Pharmacology Flashcards
Sildenafil
Uses:
✓ Erectile dysfunction
✓ Pulmonary hypertension
✓ Treatment of digital ulcer -unlicensed use.
Contraindications:
✓ Hereditary degenerative retinal disorders e.g. Retinitis pigmentosis; h/o of non-arteritic anterior ischaemic optic neuropathy.
✓ CVS: Recent unstable angina, or recent history of Stroke or Myocardial Infarction
✓ When used in pulmonary arterial hypertension - co-existing Sickle cell anaemia is a contraindication.
Common side effects - alopecia, dizziness, headaches, blue vision, and cough.
Controlled Drugs
3 classes on basis of how harmful the drug is when misused.
Buprenorphine is a class C Controlled drug. Often used in transdermal form to help control chronic cancer pain.The
✓ Misuse of Drugs Act 1971 as amended prohibits certain activities in relation to ‘Controlled Drugs’, in particular their manufacture, supply, and possession (except where permitted by the 2001 Regulations or under licence from the Secretary of State).
✓ The Misuse of Drugs (Safe Custody) Regulations 1973 as amended details the storage and safe custody requirements for Controlled Drugs.
Drug induced renal stones
Acetazolamide
Allopurinol
Ascorbic acid
Laxatives
Lithium Toxicity
Narrow therapeutic/toxicity ratio. Check levels 12 hrs post dose (normal 0.4–1 mmol/l)
Toxicity features: vomiting, diarrhoea, visual problems, muscles weakness, fine tremor progressing to coarse tremor, polyuria, confusion, drowsiness and restlessness.
✓ Severe cases -seizures, cardiac arrhythmias, renal failure, coma, sudden death can occur.
✓ toxicity can be secondary overdose or reduced drug excretion with chronic t/t leading to worsening renal function and drug interactions
✓ Various ECG abnormalities - T wave inversion, PR prolongation, ventricular tachyarrhythmias.
✓ Side effects: abdominal pain, metallic taste, weight gain, fine tremor and nausea.
Monitoring in prescribing - 1
MONITORING REQUIREMENTS
ACEi and A2RB: U&E before starting, repeat 2/52 after initiation, 12/12 U&E
Digoxin: Renal function and electrolytes before starting; Digoxin level in long term
Diuretics: U&E before starting, repeat 2/52 after initiation. 12/12 U&E
Glitazones: LFT before starting therapy and 12/12
Statins: LFT before starting therapy, 3/12 and 12/12 LFT after starting
Amiodarone: 6/12 TFT and LFT
Azathioprine: 3/12 FBC
Carbimazole: 3/12 TFT and then 6/12 if stable over 1 year t
Levothyroxine: 12/12 TFT
Lithium: weekly lithium levels after starting or dose change, then 3/12 in older people or those on drugs that interact for 1st year, and then 6/12 TFT, U&E and bone profile
Methotrexate: 3/12 LFT, 6/12 U&E
Sulfasalazine : 3/12 FBC and LFT for first year, 6/12 FBC and LFT in second year. No further monitoring if stable
Theophylline: theophylline level if toxicity suspected
Sodium Valproate:weight, BMI, FBC & LFT on starting then, every 3/12 for first 6 months, then 6/12 then annually
Warfarin: 12/52 INR
Antipsychotics: weight weekly for the first 6 weeks, then at 12 weeks, at 1 year and then annually (plotted on a chart), waist circumference annually (plotted on a chart),
pulse and blood pressure at 12 weeks, at 1 year and then annually, fasting blood glucose or HbA1c, and blood lipid levels at 12 weeks, at 1 year and then annually
Errors in Prescribing
Drugs contraindicated in Pregnancy
Drugs causing Pulmonary Fibrosis
Cytotoxic - methotrexate, cyclophosphamide, busulphan, bleomycin
Antibio
Methylphenidate
Given for ADHD
Common side-effects - abdominal pain, nausea, dyspepsia, anorexia, stunts growth and reduced weight gain.
Advisable to monitor growth during treatment Height & Weight
Paracetamol poisoning
King’s College Hospital criteria - identifies patients with severe paracetamol hepatotoxicity whose short-term prognosis is so poor that supra-urgent liver transplantation is indicated.
- Transplantation - when arterial pH <7.3 after rehydration.
- Paracetamol overdose + abnormal coagulation + renal failure/ confusion - discussion with a specialist hepatology service.
- Reduced Glasgow coma scale (GCS), hypoglycaemia and persistently elevated lactate (>4 mmol/L) - referral to a liver transplant unit.
STEROIDS: Diminishing glucocorticoid and increasing mineralocorticoid activity
- Betamethasone, Dexamethasone
- Prednisolone
- Hydrocortisone
- Fludrocortisone
Drugs causing Hypertension as side effect
- corticosteroids
- ciclosporin
- combined oral contraceptive pill
3 C
Drugs causing Fluid Retention
- pioglitazone
- corticosteroids
- ciclosporin
P_C_C
Hyponatraemia
sulfonylureas
loop diuretics
thiazides
carbamazepine
sodium valproate
Drugs causing hyperlipdaemia
Steroids
Isotretinoin
