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
Drugs causing peripheral neuropathy
amiodarone
isoniazid
metronidazole
nitrofurantoin
phenytoin
Drugs causing Gynaecomastia
Spironolactone
Cimetidine
Finasteride
Cannabis
Digoxin
GnRH analogues
Estrogens
Rarely - Tricyclic antidepressants, Isoniazid, Calcium Channel Blockers, Heroin, Busulfan, Methydopa
Drugs causing Hypercalcaemia
- Thiazide diuretics
- Lithium
- Teriparatide
- Abaloparatide
- Excessive vitamin A
- Theophylline toxicity
Monitoring on Testosterone therapy
- 3-monthly haematocrit checks in the first year of treatment.
- Testosterone & haematocrit levels tested annually.
P450 inducers
Mnemonic: CRAP GPS
Carbamazepine
Rifampicin
Alcohol (chronic use)
Phenobarbitone
Griseofulvin
Phenytoin
Smoking
St John’s wort
P450 Inhibitors
Mnemonic: SICKFACES.COM
Sodium valproate
Isoniazid
Ciprofloxacin
Ketoconazole
Fluconazole
Alcohol (acute) & Grapefruit juice
Amiodarone
Allopurinol
Cimetidine
Erythromycin
Sulfonamides
Chloramphenicol
Omeprazole
Metronidazole
Ritonavir
Peripheral Neuropathy (side effect)
nitrofurantoin
isoniazid
amiodarone
metronidazole
phenytoin
Photosensitivity (side effect)
tetracyclines
isotretinoin
amiodarone
Oxybutinin - Anti-muscarinic
Use:
- Urge incontinence, neurogenic bladder instability and nocturnal enuresis associated with overactive bladder
- severe ulcerative colitis or toxic megacolon
Caution: Liver/ renal impairment
Contraindications: urinary retention, bladder outflow obstruction, myasthenia gravis, gastro-intestinal obstruction and atony, and severe ulcerative colitis or toxic megacolon.
BNF. Oxybutynin.
Prednisolone dose for acute asthma in children
<2 years: 10 mg
2-5 years: 20 mg
>5 years: 30 mg
Prevalence of prescribing monitoring error in primary care
1 in 20 (5%)
Drug Monitoring -2
Carbimazole: FBC + LFT prior to starting but repeat testing if clinically indicated. 3/12 TFT
Testosterone: testosterone + haematocrit levels 12/12, with 3/12 haematocrit checks in 1st year .
Drug induced urticaria - Causes
Angiotensin-converting enzyme inhibitors (ACEIs)*
Antibiotics: penicillins, cephalosporins, macrolides (erythromycin), aminoglycosides, tetracyclines, sulphonamides, vancomycin, fluoroquinolones
Anticoagulants: low molecular weight heparin, protamine sulfate
Anticonvulsants
Oral antifungal agents: fluconazole, ketoconazole, griseofulvin
Antineoplastic agents: alkylating agents, taxanes, methotrexate
Betadine (povidone-iodine)
Bisphosphonates
Dextrans
Dextromethorphan
Enzymes: trypsin, streptokinase, chymopapain
Hydantoins
Hydralazine
Mannitol
Muscle relaxants: atracurium, vecuronium, succinylcholine, curare
NSAIDS: ibuprofen, naproxen, diclofenac
Opioids: morphine, codeine, meperidine, fentanyl Paracetamol
Polypeptide hormones: insulin, corticotrophin, vasopressin
Progesterone
Quinidine
Radiographic contrast agents*
Salicylates* including aspirin
Sorbitol complexes
Corticosteroids
Thrombolytics: alteplase, urokinase
Vaccines
Drug causes of Steven Johnson syndrome
Abacavir
Acetominophen
Allopurinol
Antibiotics*
Anticonvulsants*
Antifungals*
Antivirals*
Atenolol
Azathioprine*
Beta-lactam antibiotics*
Captopril
Carbamazepine
Cephalosporins
Clomipramine
Dapsone*
Diltiazem
Gold salts*
Ibuprofen
Imidazole antifungals, eg ketoconazole,* itraconazole,* fluconazole*
Isoniazid
Lamotrigine
Mexiletine
Minocycline*
Naproxen
Nevirapine (non-nucleoside reverse-transcriptase inhibitor)
Nonsteroidal anti-inflammatory drugs (NSAIDs) (oxicam type mainly)*
Paracetamol
Penicillins*
Phenobarbitone
Phenytoin
Sulfasalazine*
Sulfonamides
Trimethoprim
Valproic acid
Vemurafenib*
Drugs causing hoarseness
Inhaled corticosteroids
Antihistamines, decongestants, anticholinergics
Angiotensin-converting-enzyme inhibitors (ACE inhibitors)
Bisphosphonates
Anticoagulants
Antipsychotics
Muscle relaxants
COC
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