Contra-Indications and Interactions Flashcards Preview

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Flashcards in Contra-Indications and Interactions Deck (58):
1

Antacids

Can reduce serum concentration of ACEi's, some Abx, digoxin, levothyroxine and PPI's

2

H2 antagonists

Reduce dose in CKD and can disguise symptoms of gastric cancer

3

PPI

Reduces effect of clopidogrel
Can disguise symptoms of gastric cancer and can increase risk of osteoporotic #

4

Loperamide

Avoid in acute UC/bloody diarrhoea and in possibility of C-diff

5

Laxatives

Do not use in obstruction

6

Aminosalicylate

Don't use in children < 2 or in renal impairment
Have pH resistant coating so affected by gastric pH modifying drugs (PPI)

7

Antiemetics

Risk of side effects increased when prescribed with antipsychotics

8

Loop Diuretics

Effects drugs that are renally excreted
Contraindicated in severe hypovolaemia/dehydration and caution in hepatic encephalopathy

9

Thiazide diuretics

Avoid in hypokalaemia/natraemia
Can precipitate acute gout attacks - increases uric acid levels
Effectiveness reduced by NSAIDs

10

Potassium Sparing Diuretics

Contraindicated in severe renal impairment, hyperkalaemia, addisons and pregnant women
Caution when using other K+ elevating drugs - ACE/ARB

11

Beta Blockers

Do not use in heart block, reduce dose in hepatic failure and dont use with non-dihydropyridine Ca blockers

12

Calcium Blockers

Caution in those with poor LV function, avoid in AV node conduction delay and unstable angina
Do not use non-dihy...... with B-blockers

13

ACE inhibitors/ AT1 Blockers

Avoid in those with Renal Artery Stenosis and pregnancy/ breastfeeding
Low doses in CKD
Avoid using with other K+ elevating drugs and risk of renal failure increased when used with NSAIDs

14

Nitrates

Contraindicated in severe aortic stenosis and if hemodynamically unstable

15

Cardiac Glycosides

Contraindicated in 2nd degree hear block
Do not use if risk of ventricular arrythmias, reduce dose in renal failure
Duiretics, amiodarone, Ca blockers and quinine can all increase risk of toxicity

16

Amiodarone

Only use when risk/benefits are balances as can be dangerous particularly in severe hypotension, heart block and active thyroid disease
Increases plasma levels of digoxin, diltiazem and verapamil

17

Aspirin

Not used in < 16yrs due to Reye's syndrome
Avoided in 3rd trimester of pregnancy
Caution in peptic ulceration and can cause acute attack of gout

18

Clopidogrel

Caution in renal/hepatic impairment
CP450 metabolised

19

Heparin/NOACs

Use in caution with other anticoagulants

20

Warfarin

Do not give in 1st trimester of pregnancy
Low therapeutic dose and CP450 metabolised

21

Statins

Caution in hepatic and renal impairment and pregnant/breasfeeding women

22

Beta-2-agonists

B-blockers reduce effectiveness

23

Anticholinergics

Caution in those at risk of Angle Closure Glaucoma as can cause rise in IOP

24

Corticosteoids

Use with NSAIDs increases risk of peptic ulceration + GI bleeding
Enhances hypokalaemia in those taking B2 agonists
CP450 metabolised

25

Theophylline

Contraindicated in porphyria
Smoking and alcohol increase clearance
CP450 metabolised

26

O2

Can disturb fine balance between hypoxia and hypercapnia in those with T2 resp failure - leading to rise in blood CO2

27

Insulin

Increased risk of hypo in renal impairment

28

Sulphonylureas

Reduce dose in hepatic impairment
Risk of hypo increased when used with other anti-diabetic drugs
Efficacy reduced by prednisolone, thiazides and loop diuretics as increase blood glucose

29

Biguanides

Contraindicated in severe renal impairment, caution in hepatic impairment
Withhold in acute alcohol intoxication and caution in chronic alcohol
Withhold for 48yrs post IV contrast

30

Thyroxine

In hypopituitarism, must administer corticosteroids first to avoid addisonian crisis
GI absorption reduced by antacids, calcium and iron salts

31

Carbimazole

Contraindicated in haematological/hepatic condition
Vit K antagonist so can enhance anticoagulative effects

