side effect of volatile liquid anaesthetics (isoflurane, desflurane, sevoflurane), which cause all skeletal muscle to rapidly contract, including during a neuromuscular blockade. MH is a genetic disorder, manifesting due to calcium overload in the skeletal muscle causing sustained muscular contraction and rhabdomyolysis, resulting in excess anaerobic metabolism causing acidosis. End-tidal CO2 increases as a result, along with body temperature which causes diaphoresis (excess sweating).
Cardiac arrest due to opioid toxicity
400 microgram bolus of naloxone
Etomidate
Adrenal suppression
Suxamethonium
Good for rapid induction of anaesthesia
Can cause irreversible muscle twitching
Opioids in renal failure
Oxycodone
if renal impairment is more severe, alfentanil, buprenorphine and fentanyl are preferred
Antiemetics for certain situations
Raised ICP- cyclizine
Chemo-induced- ondansetron, haloperidol and levomepromazine
Reduced gastric motility- metoclopramide (not in obstruction however)
Vestibular- cyclizine
PD- domperidone
Drugs that can cause urinary retention
Opioids, tricyclic antidepressants, anticholinergics, and NSAIDs.
Domperidone
domperidone, another dopamine antagonist licensed for the
treatment of nausea, is safe to use for patients with Parkinson’s disease as it does not
cross the blood-brain barrier).
Combination antiplatelet and anticoagulant therapy
Secondary prevention of stable cardiovascular disease with an indication for an anticoagulant
normally in this situation, all patients are recommended to be prescribed an antiplatelet
if an indication for anticoagulant exists (for example atrial fibrillation) it is indicated that anticoagulant monotherapy is given without the addition of antiplatelets
Post-acute coronary syndrome/percutaneous coronary intervention
in these patients, there is a much stronger indication for antiplatelet therapy
generally patients are given triple therapy (2 antiplatelets + 1 anticoagulant) for 4 weeks-6 months after the event and dual therapy (1 antiplatelet + 1 anticoagulant) to complete 12 months
Vitamin D and bisphosphonates
vitamin D and calcium have to be corrected first before giving bisphosphanates
Hyoscine
respiratory secretions & bowel colic may be treated by hyoscine hydrobromide, hyoscine butylbromide, or glycopyrronium bromide
Hydrocortisone supplementation
Hydrocortisone supplementation is required prior to surgery for patients taking prednisolone
Carbon monoxide poisoning
Smokers may normally have carboxyhaemoglobin levels of up to 10%
methaemaglobin
Nitrates, including recreational nitrates such as amyl nitrite (‘poppers’) may cause methaemoglobinaemia
ciclosporin SE’s
everything is increased - fluid, BP, K+, hair, gums, glucose
General rules diabetes and surgery
patients treated with insulin who have good glycaemic control (HbA1c < 69 mmol/mol) and are undergoing minor procedures, can be managed during the operative period by adjustment of their usual insulin regimen
(surgery requiring a long fasting period of more than one missed meal) or whose diabetes is poorly controlled, will usually require a variable rate intravenous insulin infusion (VRIII)
Metformin and surgery
If taken once or twice a day - take
as normal
If taken three times per day, omit lunchtime dose
Sulfonylureas
If taken once daily in the morning - omit the dose that
day
If taken twice daily - omit the morning dose that day
If afternoon operation- omit both doses
DPP4-I and surgery
Take as normal
GLP-1 analogues
Take as normal
SGLT-2 inhibitors
Omit on the day of surgery
SGLT-2 inhibitors
Omit on the day of surgery
Once daily insulins eg. lantus and levemir
Reduce dose by 20%
Twice daily insulins eg. novomix and humulin
Halve the usual morning dose. Leave evening dose unchanged
amiloride
potassium sparring diuretic
Cytotoxic agents main SE’s
cyclophosphamide- bladder
doxorubicin- cardiomyopathy
methotrexate/5-fu- mucositis
vincristine/cisplatin- peripheral neuropathy
cisplatin- ototoxic, hypomagnesia
sedating antihistamine
Chlorphenamine
Cyproheptadine
Hydroxyzine
Promethazine
non sedating antihistamines
Cetirizine
Fexofenadine
Loratadine
Booster pneumococcal vaccine
Every 5 years to people with spleen issues/CKD
NB- given once only to others eg. cardioresp disease: COPD/asthma/CHF (no booster)
Pain relief in severe renal disease
eGFR <10- fentanyl or buprenophine
eGFR 10-50- oxycodone
