How long does azithromycin keep working after last dose

Dosage and strength

Azithromycin tablets come as either 250mg or 500mg strengths. The capsules are 250mg. The liquid comes as 200mg in 5ml.

Table of Contents Show

Dosage and strength
Important: Important
How to take it
If you forget to take it
If you take too much

The usual dose is 500mg a day for 3 to 10 days depending on the infection being treated.

For some infections, you'll be given a one-off higher dose of 1g or 2g.

The dose may be lower for children or if you have liver or kidney problems.

Azithromycin is sometimes prescribed long-term to prevent chest infections if you keep getting them. In this case you will usually need to take it 3 times a week, often on a Monday, Wednesday and Friday.

Important: Important

Carry on taking this medicine until the course is completed, even if you feel better. If you stop your treatment early, your infection could come back.

How to take it

You'll usually take azithromycin once a day. Try to take your medicine at the same time each day.

Swallow tablets and capsules whole with a drink of water. If you are taking azithromycin capsules, take them at least 1 hour before food or 2 hours after eating. If you have tablets or liquid, you can take them with or without food.

The liquid can have a bitter aftertaste, so it can be a good idea to offer children a drink of fruit juice afterwards.

Do not take medicines for indigestion 2 hours before or after you take this medicine.

Azithromycin liquid is available for children and people who find it difficult to swallow tablets.

If you, or your child, are taking azithromycin as a liquid, your pharmacist will usually make it up for you. The medicine will come with a syringe or spoon to help you measure the right amount. If you do not have one, ask your pharmacist for one. Do not use a kitchen teaspoon as it will not measure the right amount.

If you forget to take it

If you forget to take a dose, take it as soon as you remember, unless it's nearly time for your next one. In this case, just leave out the missed dose and take your next dose at the usual time.

Never take 2 doses at the same time. Never take an extra dose to make up for a forgotten one.

If you often forget doses, it may help to set an alarm to remind you. You could also ask your pharmacist for other ways to help you remember to take your medicine.

If you take too much

Taking an extra dose of azithromycin is unlikely to harm you or your child. It may, however, increase the chance of temporary side effects, such as feeling or being sick or diarrhoea.

Talk to your pharmacist or doctor if you're worried, or if you or your child take more than 1 extra dose.

Many of you have read recent press reports regarding a study that concluded that the commonly used antibiotic called azithromycin, the “Z-Pak”, is associated with an increase in cardiovascular death. Ouch! Really? Since this study was published in the New England Journal of Medicine, it is probably worth a closer look.

Expert Opinion: The traditional method used by the press to address a controversial question like this is to trot out a celebrity doctor, like Dr. Oz (a former cardiovascular surgeon) or Fox’s Dr. Samadi (a celebrity urologist). However, given that these doctors are celebrity surgeons, who spend most of their time in other areas, it is probably not wise to look to the television set to sort this out.

What is a Z-Pak: The Z-pak is a 5 day course of an erythromycin type drug called azithromycin. The drug has a wider spectrum than traditional erythromycin, and hence kills lots of nasty bugs. The drug also stays in your system for about 10 days, which allows you to take a brief course of therapy to treat even serious infections.

Because of the drug’s chemical make-up, it is very effective in treating community acquired pneumonia. It is also very useful in treating atypical pneumonias – diseases like Legionnaire’s Disease, as well as COPD exacerbations, sinus infections and even resistant traveler’s diarrhea in the Far East, which has become unresponsive to drugs like Cipro.

Looking at the Details: To get to the real risks, you really have to look at the numbers in a study like this. You have to examine the absolute risk of sudden cardiac death associated with taking a Z-Pak to determine whether the potential benefits in a given situation are worth the risk.

This is the point that many people will simply allow their eyes to glaze over and will want to flip back to the T.V. channel with one of those celebrity doctors. Most people don’t want to examine the numbers…they just want the bottom line. “So really, Doc, is this drug going to kill me or not?” Instead of answering you directly, see if you can stay with me for a moment and slog through the numbers:

First: It is estimated that doctors wrote over 55-million prescriptions for a Z-Pak last year. Regardless of the risks of taking the drug, one of our first conclusions should be that doctors write too many of these prescriptions! Do we really need to treat 1 in 6 Americans every year with a Z-Pak? Doubtful. Doctors will write unnecessary prescriptions for antibiotics for lots of reasons: They may want to get a demanding patient out of their office, they may not understand the risks of using any antibiotic, or they may just be a little behind on their reading. For example, unless you have COPD, you do not need an antibiotic for most cases of bronchitis. Most ear infections, especially in children, clear without antibiotics.

Second: The study showed that taking the Z-Pak increased your risk of sudden cardiac death by 2½ times that of taking amoxicillin! So, if a simpler drug like amoxicillin will do for a simple infection, there is no reason to use a Z Pak.

Third: And perhaps most important, the risk of sudden death from taking a Z-Pak is extremely low! The absolute risk of sudden cardiac death attributed to a Z-Pak is 47 in 1,000,000 prescriptions, which translates into a risk of 0.005%. Put another way, you have a 99.995% chance of not suffering sudden cardiac risk by taking this drug.

Specific People Who Should Not Take a Z-Pak: Drugs like the Z-Pak, Levaquin and other antibiotics can increase the risk of sudden cardiac death in people who are taking drugs for heart arrhythmias. The risk of sudden cardiac death is also higher in people with known heart disease – higher than the 0.005% cited above.

Summary: Since you’ve been so kind in suffering through these numbers with me, I’ll now play the role of Dr. Oz and give you my summary points:

Do not take a Z-Pak without talking to me first. Some of my patients buy this drug in Mexico, or take it from friends or family members without consulting with me first. In general, this is not a good idea.
Do not be tempted to use the Z-Pak or other antibiotics for stubborn viral infections. Despite the widespread understanding that antibiotics do nothing to treat viral infections, or prevent bacterial infections from developing after a cold, some folks claim that they “always get better faster if they take an antibiotic.” Try to resist this temptation. The only case where this does not apply is in people with COPD, who do much better when antibiotics are started early for any lung infections.
If you take a medication for arrhythmias, for problems like atrial fibrillation, ALWAYS talk to me or to your cardiologist before taking an antibiotic – just to make sure that there are no drug-drug interactions that might increase your risk of sudden cardiac death.
Remember, the risk of taking a Z-Pak is extremely low. The media has hyped this story because the headlines get attention. However, when given in the right setting to the right person, the Z-Pak is an excellent drug, with an extremely low risk of complications. If you had the opportunity to bet some money in Las Vegas, with the chance of winning of 99.995%, you’d take this bet every time.