Medicines 13

Question 1

What are some key interactions regarding pseudoephedrine

Answer 1

Adrenergic neurone blockers – antagonises hypotensive effect of adrenergic neurone blockers - alpha blockers and beta blockers
Aluminium hydroxide – absorption of pseudoephedrine possibly increased by aluminium hydroxide – leave a gap
MAOIs – risk of hypertensive crisis when pseudoephedrine given with MAOIs, avoid pseudoephedrine for at least 2 weeks after stopping MAOIs
Antipsychotics – hypertensive effect of sympathomimetic antagonised by antipsychotics

Rasagiline – avoid concomitant use of sympathomimetic with Rasagiline (Rasagiline is a MAO-B inhibitor)

Question 2

What is the MOA of codiene and dihydrocodiene?

Answer 2

Codeine and dihydrocodeine

Very weak opioids
Metabolised in liver to produce small amounts of morphine (from codeine) or diamorphine (from dihydrocodeine)
These metabolites are stronger agonist of opioid µ receptors
10% Caucasians may find these drugs ineffective because they lack this metabolising enzyme

Question 3

What is the MOA of tramadol?

Answer 3

Tramadol

Synthetic analogue of codeine
Tramadol and its active metabolite are µ receptor agonists
It also acts as a serotonin and noradrenaline reuptake inhibitor

Question 4

What are some key cautions and contraindications in weak opioids ?

Answer 4

Cautions and contraindications; conditions

Caution in patients with significant respiratory disease – avoid in COPD
Reduce dose in renal and hepatic impairment and elderly
Tramadol lowers seizure threshold – avoid in epilepsy and do not use in uncontrolled epilepsy
Reduce dose in hypothyroidism
Caution in cardiac arrhythmias – codeine

Avoid codeine:
Acute ulcerative colitis
Antibiotic-associated colitis
Children under 18 years who undergo the removal of tonsils

Question 5

What medicine interactions can occur with weak opioids and in particular tramadol

Answer 5

Drugs:

Alcohol – enhanced hypotensive effect
Tricyclic antidepressants, benzodiazepines – sedative effects may be increased
Antihistamines – sedative effects increased
Cimetidine – metabolism of opioids inhibits – increased concentration
MAOIs – CNS excitation or depression – avoid use and for 2 weeks after stopping
SSRIs and Tricyclics lower seizure threshold – avoid use with tramadol
Tramadol interactions

SSRIs and Tricyclics – increase risk of CNS toxicity
Buprenorphine – opioid withdrawal when given together
Coumarins – enhances anticoagulant effects of coumarins
MAOIs – increased serotonin effects and increased risk of convulsions when tramadol given with MAOIs—some manufacturers advise avoid concomitant use and for 2 weeks after stopping MAOIs

Question 6

What are some key side effects of opioids?

Answer 6

Respiratory depression – reduces respiratory drive
Bradycardia, hypotension, feeling dizzy
Euphoria and detachment
Neurological depression in higher doses
Nausea and vomiting – by activating CTZ
Pupillary constriction – pinpoint pupils
Constipation – due to activation of µ receptors in small intestine = reducing smooth muscle tone
Itching – due to histamine release in the skin
Tolerance and dependence – withdrawal reaction

Question 7

What are some key points/counselling points to consider with opioids?

Answer 7

Look out for signs of breathlessness
Dose increase should be no more than 50% of previous dose
Do not stop treatment suddenly
Methadone solution is 2.5 times the strength of methadone linctus. Many preparations of methadone oral solution is licensed for drug addiction only but some are also licensed for severe pain
Fentanyl patches: apply on a dry hairless upper part of the body away from heat. Change every 72 hours.

Question 8

What are the common side effects of azathioprine as per BNF?

Answer 8

Bone marrow depression (dose-related); increased risk of infection; leucopenia; pancreatitis; thrombocytopenia

therefore BNF advises
Bone marrow suppression
Patients and their carers should be warned to report immediately any signs or symptoms of bone marrow suppression e.g. inexplicable bruising or bleeding, infection.

Question 9

What medications would be key to look out for with some one that has hepatic or renal impairment taking Mirabegron?

Answer 9

Strong CYP3A inhibitors such as clarithromycin, itraconazole, or ritonavir — avoid or reduce the dose of mirabegron in people with hepatic or renal impairment who are also taking one of these drugs. Plasma concentrations of mirabegron may be increased by concurrent use with strong CYP3A inhibitors.

Question 10

What cautions or contraindications are associated with digoxin?

Answer 10

Cautions and contraindications: Conditions;

Avoid in second degree heart block and complete heart block
Avoid in ventricular arrhythmias
Renal failure – reduce dose as digoxin is eliminated via kidneys
Hypokalaemia, hypomagnesaemia, hypercalaemia – increase digoxin toxicity
Caution in recent myocardial infarction

Question 11

What are some key medicine interactions to note with digoxin?

Answer 11

Loop and thiazide diuretic – increase digoxin toxicity due to hypokalaemia
Amiodarone – increase plasma concentrations of digoxin – halve dose of digoxin
CCB – increase plasma concentrations of digoxin
Diltiazem and verapamil – increase plasma concentration of digoxin and risk of AV block and bradycardia – reduce dose of digoxin
Spironolactone – increase plasma concentrations of digoxin
Quinine – increase plasma concentrations of digoxin
Itraconazole – increases concentration of digoxin
St john’s wort – reduces concentration of digoxin
Erythromycin and rifampicin – increase digoxin toxicity
Beta blockers – increased risk of AV block and bradycardia
NSAIDs – exacerbation of heart failure and reduced renal function

Question 12

What are the main uses with digoxin?

