Practice Flashcards
What drugs increase enzyme activity and reduce drug concentration?
- Phenytoin
- Carbamazepine
- Barbituates
- Rifampicin
- Alcohol (chronic excess)
- Sulphonylureas
What drugs reduce enzyme activity and increase drug concentration?
- Allopurinol
- Omeprazole
- Disulfiram
- Erythromycin
- Valproate
- Isoniazide
- Ciprofloxacin
- Ethanol (acute intoxication)
- Suphonamides
What medications need to be stopped before surgery?
I LACK OP
- Insulin
- Lithium
- Anticoagulants/antiplatelets
- COCP/HRT
- K-sparing diuretics
- Oral hypoglycaemics
- Perindopril and other ACEi
How far in advance do medications need to be stopped before surgery?
- COCP/HRT - 4 weeks
- Lithium - day before
- K-sparing and ACEi - day of
- Anticoagulants/antiplatelets - variable (occasionally continued)
- Oral hypoglycaemic drugs - variable
- When NBM stop metformin otherwise lactic acidosis, can use a sliding scale.
What drug can increase INR?
Erythromycin
What are the side effects of steroids?
STEROIDS
- Stomach ulcers
- Thin skin
- oEdema
- Right and left HF
- Osteoporosis
- Infection e.g. candida
- Diabetes (hypoglycaemia, sometimes progresses to diabetes)
- cushing’s Syndrome
What are the safety considerations of NSAIDs?
NSAIDs
- No urine i.e. renal failure
- Systolic dysfunction i.e. HF
- Asthma
- Indigestion (any cause)
- Dyscrasia (clotting abnormality)
What are the side effects of antihypertensives?
- Hypotension i.e. postural
- Bradycardia - beta blockers, some CCBs
- Electrolyte disturbances with ACEi and diuretics
- ACEi - dry cough
- Beta blockers - wheeze in asthma, worsening of acute HF (help in chronic HF)
- CCBs - peripheral oedema and flushing
- Diuretics - renal failure
- Thiazide diuretics e.g. bendroflumethzide - gout
- K-sparing diuretics e.g. spironolactone - gynaecomastia
What VTE prophylaxis is needed?
- The majority will receive LMWH e.g. dalteparin 5000 units OD SC and compression stockings.
- Patients with PAD (absent foot pulses) - no compression stockings
Who should avoid metoclopramide?
- Young women
- Parkinson’s
Due to dyskinesia i.e. unwanted movements, especially acute dystonia
What anti-emetics are used?
- Cyclizine 50mg 8hrly IM/IV/oral - can cause fluid retention, can prescribe PRN
- Metoclopramide 10mg 8hrly IM/IV if HF
- Ondansetron 4mg or 8mg 8hrly IV/oral
What is used in neuropathic pain?
Amitriptyline 10mg PO ON or pregabalin 75mg PO 12hrly
What is used for pain in diabetic neuropathy?
Duloxetine 60mg PO OD
What are the side effects of oxybutinin?
- Antimuscarinic drug used for urinary frequency and urgency
- Confusion, particularly in elderly
- Pupil dilation with loss of accommodation
- Dry mouth
- Tachycardia
What could cause confusion in the elderly?
- Acute intracranial event
- Infection
- Electrolyte disturbance
- Urinary retention +/or constipation
- Opioids e.g. tramadol
- Cyclizine
- Benzodiazepines
What are the contraindications for methotrexate?
- NSAIDs use with caution due to nephrotoxicity
- Infection
- Pregnancy
- Trimethoprim - increases bone marrow toxicity
What is the maximum dose of paracetamol per day?
4g/day
What route is insulin given?
Subcutaneous, except for sliding scale use IV short-acting insulin e.g. actrapid or novorapid
What are the side effects of antipsychotics?
- Agranulocytosis - neutropenia
- Requires immediate cessation of drug and referral to haematologist
What medications cause agranulocytosis?
- Antipsychotics
- Carbimazole
- Carbamazepine
What are the causes of respiratory alkalosis?
Rapid breathing - disease or anxiety
What are the causes of respiratory acidosis?
Same causes as T2RF ‘blue bloaters’
What are the causes of metabolic alkalosis?
- Vomiting
- Diuretics
- Conn’s syndrome
What are the causes of metabolic acidosis?
- Lactic acidosis
- DKA
- Renal failure
- Ethanol/methanol/ethylene glycol intoxication
What are general rules of abx use?
- Flucloxacillin 1st for skin infections
- Metronidazole typically used for GI infections due to good effects on anaerobes that colonise the gut
- Clindamycin usually for bone infections
What are the side effects of cyclizine?
- Acute closure glaucoma
- Dry mouth
- Dizzy (anti-muscarinic)
What are the risks of tamoxifen?
- Increase risk of endometrial carcinoma
- Increase efficacy of warfarin - increase INR
- Increase risk of VTE
What are the side effects of citalopram?
- Photosensitive - precautions should be taken in sunlight
- Dry mouth
- Serotonin syndrome: agitation, increased temp, hallucinations
- Can still have suicidal thoughts, seek help immediately. Can take up to 6 weeks to see improvement.
What does phenytoin commonly interact with?
COCP - reduces efficacy. IUD are recommended instead if the patient is on OCP.
