Hesperian Health Guides
First Aid: Medicines
Contents
- 1 Antibiotics
- 1.1 The penicillins
- 1.2 Ampicillin and Amoxicillin
- 1.3 Amoxicillin with clavulanic acid(Amoxicillin-clavulanate potassium)
- 1.4 Penicillin by mouth, penicillin V, penicillin VK
- 1.5 Injectable penicillin, penicillin G
- 1.6 Cloxacillin
- 1.7 Dicloxacillin
- 1.8 Other antibiotics
- 1.9 Erythromycin
- 1.10 Tetracycline and Doxycycline
- 1.11 Cotrimoxazole, sulfamethoxazole with trimethoprim, TMP-SMX
- 1.12 Clindamycin
- 1.13 Metronidazole
- 1.14 Ciprofloxacin
- 1.15 Ceftriaxone
- 1.16 Cephalexin
- 1.17 Gentamicin
Antibiotics
Antibiotics are medicines that fight infection from bacteria. They do not help against infections from a virus such as chicken pox, rubella, flu, or the common cold. Not all antibiotics will fight all infections from bacteria.
Antibiotics that share the same chemical make-up are said to be from the same family. It is important to know about the families of antibiotics for two reasons:
- Antibiotics from the same family can often treat the same problems. This means you can use a different medicine from the same family.
- If you are allergic to an antibiotic of one family, you will also be allergic to the other members of the same family of antibiotics. This means you will have to take not just a different medicine, but a medicine from a different family instead.
Antibiotics must be given for their full course. Stopping before you have finished all the days of treatment, even if you feel better, can make the infection return in a form that is even harder to stop.
The penicillins
Medicines in the penicillin family are some of the most useful antibiotics because they fight many infections.
Penicillin is measured in milligrams (mg) or units (U). For penicillin G, 250 mg = 400,000 U.
For most people, penicillin is one of the safest medicines. Using more than the recommended amount wastes money but is not likely to harm the person.
Resistance to penicillin
Certain infections have become resistant to penicillin. This means that in the past penicillin would have been able to cure someone with these infections, but now penicillin does not work. If the infection does not respond to ordinary penicillin, try a different form of penicillin or an antibiotic from another family. For example, pneumonia is sometimes resistant to penicillin. Try cotrimoxazole or erythromycin.
Some people are allergic to penicillin. Mild allergic reactions cause a rash. Often this comes several hours or days after taking penicillin and may last for days. Stop taking the penicillin immediately. Antihistamines help calm the itching. Stomach upset and diarrhea from taking penicillin are not signs of an allergic reaction and, while uncomfortable, are not a reason to stop taking it.
Rarely, penicillin can cause a severe allergy called allergic shock. Within a few minutes or hours after taking penicillin, the person becomes flushed, gets a swollen throat and lips, has trouble breathing, feels faint, and goes into a state of shock. This is very dangerous. Epinephrine (adrenalin) must be injected at once. Always have epinephrine ready when you inject penicillin.
Someone who has once had an allergic reaction to penicillin should not be given any kind of penicillin—ampicillin, amoxicillin, or others—ever again, either by mouth or by injection. This is because the next time the allergic reaction could be worse and might even kill him. People allergic to penicillin can use erythromycin or other antibiotics instead.
Injections
Penicillin usually works well when given by mouth. Injected forms of penicillin can be dangerous. They are more likely to cause severe allergic reactions and other problems, and should be used with caution. Use injectable penicillin only for severe or dangerous infections.
Ampicillin and Amoxicillin
Ampicillin and amoxicillin are broad-spectrum penicillins, which means they kill many kinds of bacteria. The two are often interchangeable. When you see a recommendation for ampicillin in this book, you will often be able to use amoxicillin in its place, in the correct dose.
Ampicillin and amoxicillin are very safe and are especially useful for babies and small children.
Both these medicines, but especially ampicillin, tend to cause nausea and diarrhea. Avoid giving them to people who already have diarrhea if you can give another antibiotic instead.
The other common side effect is rash. But raised, itchy bumps that come and go in a few hours are probably a sign of penicillin allergy. Stop giving the medicine right away and do not give the person a penicillin medicine again. Future allergic reactions may be more severe and even life-threatening. For some problems, erythromycin can be used instead. A flat rash that looks like measles, and usually appears a week after starting the medicine and takes days to go away, is not necessarily an allergy. But it is impossible to know for sure if the rash is from allergy or not, so it is usually better to stop taking the medicine.
Ampicillin and amoxicillin work well when taken by mouth. Ampicillin can also be given by injection for severe illnesses.