Answer 12

Atrial fibrillation/ flutter – to reduce ventricular rate (beta-blocker, Non-dihydropyridine CCBs more effective)
3rd line in severe heart failure

Question 13

What conditions can doxazosin be used to treat as per BNF

Answer 13

benign prostatic hyperplasia
Add -on for resistant hypertension

Question 14

What are some key counselling point associated with amiodorone?

Answer 14

Report any symptoms of breathlessness, persistent cough, jaundice, restlessness, weight loss, tiredness or weight gain.
Avoid drinking grapefruit juice as it can increase risk of side effects
Avoid sun exposure to skin even on a cloudy day and use plenty of suncream.
You will be started on a high dose, for one week only. Your dose will then be reduced over the following two weeks to a maintenance dose.

Question 15

What are some key things to monitor with amiodarone ?

Answer 15

Liver function, cardiac function, thyroid function, renal function and chest x-ray.
Liver and thyroid tests – every 6 months
Potassium levels - can cause QT prolongation

Question 16

What key drugs can amiodarone interact with?

Answer 16

Digoxin – increases concentrations of digoxin – reduce digoxin dose by half
Diltiazem and verapamil – increases concentration of these - Can increase bradycardia, AV block, heart failure with these 2

TCA – increased risk of ventricular arrhythmias – avoid

Beta blockers – increased risk of bradycardia, AV block and myocardial depression
Citalopram – risk of ventricular arrhythmias – avoid
Coumarins – amiodarone inhibits coumarin metabolism = enhanced anticoagulant effect
Diuretics; loops and thiazides = risk of amiodarone toxicity if hypokalaemia occurs
Grapefruit juice – plasma concentration of amiodarone increased
Haloperidol – increased risk of ventricular arrhythmias
Lithium – risk of ventricular arrhythmias, amiodarone can affect metabolism of lithium and both affect thyroid function – avoid
Phenytoin – amiodarone inhibits phenytoin metabolism – increased conc.
Simvastatin – increased risk of myopath

Question 17

What are some key side effects of amiodarone ?

Answer 17

Hypotension – during IV infusion
Lungs – pneumonitis
Heart – bradycardia, AV block
Liver – hepatitis – jaundice
Skin – photosensitivity, grey discolouration
Thyroid abnormalities – due to its iodine content

Has a very long half life and can take months to clear rom the body

Question 18

Why do you avoid aspirin in under 16 ?

Answer 18

Avoid under 16 years – causes Reye’s syndrome
Reye syndrome is a rapidly worsening brain disease

Question 19

What do you monitor with statins?

Answer 19

For primary prevention of CVD check lipid profile
Liver enzymes at 3 and 12 months
Signs of muscle symptoms

Question 20

Why were iron supplements dropped to recommended once daily dosing from 2-3?

Answer 20

Studies show administration of 200mg oral ferrous sulfate on alternative days result in
almost twice the amount of iron absorption as that from taking 100mg on consecutive days

• This means fewer pills, and perhaps less gastrointestinal side effects.

Question 21

Aside from the MHRA alerts what other side effects should people be aware of when taking sodium valproate?

Answer 21

Look out for warning signs:
Pancreatitis – abdominal pain, nausea, or vomiting

Blood or hepatic disorders

GI upset: nausea, gastric irritation, diarrhoea
Neurological and psychiatric: tremor, ataxia, behavioural disturbance
Thrombocytopenia
Increase in liver enzymes – monitor liver function until levels returned to normal
Hypersensitivity reactions:

Hair loss – regrowth will be curlier
Life threatening idiosyncratic SE: severe liver injury, pancreatitis, bone marrow failure and antiepileptic hypersensitivity syndrome

Question 22

What are the main uses of sodium valproate?

Answer 22

Main uses

Epilepsy – 1st choice for control of generalised or absence seizures and treatment option for focal seizures
Bipolar disorder – acute treatment of manic episodes and prophylaxis against recurrence

Question 23

What are the main cautions and contraindications with sodium valproate?

Answer 23

Cautions and contraindications; conditions

Avoid in women of child-bearing age
Avoid around time of conception
Avoid in first trimester of pregnancy 🡪 associated with greatest risk of foetal abnormalities:

Neural tube defects, craniofacial, cardiac and limb abnormalities and developmental delay

Avoid in hepatic impairment – hepatic failure may occur in 1st 6 months
Reduce dose in severe renal impairment
Discontinue treatment if pancreatitis symptoms develop

Question 24

What are the main uses of first generation antipsychotics?

Answer 24

Urgent treatment of psychomotor agitation that is causing dangerous or violent behaviour or to calm patients to allow assessment
Schizophrenia – when metabolic side effects of second generation are problematic
Bipolar disorder – in acute episodes of mania or hypomania
Nausea and vomiting – palliative care – haloperidol

Question 25

What are some key side effects of 1st generation antipsychotics?

Answer 25

Extrapyramidal effects – movement abnormalities:
Acute dystonic reactions – involuntary parkinsonian movements or muscle spasms
Akathisia – inner restlessness
Neuroleptic malignant syndrome – rigidity, confusion, autonomic dysregulation, pyrexia
Tardive dyskinesia – last effect occurring months- years later – pointless, involuntary, repetitive movements = lip smacking, may be disabling – may not stop after stopping treatment.
Drowsiness
Hypotension
QT interval prolongation = arrhythmias
Erectile dysfunction
Hyperprolactinemia = menstrual disturbance, galactorrhoea, breast pain
Hyperglycaemia
Photosensitisation
Purple pigmentation of body surfaces: skin, retina