32

Bisphosphonates

Avoid in severe renal impairment, hypocalcaemia and upper GI disorders
Absorption reduced with antacids, calcium and iron salts

33

Mineralocorticoids

Contraindicated in systemic infections, myasthenia gravis, increased eye pressure, cataracts, hypertension,
Caution when used with theophylline, loop and thiazide diuretics as all reduce K+

34

Penicillin

Reduce dose in severe renal impaiment
They reduce renal excretion of methotrexate and enhance warfarin effect

35

Cephalosporins

Caution in epilepsy and reduce dose in renal impairment.
Enhances effect of warfarin and can increase nephrotoxicity of aminoglycosides

36

Trimethoprim

Contraindicated in 1st trimester of pregnancy - foetal abnormalities
Used in caution in folate deficiency and reduce dose in renal impairment

37

Nitrofurantoin

Do not use in near term pregnancy/ babies < 3months
Contraindicated in patients with renal impairment

38

Tetracyclines

Dont use in pregnancy, breastfeeding, < 12 yrs or in renal impairment
Do not give within 2 hrs of iron, antacids or calcum as prevent absoption

39

Aminoglycosides

Avoid in myasthenia Gravis
Ototoxicity more likely if used with loop diuretics or vancomycin
Nephrotoxicity more likely if used with cyclosporin or vancomycin

40

Macrolides

Caution in renal/hepatic impairment
CP450 inhibitor

41

Quinolones

Calcium and antacids reduce absorption
CP450 inhibitor
Use with NSAIDs increases risk of seizures and use with prednisolone increase risk of tendon rupture

42

Metronidazole

CP450 metabolised
Inhibits acetaldehyde dehydrogenase which clears alcohol metabolites so no alcohol to be drunk

43

Glycopeptides

Dose adjustement in elderly and renal impairment
Increased risk of toxicity when prescribed with aminoglycosides, loop diuretics or ciclosporins

44

NSAIDs

Aspirin and corticosteroids increase risk of GI ulceration
Anticoagulants and SSRI's increase risk of bleeding
ACEi's and diuretics increase risk of renal impairment
Reduce efficacy of antihypertensives and duiretics

45

Codeine

Caution in sever respiratory disease, reduce dose in renal/hepatic impairment and the elderly
Do not use with other sedating drugs

46

Morphine

Reduce dose in hepatice failure and renal impairment and elderly
Do not give in resp failure or biliary colic

47

Paracetamol

Overdose can lead to liver failure due to saturation of pathway leading to build up of NAPQI

48

Xanthine-Oxidase Inhibitors

Reduce dose in severe hepatic/renal impairment
Reduces efficacy of mercaptopurine + azathioprine as require xanthine oxidase for metabolism
Use with amoxicillin increase risk of rash
Use with ACEi's and thiazides increase risk of hypersensitivity

49

Alpha Blockers

Contraindicated if already postural hypotension

50

5-alpha-reductase inhibitors

Do not use in pregnancy (or even come into contact with) as can cause abnormal development of male external genitalia

51

L-dopa

Do not use with antipsychotics or metoclopramide as effects contradictory

52

Phenytoin

Reduce dose in hepatic impairment
In utero exposure associated with craniofacial abnormalities and reduced IQ

53

Carbamazepine

In utero exposure associated with neural tube defects, cardiac and urinary abnormalities and cleft palate
Contraindicated in previous Antiepileptic Hypersensitivity syndrome

54

Sodium Valproate

Avoid in women of childbearing age and in 1st trimester as related to foetal abnormalities
Avoid in severe hepatic/ renal abnormalities
Inhibits CP450

55

Tricyclics

Caution in elderly, those at risk of CV disease and epilepsy and those with constipation, prostatic hypertrophy or raised IOP

56

SSRI's

Dose reduction in hepatic impairment
Gastroprotection needed if also taking NSAIDs
Do not prescribe with other drugs that prolong QT interval

57

Benzodiazepines

Reduce dose in elderly
Avoid in significant resp/neuro impairment
Avoid in liver failure

58

Acetylcholinesterase Inhibitors

Do not use whilst driving, breastfeeding or pregnant
Itraconazole, erythromycin and fluoxetine inhibit metabolism
Can interfere with anticholinergic medications such as atropine, amitriptyline and codeine