Medicines 20 Flashcards
What key counselling points are there with SSRIs?
Treatment should improve symptoms after a few weeks
May need psychological therapy – longer term benefits
Carry on with drug treatment for at least 6 months after you feel better to stop the depression from coming back
Do not stop suddenly as this may cause stomach upset, flu-like withdrawal symptoms and sleepiness
Reduce dose slowly over 4 weeks to stop
What are the key side effects with amitriptylline?
Side effects
Block antimuscarinic receptors:
Dry mouth
Constipation
Urinary retention
Blurred vision
Drowsiness
Block H1 and α1 receptors:
Sedation
Hypotension
Cardiac effects:
Arrhythmias
ECG changes = prolongation of QT and QRS intervals
Brain:
Convulsions
Hallucinations
Mania
Blockade of dopamine receptors:
Breast changes
Sexual dysfunction
Extrapyramidal symptoms: tremor, dyskinesia
What does sudden withdrawal from TCAs cause?
GI upset, neurological and influenza-like symptoms, sleep disturbance
What key counselling points are there with TCAs like Amitriptyline ?
Counselling
Depression – start with 75mg
Neuropathic pain – start with 10mg at night
Side effect
Symptoms will improve over a few weeks
May need psychological therapy – long-term benefits
Carry on treatment for at least 6 months after you feel better to stop depression from returning
Do not stop suddenly – causes flu-like withdrawal symptoms and sleepiness
Reduce dose slowly over 4 weeks to stop
What cautions are there with TCAs like amitriptyline ?
Elderly – use low initial dose
CVD
Epilepsy
Constipation
Prostatic hypertrophy
Diabetes
Hyperthyroidism – risk of arrhythmias
Raised intraocular pressure – may be worsened by antimuscarinic
Contraindicated during manic phase of bipolar disorder, heart block and immediate recovery period after MI
Name some TCAs
Clomipramine, imipramine, doxepin, Amitriptylline
What is Hypromellose 1st line treatment for ?
1st line for dry eye conditions including keratoconjunctivitis sicca (Dry Eyes) and sjӧgren’s syndrome.
Common symptoms of Sjögren’s syndrome include:
dry eyes
a dry mouth
aching muscles and joints
extreme tiredness
What key counselling points are there to note with Hypromellose eye drops?
Apply when required
If your vision becomes blurred for a short while after using the drops, do not drive until you can see clearly again.
If you are using any other eye drops or ointments, leave about ten minutes between applying each one. It is usually recommended that you use hypromellose last. This is so that the drops stay in contact with your eye and lubricate it for as long as possible.
Do not wear soft contact lenses while you are using the drops unless your doctor or pharmacist has advised you otherwise. This is because there is a preservative in many of the brands of Hypromellose eye drops which can affect soft contact lenses.
What are some key side effects of systemic corticosteroids?
Immunosuppression – increases risk of infection
Diabetes mellitus
Osteoporosis
Muscle weakness
Skin thinning with easy bruising
Gastritis
Mood and behavioural changes: insomnia, confusion, psychosis, suicidal ideas
Hypertension – result from mineralocorticoid
Hypokalaemia – result from mineralocorticoid
Oedema – result from mineralocorticoid
Suppresses pituitary ACTH secretion switching off stimulus for normal adrenal cortisol production = adrenal atrophy 🡪 if steroid withdrawn suddenly = Addisonian crisis with cardiovascular collapse
What key counselling points need to be given with methotrexate?
Patients and their carers should be warned to report immediately the onset of any feature of blood disorders (e.g. sore throat, bruising, and mouth ulcers), liver toxicity (e.g. nausea, vomiting, abdominal discomfort and dark urine), and respiratory effects (e.g. shortness of breath).
Patients should be advised to avoid self-medication with over-the-counter aspirin or ibuprofen.
Patients should be counselled on the dose, treatment booklet, and the use of NSAIDs.
TAKE ONCE A WEEK on the same day each week
Take folic acid on a different day to methotrexate also one a week
Use effective contraception
What monitoring is required with methotrexate?
