Hi,
I wrote this article in a local newspaper fortnightly column in Oct 2001 - the information is just as relevant today.
Enjoy.
dr tan
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911 and the ongoing anthrax scare has converted the chronic kia-su among us into terminal kia-si cases. Should we stock up antibiotics or be secretly popping them in the (now-not-so-unlikely) event some white powder lands on our desk?
Antibiotics can stop some infections and save lives, but when inappropriately used can cause more harm than good. They do not work against viruses or fungal infections. For these, you need anti-virals and anti-fungals respectively.
Before doctors prescribe antibiotics, there are some questions they must ask. Does the patient have an infection? What pathogens are likely? Are there epidemiological clues as to whether the cause is bacterial, viral or non infectious? Will it benefit from antibiotic therapy? Which antibiotic (group), what route, dose, and dosing frequency? How urgent is treatment? Will the site of infection be reached? Does anything about the patient (child, pregnant or lactating woman, elderly) limit the choice of agent? Do the benefits of treatment outweigh the potential adverse effects of the antibiotics? Does treatment need review or monitoring? What duration of treatment is needed?
Antibiotics are ‘smart bombs” that specifically target bacterial cells or parts thereof.
(Users must be smart too!)
The basis of anti-microbial treatment is to arrest the growth of the causal pathogen while the body’s immune defense system kills it. In order to avoid unwanted toxic effects, most antibiotics are chosen because they damage certain critical components of the bacterial cell, but not the host or human cell.
Each antibiotic group works in different ways. Penicillins interfere with the cell wall synthesis of new cells or damage the proteins in the existing cell wall making the bacteria susceptible to being “blown up”. Others act like detergents on the cell membrane, causing them to leak or break up. Tetracyclines (eg. doxycycline – the drug currently used in the treatment of those who have potentially been exposed to Anthrax spores) stops the bacteria from producing proteins for its new cell. Quinolones (ciprofloxacillin is in this category) act on the bacterial genes by disrupting the DNA replication, hence disrupting cell multiplication. Because they act at the genetic level, its use is not recommended in children below 18years.
Antibiotics do not work against all infections
Antibiotics only work against bacteria. They do not work at all against infections caused by viruses, fungus or parasites. Each antibiotic group is effective against a range of bacteria – this is called its spectrum of activity. The spectrum may be extended by adding another agent with a different spectrum.
Penicillins as a group are good for many of the bacteria causing skin, throat or chest infections, (and venereal disease like gonorrhoea or syphilis) but are not effective at all against those that cause gut or urine infections. For example, when newborn babies are admitted for suspected infection , they are usually put on a cocktail of a penicillin and an aminoglycoside, the later to cover the gut or urine bacteria that the neonate may have picked up from passing through the mother’s birth canal.
Before starting antibiotics, skin swabs , blood, urine or cerebrospinal fluid have to be sent for cultures to try to identify the responsible organisms. These are inoculated onto specific media plates or broth to incubate. If nothing grows within 24 hours, the laboratory will usually report “no growth”. This helps the doctors to review the need for discontinuation or change of antibiotics which had been empirically started.
If the media plates shows bacteria growth, the bacteria can then be microscopically identified and their sensitivity to different groups of antibiotics tested. This is called “culture and sensitivity” (C&S). When the C&S report say that the bacteria isolated is resistant to the antibiotics being used, the doctors will have to consider changing the antibiotic to one to which it is sensitive.
Antibiotic abuse promotes survival of resistant bacteria strains
Usually antibiotics kill bacteria or stop them from growing. However, some bacteria have become resistant to specific antibiotics so the antibiotics no longer work against them. Resistant bacteria develop faster when antibiotics are used too often or are not used correctly. Buying antibiotics over the counter to treat yourself may be priming your body’s germs to develop resistance, and make future treatment of infections more problematic, costly and potentially life threatening.
Antibiotics whenever prescribed must be taken in the right dose, with the correct timing and for the right reasons.
Do not expect antibiotics to cure every illness. Do not take antibiotics for colds or the flu.
Sore throat, cough or bronchiolitis are usually caused by viruses. A runny nose and yellow or green mucus do not necessarily mean you need an antibiotic. However, if you have a problem with your tonsils, sinuses, lungs or an illness that lasts a long time, bacteria may actually be the cause. Your doctor may use an antibiotic.
On the other hand, there are some conditions where antibiotic use is mandatory. This must be emphasized as some parents are increasingly unhappy about putting their kids on antibiotics. A bacteria called Beta Streptococcus causing sore throats or skin infections in children must be eradicated with antibiotics. In some susceptible children, failure to kill this bacteria early may cause them to produce antibodies which unfortunately attack the heart, joints and kidneys producing rheumatic heart disease, rheumatic fever, and acute glomerulonephritis respectively. Once a child has been diagnosed to have any of these conditions, they will be required to take penicillin daily for the rest of their life to prevent further debilitating damage to their susceptible organs. In this case not taking antibiotic is not an option!
Likewise, people with holes in the heart, abnormal or artificial valves or implants will need to protect themselves by taking antibiotics prophylactically before all surgical and all dental procedures. This is because such procedures invariably seed bacteria into the blood stream. If these “opportunists” are not killed on entry, they may colonize the abnormal structures and cause a serious life threatening infection. Killing bacteria before they get a chance to settle down and multiply is called “chemo-prophylaxis”.
Smart use of Antibiotics
When a doctor tells you to take an antibiotic “three times a day” (tds) he often forgets to tell you that his day is 24 hours while yours is 12! This is a world of difference. If you took antibiotics at 7am, 12am & 7pm (your tds), your overnight antibiotic blood level will fall below the effective levels necessary to inhibit bacterial growth.
Some of the newer (more expensive) antibiotics can be taken once a day. Others need twice to four times a day dosing. Those that are rapidly cleared by the kidneys or liver will need more frequent dosing. If one dose is omitted for whatever reason, the next dose should be taken when you remember, without increasing the dose. It is quite important to take the antibiotics in the frequency as prescribed. Changing arbitrarily a tds dosing (8 hourly) to o.d (once a day) is not good, as the drug level in the blood may not reach the “killing concentration” needed.
If you or your child really hate taking medicines and find it easier to take the least possible doses, please inform your doctor. There are alternatives (unfortunately they tend to be more expensive!).
But do give drugs and antibiotics (and doctors) some time, before you decide they do not work and run to the next doctor/pharmacy/chinese sinseh. Oral antibiotics may need a good 24 hours before you feel its full effect, because the drug level in the blood takes time to build up and because the bacteria population takes time to fall. Injection antibiotics work faster , especially if given intravenous in the hospital setting, but the risks associated with the injection has to be worth the speed.
Changing doctors and medications every six to eight hours is not smart, not just for your pocket.
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