14. Pharmacology of absorption, metabolism and excretion Flashcards
Administering Tetracycline
Leave a 2-hour gap between tetracyclines and magnesium hydroxide
Effect of magnesium hydroxide on tetracycline?
Magnesium hydroxide increases pH
The metal ions form chelates with tetracyclines which are not absorbed at high pH
Levels of tetracyclines greatly reduced
Administering Risedronate
Leave a gap of at least 2 hours between giving calcium and risedronate
must also be given on an empty stomach
Fluconazole
Enzyme inhibitor
Itraconazole
Enzyme inhibitor
Domperidone effect on gut motility
Increases
Alcohol
Enzyme inducer
Why is Diazepam given by rectal route?
for status epilepticus
IV access = difficult
Oral = unavailable
Rifampicin
Enzyme inducer
Domperidone effect on gastric emptying
Increases
Chloramphenicol
Enzyme inhibitor
Why is Mesalazine given by rectal route?
severe ulcerative colitis
Local anti-inflammatory effect
less systemic side effects
carbamazepine
enzyme inducer
barbiturates
enzyme inducer
Verapamil
Enzyme inhibitor
Effect of calcium carbonate on risedronate?
Chelates calcium ions
Resultant chelate insoluble
Domperidone effect on motility
Increases
Morphine effect on motility
Decreases
Domperidone effect on drug absorption
Increases
Morphine effect on gut tone
Increases
phenytoin
enyme inducer
Cimetidine
Enzyme inhibitor
Why is there a problem giving rifampicin with Microgynon 30?
Reduction in pill efficacy
Alternative method of contraception for up to 4 weeks after
Ketoconazole
Enzyme inhibitor
Increased splanchnic blood flow
Increased absorption of drugs
Domperidone effect on duodenal peristalsis + contractions in the stomach
Increases
Which phase metabolises Warfarin
Phase 1
Decreased splanchnic blood flow
decreased absorption of drugs
Which phase metabolises Paracetamol
Phase 2
Isoniazid
Enzyme inhibitor
Which phase metabolises Alcohol
Phase 1
Erythromycin
Enzyme inhibitor
Which phase metabolises Diazepam
Phase 1
Morphine effect on drug absorption
Decreases
Which phase metabolises Caffeine
Phase 1
Ciprofloxacin
Enzyme inhibitor
Which phase metabolises Isoniazid
Phase 2
Why is Decussate given by rectal route?
for constipation
Local effect on colon
higher dose possible with less side effects
Why is Metronidazolegiven by rectal route?
antibiotic
When oral and IV routes not available.
Diltiazem
Enzyme inhibitor
Morphine effect on gastric emptying
Decreases
Domperidone effect on tone
Increases tone
of the lower oesophageal sphincter