As with other antibiotics, always give these medicines for at least the shorter number of days shown here. If the person still has signs of infection, have her continue taking the same amount every day until all signs of infection have been gone for at least 24 hours. If the person has taken the medicine for the maximum number of days and is still sick, stop giving the antibiotic and get medical help. For people with HIV, always give the medicine for the maximum number of days listed.
Likewise, the amount of antibiotic to take depends on the age or weight of the person and the severity of the infection. In general, give the smaller amount of the range for a thinner person or for a less severe infection, and the larger amount for a heavier person or a more severe infection.
AMOXICILLIN (ORAL)dose by age:
Under 3 months: give 125 mg, 2 times a day for 7 to 10 days.
3 months to 3 years: give 250 mg, 2 times a day for 7 to 10 days.
4 to 7 years: give 375 mg, 2 times a day for 7 to 10 days.
8 to 12 years: give 500 mg, 2 times a day for 7 to 10 days.
Over 12 years: give 500 to 875 mg, 2 times a day for 7 to 10 days.
Under 1 year: give 100 mg, 4 times a day for 7 days.
1 to 3 years: give 125 mg, 4 times a day for 7 days.
4 to 7 years: give 250 mg, 4 times a day for 7 days.
8 to 12 years: give 375 mg, 4 times a day for 7 days.
Over 12 years: give 500 mg, 4 times a day for 7 days.
Ampicillin should be injected only for severe illnesses, or when someone is vomiting or cannot swallow.
dose by age:
Under 1 year: inject 100 mg, 4 times a day for 7 days.
1 to 5 years: inject 300 mg, 4 times a day for 7 days.
6 to 12 years: inject 625 mg, 4 times a day for 7 days.
Over 12 years: inject 875 mg, 4 times a day for 7 days.
Amoxicillin with clavulanic acid
(Amoxicillin-clavulanate potassium)
Amoxicillin with clavulanic acid comes in different strengths of each of the 2 medicines it contains, for example, 500/125 (a 4 to 1 strength because the tablets have 500 mg amoxicillin and 125 mg clavulanic acid) or 875/125 (a 7 to 1 strength). For children, it is best to use the 4 to 1 ratio such as the 500/125 tablet or the liquid medicine where 5 ml contains 125/31.25 or 250/62.5. Often, the dose of amoxicillin with clavulanic acid mentions only the amount of amoxicillin (as we do here).
Give by mouth with food or milk.
For animal bites To prevent infection and using a 4 to 1 strength such as the 500/125 tablet or a syrup made for children, give 20 mg per kg each day for 3 to 5 days, divided into 3 doses. If you cannot weigh the person, dose by age:
1 to 5 years: give 125 mg, 3 times a day for 3 to 5 days.
6 to 12 years: give 250 mg, 3 times a day for 3 to 5 days.
Over 12 years: 250 mg, 3 times a day OR use the 875/125 tablet, 2 times a day for 3 to 5 days.
If the bite is already infected, use the same dose for up to 14 days.
Penicillin by mouth, penicillin V, penicillin VK
Penicillin by mouth (rather than by injection) can be used for mild and moderate infections.
Even if you started with injected penicillin for a severe infection, you can usually switch to penicillin by mouth once the person starts to improve. If improvement does not begin within 2 or 3 days, consider switching to another antibiotic and get medical advice.
To help the body make better use of the medicine, take penicillin on an empty stomach, at least 1 hour before or 2 hours after meals.
dose by age:
Under 1 year: give 62 mg, 4 times a day for 10 days.
1 to 5 years: give 125 mg, 4 times a day for 10 days.
6 to 12 years: give 125 to 250 mg, 4 times a day for 10 days.
Over 12 years: give 250 to 500 mg, 4 times a day for 10 days.
For more serious infections, double the doses above.
For a wound likely to be infected with tetanus, along with medicines to prevent tetanus, antibiotics are sometimes given. For example, give penicillin G for 2 days, switch to penicillin V in the dose above for 5 to 8 more days.
For animal bites, give the dose above for 3 to 5 days. Also give metronidazole OR clindamycin.
Injectable penicillin, penicillin G
Injectable penicillin is used for certain severe infections, including infections from wounds.
Injectable penicillin comes in different forms. The main difference is how long the medicine lasts in the body and how quickly it works: short-acting, intermediate-acting, or long-acting.
PROCAINE PENICILLIN, PROCAINE BENZYLPENICILLIN (intermediate-acting)
Inject only in the muscle (IM), not in the vein (IV).
