tetracyclines Flashcards
cautions for all tetracyclines (2)
myasthenia gravis - muscle weakness may be increased
- SLE may be exacerbated
common side effects
- angiodema
- hypersensivitiy
- diarrhhoea
- headache
- nausea
- pericarditis
- photosensitivity reaction
- skin reactions
- SLE exacerbated
- vomiting
- headache and visual disturbances (may indicate benign intracranial hypertension - discontinue if raised IC pressure develops!)
what is Henoch-Schonlein purpora?
inflammation of small blood vessels which leak into skin, joints, intestines and kidneys
appears as purpuric rash
Henoch Schonlein purpura
common side effect of tetracyclines
headache and visual disturbances as a side effect of tetracyclines can indicate…
benign intracranial hypertension
discontinue if raised intracranial pressure
can you use in pregnancy and why
- no
- 1st trimester: animal studies show effects of skeletal development
- 2nd trimester: can cause discolouration of child teeth
- maternal hepatotoxicity with large parenteral doses
can you use in BF and why
Do not give, although absorption and therefore discoloration of teeth in infant is probably usually prevented by chelation with calcium in milk
DLM
do like milk - doxy, Lyme, minocycline
DOT
don’t like milk - demeclo, oxytetra, tetracycline
photosensitivity reactions are more likely with this abx than other tetracyclines
demeclocycline
tetracyclines are …. toxic
hepatotoxic
which abx is used for treatment of hyponatraemia resulting from inappropriate secretion of ADH if fluid restriction alone does not restore sodium conc or is not tolerable?
demeclocycline
doxycycline is normally contraindicated in pregnancy because of risk of skeletal development impaired and staining of teeth in baby. however, if travel to malarias areas is unavoidable and other regimens are unsuitable, it can be used for malaria prophylaxis if the entire course can be completed before…..
15 weeks gestation
labelling requirements for doxycycline (in addition to standard abx ones)
- do not take indigestion remedies or iron or zinc 2h before or after …
- protect skin from sunlight ….
- take with full glass of water….
which abx has an additional warning label of ‘take with full glass of water’?
doxycycline
which abx is associated with a greater risk of lupus-erythematous like syndrome compared to other tetracyclines?
minocycline
which abx sometimes causes irreversible pigmentation?
minocycline
tetracyclines are contraindicated in this age … because…
- <12
- deposition in growing bone and teeth, by binding to calcium, causes staining and occasionally dental hypoplasia
dairy products decrease the exposure to these 3 abx
demeclo, oxytetra, tetracycline
avoid 1 hour before or 2 hours
DOT
interactions - retinoids
increased risk of being intracranial hypertension. avoid
interactions - warfarin, acenocoumarol, pheninidoine
increases AC effect - monitor INR
interactions - which drugs increase risk of hepatotoxicity
- azoles
- vitamin A
- valproate
- thalidomide
- testosterone
- statins
- paracetamol
- MTX
- mercaptopurine
- heparin
- isoniazid
- fluorouracil
- amiodarone
does MTX interact?
increased risk of hepatotoxicity
does lithium interact?
abx predicted to INCREASE risk of lithium toxicity
avoid or adjust dose
can you take iron and tetracyclines at the same time
Decreases absorption of oral abx
Take abx 2-3 hours after iron
can you take calcium at the same time as tetracyclines
oral calcium predicted to decrease absorption of abx.
separate by 2-3 hours
can you take oral bismuth and antacids at the same time as tetracyclines
separate by 2-3 hours
greatly decreases efficacy of oral abx
can you take zinc at the same time as tetracyclines
decreases absorption of abx separate administration by 2-3 hours
dose of doxycycline in CAP, acute cough, acute sinusitis
200mg stat, then 100mg once daily. total 5 days. total you would prescribe = 6 tablets
dose of doxycycline for HAP
200mg stat, then 100mg once daily. total 5 days, then review
dose of doxycycline for acute exacerbation of bronchiectasis
200mg stat, then 100mg once daily for 7-14 days total
dose of doxycycline for acute exacerbation of COPD
200mg stat then 100mg OD for 5 days total
increased if necessary to 200mg OD (severe infections)
dose of doxycycline for PID
100mg BD for 14 days
oxytetracycline labels (in addition to space doses evenly, take course until finished) - 2
DOT - do not take milk, indigestion remedies, or meds containing iron or zinc 2 hr before or after
take on empty stomach - an hour before food or 2 h after food
does doxycycline need to be taken with food
doesnt matter
this tetracycline has a broader spectrum than the others
minocycline
labelling requirements for oxytetracycline (3)
- do not take milk, indigestion remedies, iron, zinc 2h before or after
- space dose evenly …
- empty stomach (1h before, 2 h after food)
tetracycline labelling requirmenets (3)
- no milk, indigestion remedies, iron, zinc 2h before or after
- space doses evenly
- empty stomach
minocyclcine labelling requirements
- no indigestion remedies, iron or zinc 2h before or after
- space doses evenly
demecleocycline labelling requirments (4)
- no milk, indigestion, iron, zinc 2 h before or after
- space doses evenly
- protect skin from sun
- empty stomach
lymecycline labelling requirements (2)
space doses evenly
do not take indigestion, iron, zinc 2h before or after
Summarise which tetracyclines need to be taken on an empty stomach
DOT - demecleo, oxytet, tetra
Which 2 tetracyclines have the additional label ‘protect skin even on a bright by cloudy day’
doxy & demecleo
which 3 tetracyclines need to be taken on an empty stomach
demecleo
tetra
oxytetra
DOT is applicable for 3 things
demecleo, oxytetra, tetracycline
no milk
empty stomach
avoid dairy 1h before or 2h after
which one causes tongue discolouration
minocycline
