There are some important things to consider before taking antibiotics.
Do not take one of the penicillin-based antibiotics if you've had an allergic reaction to them in the past. People who are allergic to one type of penicillin will be allergic to all of them.
Penicillins may need to be used at lower doses and with extra caution if you have:
- severe kidney disease
- liver disease
Pregnancy and breastfeeding
You can take most penicillins during pregnancy and breastfeeding in the usual doses.
Tell your healthcare professional if you're pregnant or breastfeeding, so they can prescribe the most suitable antibiotic for you.
If you previously had an allergic reaction to penicillin, there's a chance that you may also be allergic to cephalosporins.
Cephalosporins may not be suitable if you have kidney disease, but if you need one you will probably be given a lower than usual dose.
If you're pregnant or breastfeeding – or have a rare inherited blood disorder called acute porphyria – check with your doctor, midwife or pharmacist before taking cephalosporins.
Aminoglycosides are normally only used in hospital to treat life-threatening health conditions such as septicaemia, as they can cause kidney damage in people with pre-existing kidney disease.
They're only used during pregnancy if your doctor believes they're essential.
Tetracyclines are not usually recommended unless absolutely necessary in:
- people with kidney disease – except doxycycline, which can be used
- people with liver disease
- people with the autoimmune illness called lupus – which can cause skin problems, joint pain and swelling, and fatigue
- children under the age of 12
- pregnant or breastfeeding women
Do not take macrolides if you have porphyria – a rare inherited blood disorder.
If you're pregnant or breastfeeding, the only type of macrolide you can take is erythromycin (also called by the brand names Erymax, Erythrocin, Erythroped or Erythroped A) unless a different antibiotic is recommended by your doctor.
You can take erythromycin at the usual doses throughout your pregnancy and while you're breastfeeding.
Other macrolides should not be used during pregnancy, unless advised by a specialist.
Fluoroquinolones are not normally suitable for women who are pregnant or breastfeeding.