2 months to 3 years: inject 150,000 units, 1 time a day for 10 to 15 days.
4 to 7 years: inject 300,000 units, 1 time a day for 10 to 15 days.
8 to 12 years: inject 600,000 units, 1 time a day for 10 to 15 days.
Over 12 years: inject 600,000 to 4,800,000 units, 1 time a day for 10 to 15 days.
Do not give to babies under 2 months unless no other penicillin or ampicillin is available. If this is your only choice, inject 50,000 units, 1 time a day for 10 to 15 days.
For very severe infections in any age, double the above dose.
For a wound likely to be infected with tetanus, along with medicines to prevent tetanus, antibiotics are sometimes given. For example, give the above dose for 7 to 10 days. OR, give the above dose for 2 days, then switch to penicillin by mouth (penicillin V).
Cloxacillin
Cloxacillin is a form of penicillin, and can sometimes be used for infections that have become resistant to penicillin, such as sores on the skin with pus, and bone infections. If you do not have cloxacillin, dicloxacillin can be used instead.
Nausea, vomiting, diarrhea, fever, and joint pain.
Do not give if the person is allergic to penicillin.
For most infections
Under 2 years: give 75 mg, 4 times a day.
2 to 10 years: give 125 mg, 4 times a day.
Over 10 years: give 250 to 500 mg, 4 times a day.
Double these amounts for severe infections.
For knife or gunshot wound, give the dose above for 10 to 14 days. If the wound is dirty or in the abdomen, also give metronidazole.
For a bone that has broken through the skin (open fracture), give the dose above for 5 to 7 days. If the wound is very dirty, also give metronidazole.
Dicloxacillin
Dicloxacillin is a form of penicillin, and can sometimes be used for infections that have become resistant to penicillin. If you do not have dicloxacillin, cloxacillin can be used instead.
Nausea, stomach pain, loss of appetite.
- Do not give if the person is allergic to penicillin. Do not give to newborns.
- Stop taking if you begin to have dark urine, gray colored stools or jaundice (yellow skin and eyes).
Give with a full glass of water. Give 1 hour before eating, or 2 hours after eating.
Under 1 year: give 20 mg by mouth, 4 times a day.
1 to 5 years: give 30 mg by mouth, 4 times a day.
6 to 12 years: give 80 mg by mouth, 4 times a day.
Over 12 years: give 125 to 250 mg by mouth, 4 times a day.
For an infected wound, give the dose above for 5 to 7 days. If the wound is very dirty, also give metronidazole.
For a burn that is infected, give the dose above for 5 to 7 days. If it is a deep burn, or the person has a fever, give the dose above for 10 to 14 days.
Other antibiotics
Erythromycin
Erythromycin works against many of the same infections as penicillin and can be used by those who are allergic to penicillins. For many infections, it can also be used in place of tetracycline. It can also be used for diphtheria and pertussis (whooping cough).
Erythromycin often causes nausea and diarrhea, especially in children. Do not use for more than 2 weeks as it may cause jaundice.
dose by age:
Newborns up to 1 month old: give 62 mg, 3 times a day for 7 to 10 days.
1 month to 2 years: give 125 mg, 3 or 4 times a day for 7 to 10 days.
2 to 8 years: give 250 mg, 3 or 4 times a day for 7 to 10 days.
Over 8 years: give 250 to 500 mg, 4 times a day for 7 to 10 days.
For severe infections, double the doses above.
Tetracycline and Doxycycline
Tetracycline and doxycycline are broad-spectrum antibiotics and fight many different kinds of bacteria. They work well when given by mouth (and are very painful when injected, so they should not be given that way). There are more infections that are now resistant to these medicines so they are not used as much as they once were, but they are still useful for fighting some infections.
Doxycycline and tetracycline can be used interchangeably. But doxycycline is usually a better choice because less is needed each day and it has fewer side effects.
Heartburn, stomach cramps, diarrhea, and yeast infections are common.
- Pregnant women should not take these medicines, as they can damage or stain the baby’s teeth and bones. For the same reason, children under 8 years old should take them only when there is no other effective antibiotic, and for short periods only. You can usually use erythromycin instead.
- Some people may develop a skin rash or get easily sunburned after spending time in the sun while taking these medicines, so stay out of the sun or wear a large hat.
TETRACYCLINE
Avoid milk, iron pills, and antacids for 2 hours before or after taking tetracycline. They will make the medicine less effective.
Take tetracycline on an empty stomach, at least 1 hour before or 2 hours after meals.