Exclude pregnancy before treatment
Monitor full blood count and renal and liver function tests before starting treatment
In view of reports of blood dyscrasias (including fatalities) and liver cirrhosis with low-dose methotrexate patients should:
have full blood count and renal and liver function tests repeated every 1–2 weeks until therapy stabilised, thereafter patients should be monitored every 2–3 months.
be advised to report all symptoms and signs suggestive of infection, especially sore throat
Local protocols for frequency of monitoring may vary.
Treatment with folinic acid (as calcium folinate) may be required in acute toxicity.
What are key cautions and contraindications with methotrexate?
Cautions and contraindications; conditions
Teratogenic = avoid in pregnancy
Use contraception men and women for up to 3 months after stopping
Severe renal impairment – contraindicated
Reduce dose in renal impairment = risk of nephrotoxicity at high doses
Abnormal liver function – avoid
Contraindicated in immunodeficiency
Avoid in severe blood disorders
Blood count
Bone marrow suppression can occur abruptly; factors likely to increase toxicity include advanced age, renal impairment, and concomitant use with another anti-folate drug (e.g. trimethoprim). A clinically significant drop in white cell count or platelet count calls for immediate withdrawal of methotrexate and introduction of supportive therapy.
Symptoms: sore throat, bruising, mouth ulcers, fever, rash
Gastro-intestinal toxicity
Withdraw treatment if stomatitis develops—may be the first sign of gastro-intestinal toxicity.
Symptoms: stomatitis
Liver toxicity
Liver cirrhosis reported. Treatment should not be started or should be discontinued if any abnormality of liver function tests or liver biopsy is present or develops during therapy. Abnormalities can return to normal within 2 weeks after which treatment may be recommenced if judged appropriate.
SYMPTOMS: jaundice, nausea, vomiting, diarrhoea, dark urine
Pulmonary toxicity
Pulmonary toxicity may be a special problem in rheumatoid arthritis (patient to seek medical attention if dyspnoea, cough or fever); monitor for symptoms at each visit—discontinue if pneumonitis is suspected.
Symptoms: dyspnoea, cough
What are the main indications of Methotrexate?
DMARD – Rheumatoid arthritis
Chemotherapy for cancer: leukaemia, lymphoma, solid tumours
Treatment of severe psoriasis (incl. psoriasis arthritis) resistant to other therapies
What are some key side effects of methotrexate?
Mucosal damage: sore throat, GI Upset
Bone marrow suppression: neutropenia and risk of infection: sore throat, fever
Hypersensitivity reactions: cutaneous reactions, hepatitis, pneumonitis
Hepatic cirrhosis and pulmonary fibrosis- after long-term use
ONCE WEEKLY
Overdose:
Renal impairment
Hepatotoxicity
Neurological effects: headache, seizure, coma
Treatment of overdose is with folic acid to save healthy cells and hydration and urinary alkalinisation to enhance methotrexate excretion
What is lactic acidosis, what are symptoms of lactic acidosis and what is the treatment?
Lactic acidosis is a life threatening condition characterised by elevated lactate levels and low PH.
Report lactic acidosis SE: vomiting, stomach-ache, muscle cramps, difficulty breathing, tiredness
Treatment varies based off the cause, however if metformin causes it, stop metformin and consider dialysis.
What monitoring is required with metformin treatment?
Renal function before treatment and at least annually (at least twice a year in patients with additional risk factors for renal impairment, or if deterioration suspected).
Glycosylated HbA1c
What drugs interact with metformin?
ACE inhibitors – hypoglycaemic effect enhanced
Alcohol – increased risk of lactic acidosis
Cimetidine – excretion of metformin reduced by cimetidine (increased plasma concentration)
MAOIs – hypoglycaemic effect of metformin enhanced
Beta blockers – warning signs of hypoglycaemia (such as tremor) with antidiabetics may be masked when given with beta-blockers
Corticosteroids – hypoglycaemic effect of antidiabetics antagonised by corticosteroids
Diuretics, oestrogens, progestogens – hypoglycaemic effect of antidiabetics antagonised
NSAIDs – use with caution can impair renal function – monitor
What cautions and contraindications?
