A B C D E F G H I J K L M N O P R S T U V W

ANTIBIOTICS

What are the types of Antibiotics ?

Penicillins were the first antibiotics to be used. Drugs of this type are still used widely: they almost all end in "...cillin". Many other types of antibiotics are now used. They tend to end in "...cycline", "..mycin", "...oxacin" or begin with "ceph.." or "cef..". These terms help to identify the particular chemical group of an antibiotic.

What are Antibiotics for ?

They are used for infections which are known, or thought, to be due to bacteria. Antibiotics are very rarely active against viruses. Furthermore, it is important to realize that the more common infections due to viruses mostly do little permanent damage and get better by themselves: this is why antibiotics are not prescribed for every infection. They are sometimes also used to prevent you from getting an infection.

How do Antibiotics work ?

Antibiotics either kill the bacteria or just stop them from multiplying. This then makes it possible for your own body's defence (or immune) system to play its part in getting rid of them. Some antibiotics are effective against a large number of different types of germs. These are called "broad-range" antibiotics. Others only destroy one particular type. Your doctor will prescribe an antibiotic which is effective against the type of germ that is known, or thought, to be causing your infection. A sample of the relevant tissue fluid (phlegm, blood, urine or a discharge) allows the laboratory to give your doctor a guide as to whether he or she has chosen correctly.

How should Antibiotics be used ?

Tablets or capsules should be taken with a glass of water, between one and four times a day. It is important to take them the correct number of times a day: this should be written clearly on the label. If you are not sure, ask your doctor or pharmacist. You must take the full course which your doctor has prescribed for you even if you feel better. Some antibiotics are better taken after food and some work better if taken on an empty stomach. Check the label, or ask your pharmacist if you are not sure.

During Treatment with Antibiotics

You should start feeling better within a couple of days, although some antibiotics take several days to work. If you feel no improvement in your infection, contact your doctor: do not just stop the antibiotics. Most antibiotics are very safe. However, a mild rash, indigestion and sick feelings or diarrhoea can occur with any antibiotic. The most common serious reaction is a severe allergic reaction which might cause bad itching, fever, and sometimes swelling of the face and throat, wheezing, or pain or swelling of the joints. If this happens, stop your antibiotic immediately and contact your doctor.

Some antibiotics (especially the "...mycins") can cause nausea, vomiting or abdominal pain. The risk of these side-effects is less if the antibiotic is taken with food. Most antibiotics, especially the broad range ones, can cause diarrhoea. If this happens, tell your doctor. Taking antibiotics, especially for a long time, can change the balance of innocent germs which normally exist harmlessly within your body. Any imbalance allows a yeast organism called candida to flourish. Thrush is the name given to this complication which can affect the mouth, vagina or bowel. Irritation, pain and a discharge in these areas occurs. A more serious upset of normal germs can occur in the gut causing violent diarrhoea which may contain blood. This is only likely to happen with the antibiotic, clindamycin. If it does, stop taking your antibiotic and contact your doctor immediately. Other symptoms can occur: it is safest to let your doctor know if anything unusual occurs.

Drug Interference

Blood thinners (anticoagulants) are made more active by many antibiotics. This increases the risk of bleeding. A lower dose of your blood thinner may be advised by the doctor. Some antihistamines can provoke an irregular heartbeat with some of the "..mycins". Do not take these together. Oral contraceptives are made less effective by "broad range" antibiotics like amoxycillin and tetracycline. The risk is small, but you would be wise to use an additional form of contraception while on antibiotics, and for 7 days afterwards. Digoxin is made more active by erythromycin (and possibly other "..mycins". Watch out for loss of appetite, nausea and vomiting. Your doctor may reduce your digoxin dose. Indigestion remedies (antacids) and iron medication may reduce the amount of some antibiotics your body can absorb. This will reduce the effectiveness of some antibiotics, including tetracyclines or « ..oxacin » drugs. Take your indigestion remedy or iron medication at a different time of the day from your antibiotics to avoid this problem. Alcohol taken at the same time as metronidazole can cause nausea, vomiting, flushing and stomach pain. With other antibiotics it is better to cut back alcohol too. Antibiotics can sometimes reduce the action of anti-epileptic drugs. Your doctor may therefore change the dose of your anti-epileptic medication. This is not a full list. If in doubt, check with your doctor or pharmacist about any other treatment you are taking.

What if Antibiotics are not taken ?

If you stop taking your antibiotics before finishing the full course your infection may return. It may even become more difficult to treat.

General advice on Antibiotics

Glandular fever will cause you to have a rash with ampicillin. If you are pregnant, both ampicillin and amoxycillin should be avoided for your baby's sake, These and other antibiotics are generally safe if you are breast-feeding, but discuss this with your doctor.