How Long Does It Take for Antibiotics to Work?

If you have ever sat up at night with a sick child who got well after an injection of antibiotics, you probably appreciate the power of modern treatment of infectious disease. In the 1940's, when antibiotics first became generally available, they were considered to be miracle drugs. Before the introduction of antibiotics, something as simple as stepping on a nail or cutting your hand on broken glass could quickly result in death. After the introduction of antibiotics, infections that had killed millions of people in the prime of life became manageable, sometimes with just few injections of a few tablets of the right antibiotic.

Modern antibiotics are not entirely beneficial, or free of side effects.

By the 1980's, however, antibiotics had begun to be regarded as something of a mixed blessing. Some people were allergic to antibiotics. There had been thousands of deaths (out hundreds of millions of treatments) due to allergic reactions to antibiotics. Moreover, bacteria began to be able to "outsmart" antibiotics. By chance, some bacteria would have genetics that enabled them to resist the effects of medications. They could pass these genes to other bacteria without having to reproduce themselves, making them also resistant to the drug. The more often an antibiotic is used, the more bacteria that are resistant to it, making many medications less and less useful as time goes by. Because many antibiotics are used not just to treat diseases in people but also to help livestock gain weight, antibiotic resistance is becoming a worldwide problem.[1]

Antibiotic resistance is one of the biggest threats to global health, food security, and development today. It can affect anyone, of any age, in any country: a growing number of infections – such as pneumonia, tuberculosis, and gonorrhoea – are becoming harder to treat as the antibiotics used to treat them become less effective.

The answer to the question "How long does it take antibiotics to work?" is always longer than it takes to start feeling better.

It may take 24 hours or less to start feeling better when the doctor has prescribed the right antibiotic for your illness. It may take longer if the doctor has made an ill-advised choice. Most antibiotics get demonstrable results in less than 48 hours. However, the antibiotic still has more work to do even after you start feeling better.

READ New Bugs, Old Drugs: How Old Antibiotics Can Help Fight New Infections

Symptoms begin to subside when a majority of bacteria have been killed. However, a few stronger bacteria may hang on even after most others have died. It is important to kill those bacteria, too, because stopping antibiotic treatment too soon will allow them to multiply unchecked. An infection may "rebound" a few days after symptoms subside, and because the new infection is caused by stronger, meaner, nastier bacteria, it will take longer to get back under control. If this process is repeated often enough, there will eventually be a strain of bacteria that cannot be controlled by antibiotics at all. That is precisely what has been happening with countless antibiotics used to treat dozens of infections all over the world.[1]

What Your Doctor May Not Tell You About Antibiotics

There is a lot your doctor may not have time to tell you about antibiotics. Continuing with the list, here are more important suggestions.

All antibiotics aren't priced the same.

Some antibiotics are much more expensive than others. Z-Pack (Zithromax, azithromycin) is popular, easy to use, and only requires five doses instead of the usual ten, but it also can cost five times as much as other antibiotics that are more effective but require taking ten doses. If you are not allergic to penicillin and your doctor offers any form of azithromycine as your first treatment, ask about less expensive drugs.

There are no antibiotics for flu and colds.

Antibiotics never treat viral infections. They are almost always used to treat bacterial infections. Sometimes the only way your doctor can tell whether an infection is viral or bacteria is to take a swab and to run a culture. This process can take one or two days. If your doctor gives you an antibiotic for a viral infection, it won't work, but it will kill beneficial bacteria that keep disease bacteria in check.

Different antibiotics are used to treat different kinds of infections.

The penicillins, Amoxicillin and Penicillin-G, were once employed as the first-line antibiotic for strep throat, but because they do not work as well as they used to for strep, they are now more commonly used for uncomplicated sinus and ear infections, especially in children. These medications are popular because of their bubble gum flavor. Children usually don't mind having to take them twice a day.

Sulfa drugs, such as Bactrim and Septra, are used to treat urinary tract infections. Many people are allergic to them, and they increase the sensitivity of the skin to sunburn.

Beta-lactamase inhibitors, such as Amoxicillin-Clavulanic Acid and Augmentin, are effective against recurring cases of strep throat and ear infections, but most children don't like to take them, because of their chalky, milk of magnesia-like consistency. They have to be given twice a day for ten days.

Cephalosporins, such as Cedax and Omnicef, are used when children (and sometimes adults) just can't stand the taste of Augmentin. They don't work as well in fighting infections but they are easier to swallow.

Azithromycin, sold as Zithromax and Z-Pack, is effective against a pneumonia and whooping cough. In most cases, it should not be the first antibiotic the doctor tries for treating the infection.

READ Is Your Doctor Prescribing Antibiotics You Don't Need?

You can make it easier for your child to take antibiotics.

Sometimes you have to give your child an antibiotic that tastes bad. It usually helps to disguise it with food, such as applesauce or pudding. It is usually not a good idea to mix an antibiotic with infant formula, because there is no guarantee the baby will drink the whole bottle all at once. Most children will be glad to know, however, that the absorption of many antibiotics is better when they are taken with a fatty food, such as ice cream.

Some of the worst infections can be avoided by washing your hands frequently.

Some especially nasty bacterial infections, such as the resistant form of staph bacteria known as MRSA, are harder to catch if you wash your hands frequently. For adults, this can mean washing your hands before you use the toilet as well as after. In taking care of children, the more hand washing, the better. Ten times a day is not too much.