Contraindication in severe renal impairment
Moderate renal impairment – reduce dose
Acute kidney injury – withhold treatment = e.g. in sepsis, shock, dehydration
Severe tissue hypoxia – cardiac, respiratory failure or MI – withhold
Hepatic impairment – caution = clearance of excess lactate may be impaired – lactic acidosis
Acute alcohol intoxication – withhold treatment – may precipitate lactic acidosis
Caution in chronic alcohol overdose – increased risk of hypoglycaemia
Contraindicated in ketoacidosis
Contraindicated in iodine-containing X-ray contrast media – IV iodinated contrast agents can cause renal failure which can increase risk of lactic acidosis with metformin 🡪 Suspend metformin prior to the test; restart no earlier than 48 hours after the test if renal function has returned to baseline.
What are the main indications for phenytoin?
Control seizures in status epilepticus where benzodiazepines are ineffective
Reduce frequency of generalised or focal seizures in epilepsy but valproate, lamotrigine, levetiracetam are preferred because they have less SE
What are the key side effects of phenytoin?
With long term therapy: Change in appearance – coarse skin, acne, hirsutism, gum hypertrophy
Dose related neurological effects: cerebellar toxicity – ataxia, poor coordination
Impaired cognition or consciousness
Haematological disorders
Osteomalacia – bone pain and muscle weakness – by inducing folic acid and vitamin D metabolism
Hypersensitivity reactions: skin rash to rare antiepileptic hypersensitivity syndrome
Toxicity:
Death through cardiovascular collapse and respiratory depression
What are the cautions and contraindications with phenytoin?
Low therapeutic index
Hepatic impairment – reduce dose
Pregnancy – craniofacial abnormalities and reduce IQ – avoid pregnancy
Caution with heart failure, hypotension, respiratory depression in IV use
Consider vitamin D therapy for those immobilised for long periods
Discontinue in hepatotoxicity and rash
What monitoring is required with Phenytoin?
Pre-monitoring: HLAB* 1502 allele in individuals of Han Chinese or Thai origin—avoid unless essential (increased risk of Stevens- Johnson syndrome)
Usual total plasma-phenytoin concentration for optimum response is 10–20 mg/litre (or 40–80 micromol/ litre).
In pregnancy, the elderly, and certain disease states where protein binding may be reduced, careful interpretation of total plasma-phenytoin concentration is necessary; it may be more appropriate to measure free plasma-phenytoin concentration.
In children: Therapeutic plasma-phenytoin concentrations are reduced in the first 3 months of life because of reduced protein binding.
Trough plasma concentration for optimum response: neonate–3 months, 6–15 mg/litre (25–60 micromol/ litre); child 3 months–18 years, 10–20 mg/litre (40–80 micromol/litre).
Manufacturer recommends blood counts (but evidence of practical value uncertain).
With intravenous use: Monitor ECG and blood pressure
Serum concentration
ECG and blood pressure with IV use
Liver function
Full blood count
Serum folate
Vitamin D
What key counselling points are required with Phenytoin?
Monitor plasma concentration of phenytoin when switching between formulations
Stick to same brand
Take with or after food
Report signs of skin rashes, bruising, infection
Avoid pregnancy need suitable contraception
Do not drive unless seizure free for 12 months
Will need to have regular blood tests
What are the key side effects of zopiclone?
Side effects
Daytime sleepiness – can affect driving
Rebound insomnia – when drugs are stopped
CNS effects: headache, confusion, nightmares, amnesia
Taste disturbance
Dependence – longer than 4 weeks = withdrawal symptoms – headaches, muscle pains, anxiety
What are the main indications of phenytoin?
Insomnia (short-term use)
Insomnia (short-term use) in patients with chronic pulmonary insufficiency