For most infections
dose by age:
8 to 12 years: give 125 mg, 4 times a day for 7 to 10 days.
Over 12 years: give 250 to 500 mg, 4 times a day for 7 to 10 days.
DOXYCYCLINE
Doxycycline is taken twice a day (instead of 4 times a day like tetracycline).
Avoid iron pills, and antacids for 2 hours before or after taking Doxycycline. They will make the medicine less effective.
Take doxycycline with plenty of water. It may be taken with food or milk if it upsets your stomach.
For most infections
8 to 12 years: give 50 mg twice a day, for 7 to 10 days.
Over 12 years: give 100 mg twice a day, for 7 to 10 days.
For animal bites, give the dose above for 3 to 5 days. Also give metronidazole or clindamycin.
Cotrimoxazole, sulfamethoxazole with trimethoprim, TMP-SMX
Cotrimoxazole, a combination of 2 antibiotics is inexpensive and fights a wide range of infections. It is an important medicine for people with HIV and can prevent the many infections that come as a result of HIV infection. See HIV and AIDS (in development).
Avoid giving cotrimoxazole to babies less than 6 weeks old and to women in the last 3 months of pregnancy. Allergy to this medicine is common. Signs of allergic reaction are fever, difficulty breathing, or rash. Stop giving cotrimoxazole if the person develops a rash or if you think there may be an allergy.
Cotrimoxazole comes in different strengths of each of the 2 medicines it contains. So it may say 200/40 (meaning 200 mg sulfamethoxazole and 40 mg trimethoprim) or 400/80 or 800/160. Sometimes a dose is described only in terms of the amount of trimethoprim (the second number).
For most infections
6 months to 5 years: give sulfamethoxazole 200 mg + trimethoprim 40 mg, 2 times a day 5 days.
6 to 12 years: give sulfamethoxazole 400 mg + trimethoprim 80 mg, 2 times a day 5 days.
Over 12 years: give sulfamethoxazole 800 mg + trimethoprim 160 mg, 2 times a day 5 days.
For animal bites, give the amount above for 3 to 5 days. Also give metronidazole or clindamycin.
Clindamycin
Clindamycin is another antibiotic used to treat many kinds of bacterial infections. It is especially useful for treating infections that have become resistant to penicillin such as skin infections and abscesses.
If you develop diarrhea that is watery or bloody while taking clindamycin, stop taking it immediately. This can be a sign of dangerous infection caused by the antibiotic. Because the drug can pass through breast milk and harm a baby, avoid giving to a breastfeeding woman.
Under 3 years: give 37.5 to 75 mg, 3 times a day.
3 to 7 years: give 75 to 150 mg, 3 times a day.
8 to 12 years: give 150 to 300 mg, 3 times a day.
Over 12 years: give 150 to 450 mg, 3 times a day.
For animal bites, give the dose above for 3 to 5 days. Also give another medicine such as doxycycline, cotrimoxazole OR penicillin V.
For an infected wound, give the dose above for 5 to 7 days.
For a burn that is infected, give the dose above for 5 to 7 days. If it is a deep burn, or the person also has a fever, give the dose above for 10 to 14 days.
For a bone that has broken through the skin (open fracture), give the dose above for 5 to 7 days. If the wound is very dirty, also give ciprofloxacin.
For knife or gunshot wound, give the dose above for 10 to 14 days.
Metronidazole
Metronidazole is effective at fighting certain bacteria and infections used by itself or in combination with other antibiotics.
Nausea, cramps, and diarrhea are common. Taking with food may help. Sometimes it causes a metallic taste in the mouth or a headache.
Do not give in the first 3 months of pregnancy because it may cause birth defects. Also avoid giving metronidazole later in pregnancy and while breastfeeding unless it is the only effective medicine and is definitely needed. Do not drink alcohol while taking metronidazole or until 2 days after you finish taking it. Drinking alcohol while taking metronidazole causes severe nausea. Do not use metronidazole if you have liver problems.
Under 1 year: give 37 mg, 4 times a day.
1 to 5 years: give 75 mg, 4 times a day.
6 to 12 years: give 150 mg, 4 times a day.
Over 12 years: Give 500 mg, 3 or 4 times a day. Do not give more than 4 g in 24 hours.
For an infected wound, give the dose above for 5 to 7 days. Also give dicloxacillin OR cephalexin.
For a wound likely to be infected with tetanus, along with medicines to prevent tetanus, antibiotics are sometimes given. For example, give the dose above for 7 to 10 days.
