High Risk Drugs Flashcards
Antibiotics
Anticoagulants
Chemotherapy
Insulin
Antidiabetics
Narrow-therapeutic drugs
NSAIDS
Methotrexate
Opiates
Parenteral drugs
Valproate
- Risk of suicidal thoughts
- Women of child-bearing age need to be on pregnancy prevention programme.
- Use of valproate in migraine and bipolar is contra-indicated in pregnant women.
- Consider Vitamin D supplements in long term immobilised patients, inadequate sun exposure or dietary calcium intake.
- Liver toxicity can occur. Patients told to monitor for signs and seek immediate medical attention. Withdrawl may be required.
- Pancreatitis - seek medical attention if symptoms develop. Discontinuation of treatment maybe required.
- In pregnancy dose should be divided or modified release preparation to be used to avoid peak plasma valproate. Dose should be below 1g, greater dose is increased risk of teratogenicity.
- Monitoring of FBC and LFT (Before and during the first 6 months).
Anti-hypertensives
Amiodarone
Loading dose
200mg TDS for 1 week, 200mg BD for 1 week then 200mg OD.
Side effects
1. Corneal micro-deposition
2. Thyroid function
3. Hepatotoxicity - treatment discontinued if severe liver abnormalities or signs of liver damage
4. Pulmonary toxicity - new progressive shortness of breath or cough = pneumonitis
5. Phototoxicity
Monitoring
- TFTs before then every 6 months
- LFTs before then every 6 months
- serum K - before
- chest x-ray - before
- with IV USE - ECG and resuscitation facilities should be available
Pregnancy
Use only if no alternatives
Possible neonatal goitre
Digoxin
- cardiac glycosides
- positive ionotrope and negative chronotrope
Dose
- Plasma concentration 0.8-1mcg
- dose of digoxin can be determined at ventricular rate at rest
- should not be allowed to fall <60bpm
- reduce dose by half if given with amiodarone, dronedarone or quinine
Toxicity
- toxicity ranges from 1.5-3mcg/L
- toxicity is increased with electrolyte disturbances like HYPOKALEAMIA, HYPOMAGNESEAMIA, HYPERCALCAEMIA and HYPOXIA.
- symptoms SICK AND SLOW
BRADYCARDIA, HEART BLOCK
NAUSEA, VOMITING, ABDOMINAL PAIN AND DIARRHOEA
YELLOW VISION
- If toxicity occurs …. Withdraw the digoxin, correct electrolyte abnormalities, atropine for bradycardia and lastly digoxin specific antibody fragment (DigiFab)
Antidote
- antidote - digoxin specific antibody fragments - Digifab
- atropine sulfate can also be used to reverse the bradyarrythmias and ventricular arrhythmias
Monitoring
- plasma concentration - 6 hours after the dose is given
- serum electrolytes
- renal function
Anti-psychotics
Side-effects
1. Extrapyramidal symptoms
Most common with first generation (haloperidol). Least common with second generation - aripiprazole, clozapine, Olanzapine and quetiapine.
- parkinsonism symptoms (bradykinesia and tremor)
- dystonia (uncontrolled muscle spasm)
- akathesia (restlessness)
- tardive dyskinesia (involuntary movement of lips, tongue, face and jaw)
- Hyperprolactinaemia
Both first and second generation. Most common drugs; amisulpride, sulpiride and risperidone. Least common Aripiprazole, clozapine and quetiapine.
Symptoms:
- sexual dysfunction
- reduced bone mineral density
- menstrual disturbances
- breast enlargement and galactorrhoea
- increased risk of breast cancer. - Sexual dysfunction
Most common with haloperidol, Olanzapine, risperidone.
Least common with Aripiprazole and quetiapine. - Cardiovascular side-effect
- tachycardia
- arrhythmias
- hypotension
- QT interval prolongation
Drugs with low tendency to prolong QT interval prolongation Aripiprazole, clozapine, Olanzapine, prochlorperazine, risperidone and sulphide. - Hypotension
Presents acutely during the initial dose titration. Slow dose titration can be used to minimise postural hypotension.
Drugs most likely to cause postural hypotension are clozepine and quetiapine. - Hyperglycaemia and diabetes
Schizophrenia is associated with insulin resistance and diabetes.
First generation haloperidol are least likely and of the second generation amisulpride and aripiprazole have the lowest risk of diabetes. - Weight gain
All antipsychotics cause weight gain. Mostly likely to cause weight gain are clozepine and Olanzapine. Least likely drugs to cause weight gain are amisulpride, aripiprazole, haloperidol. - Neuroleptic malignant syndrome
Can occur with all antipsychotics. Discontinue medication for 5 days or longer. Can use bromocriptine (dopamine d2 receptor agonist) or dantroline can be used to treat.
Symptoms
- hyperthermia
- fluctuating levels of consciousness
- muscle rigidity
- autonomic dysfunction with fever, tachycardia and labile BP.
- sweating.
Monitoring
1. Weight - before, weekly for 6 weeks, at 12 weeks, a 1 year, then yearly.
2. Fasting blood glucose, HBA1c and blood lipids - baseline, at 12 weeks, at 1 year then yearly.
3. Prolactin concentration - at baseline.
4. ECG - if history of cardiovascular disease.
5. Blood pressure - before, at 12 weeks, a 1 year then yearly.
6. Full blood count - before and then yearly
7. Urea and electrolyte - before and yearly
8. Liver function - before and then yearly.
Clozapine
Offered once at least 2 anti-psychotics are used for an adequate duration.
If symptoms do not respond to clozapine consider reasons why not responding (adherence to therapy), review diagnosis, check plasma clozapine concentration before adding another anti-psychotic. Allow 8-10 weeks to assess response.
Patients need to be registered with ‘clozapine patient monitoring service’
MHRA
- potential fatal risk of intestinal obstruction, faecal impaction and paralytic lieu’s. Seek immediate medical attention before taking the next dose is constipation occurs
- monitor blood concentration for toxicity.
Caution; further info
- Agranulocytosis - leucocytes and differential blood should be normal before starting
- myocarditis and cardiomyopathy - fatal myocarditis most commonly in the first 2 months.
- intestinal obstruction- caution in pts on other medication that increase risk of constipation. Any constipation needs to be treated.
Side-effects
- hyper-salivation associated with clozepine can be treated with hyoscine hydrobromide.
Monitoring
- FBC
- blood lipids and weight
- fasting blood glucose
Treatment cessation
- withdraw the dose over 1-2 weeks
