Prescribing in special cases Flashcards
ACE-I affect K levels how?
Hyperkaleamia
Diuretics affect K levels how?
Hypokalaemia. (Except for K sparing, diuretics. For these combine with loop diuretics).
Can you co-prescribe ACE-I and diuretics?
Yes, they can cancel each other out, which is great. But spironolactone and amiloride are to be avoided, since they are potassium sparing. MONITOR MONITOR
Loop diuretics?
Furosemide
Bumetanide
K sparing diuretics?
spironolactone and amiloride
Thiazides?
Chlortalidone and indapamide
Renal failure: how do you prescribe?
Check BNF and adjust dosage for drug
or
Use alternative approach
Why might using an alternative approach for renal impairment be helpful?
Gentamycin: increase the dosage interval
tolbutamide as a choice sulphonylurea: is short-acting, doesn’t accumulate as much
Hypertension: amlodopine, non-renally excreted
Metformin and Renal impairment
Absolutely no if eGFR too low, metabolic disturbances, won’t clear.
Thiazide diuretics and Renal impairment?
won’t work, depend on renal function to function itself
Key issue with prescribing in pregnancy?
Everything, bar heparins, crosses placenta
Assume that all females of child-bearing age are pregnant unless you know otherwise (could become pregnant whilst taking this medication). Window in first few months often the issue
Anti-epileptics and pregnancy?
Harm in first trimester -Phenytoin craniofacial abnormalities hypoplasia of distal phalanges growth deficiency mental deficiency -Valproate associated with neural tube defects (spinal cord not closing) -Carbamazepine similar to phenytoin but decreased risk
Continuation of treatment is preferable - counselling
Or planned discontinuation
Carbamazepine was preferred
5mg folic acid given to reduce chances of neural tube defect
Lamotrigine used first line in generalised tonic-clonic seizures to avoid teratogenic / interacting drugs.
Hormones of pregnancy reduce its levels
anti-hypertensives and pregnancy?
ACE-I are not allowed, use beta-blockers instead or calcium-channel blockers, or methyl-dopa
Anti-coagulants and pregnancy?
Warfarin: teratogenics, particularly in semester 1 & 3
Use a LMWH instead!!
Do you use LFT as a guidance for hepatic impairment?
No, they are far less quantitative. Not like with GFR