For animal bites, give the dose above for 3 to 5 days. Also give another medicine such as doxycycline, cotrimoxazole, OR penicillin V .
For a bone that has broken through the skin (open fracture), give the dose above for 5 to 7 days. Also give ceftriaxone, cephalexin OR cloxacillin.
Ciprofloxacin
Ciprofloxacin is a broad spectrum antibiotic of the quinolone family. It works against a lot of different infections of the skin, bones, digestive tract, and urinary tract (bladder and kidneys). There are more infections becoming resistant to ciprofloxacin depending on where you live. Only use it only against the infections for which it is specifically recommended in your area. It is not a good antibiotic for children.
Nausea, diarrhea, vomiting, headache, dizziness, rash, or yeast infections.
- Do not use if you are pregnant or breastfeeding. Do not take with dairy products such as milk or cheese.
- Rarely, ciprofloxacin damages the tendons. Except for a few specific situations, it should not be given to children under 16 because their tendons are still developing. If you have pain in your calves when taking this medicine, stop taking it immediately.
For most infections
For sepsis, give the dose above for 2 to 3 days after signs of infection are gone. Also give clindamycin.
For a bone that has broken through the skin (open fracture), give the dose above for 5 to 7 days. Also give clindamycin.
For a burn that is infected, give the dose above for 5 to 7 days. If it is a deep burn, or the person also has a fever, give the dose above for 10 to 14 days.
Ceftriaxone
Ceftriaxone is in the cephalosporin antibiotic family. Cephalosporins are antibiotics that work against many kinds of bacteria. They are often expensive and not widely available. However, they generally have fewer risks and side effects than many other antibiotics and can be useful in treating certain serious diseases.
Ceftriaxone is used against serious infections including sepsis and meningitis, and for infections resistant to penicillin. Only use ceftriaxone to treat the specific infections for which it is recommended in your area.
Ceftriaxone is especially useful for gonorrhea, including gonorrhea infection of the newborn’s eyes but otherwise should not be given to newborns under 1 week old and should be avoided in babies under 1 month old.
Do not give this medicine to someone who is allergic to other cephalosporin antibiotics.
Do not give to a baby less than 1 week old, except as treatment for gonorrhea in the eyes.
dose by age:
1 month to 3 months: inject 150 mg, twice a day.
3 months to 1 year: inject 250 mg, twice a day.
2 to 4 years: inject 400 mg, twice a day.
5 to 12 years: inject 625 mg, twice a day.
Over 12 years: inject 1 to 2 grams, once a day. Do not give more than 4 grams in 24 hours.
For a bone that has broken through the skin (open fracture), give the dose above for 5 to 7 days. If the wound is dirty, also give metronidazole.
For sepsis, give the dose above until 2 to 3 days after signs of infection are gone. If the wound is dirty, or there is no improvement 24 hours after starting ceftriaxone, also give metronidazole.
Cephalexin
Cephalexin is in the cephalosporin antibiotic family. Cephalosporins are antibiotcs that work against many kinds of bacteria. They are often expensive and not widely available. However, they generally have fewer risks and side effects than many other antibiotics and can be useful in treating certain serious diseases.
Diarrhea that is watery or bloody, fever, sore throat, headache, red skin rash with blistering or peeling, dark colored urine, confusion or weakness.
Under 6 months: give 100 mg, 4 times a day.
6 months to 2 years: give 125 mg, 4 times a day.
3 to 5 years: give 250 mg, 4 times a day.
6 to 12 years: give 375 mg, 4 times a day.
Over 12 years: give 500 mg, 4 times a day.
For an infected wound, give the dose above for 5 to 7 days. If the wound is very dirty, also give metronidazole.
For a burn that is infected, give the dose above for 5 to 7 days. If it is a deep burn, or the person has a fever, give the dose above for 10 to 14 days.
For a bone that has broken through the skin (open fracture), give the dose above for 5 to 7 days. If the wound is very dirty, also give metronidazole.
For knife or gunshot wound, give the dose above for 10 to 14 days. If the wound is dirty or in the abdomen, also give metronidazole.
Gentamicin
Gentamicin is a very strong antibiotic of the aminoglycoside family. It can only be given by injection or IV (in the vein). This drug can damage the kidneys and the hearing, so it should only be used in emergencies.
Gentamicin must be given in the exactly correct dose. Giving too much can cause kidney damage or permanent deafness. It is best to dose by weight. And do not give gentamicin for more than 10 days.
Inject into the muscle or the vein.
For sepsis
Over 12 years: inject 1 to 1.7 mg per kg, 3 times a day.