How Long Does Doxycycline Stay In Your System

How long does doxycycline stay in your system?

The length of time doxycycline stays in the body depends on many factors like age, genetics, the amount taken, metabolism, kidney and liver functions as well. The effects does not fade off immediately you take the drug, it takes hours for your system to clear out doxycycline. 

This drug is used for treating varieties of health conditions. In fact, there are many uses of doxycycline that the side effects are much as well. In this article, we will explain the meaning and uses of doxycycline, how it works and how to use it, and how long it will last in your system.

WHAT IS DOXYCYCLINE?

Doxycycline is a broad-spectrum antibiotic that prevents the growth of many bacteria. It is classified under the group of antibiotics known as tetracycline. It can treat many infections caused by bacteria and also others with parasitic origin. Doxycycline can also treat sexually transmitted infections like syphilis and systematic infections like pneumonia. 

Doxycycline is not recommended to be used by pregnant women or young children as it can cause yellowish discoloration of the teeth. Doxycycline was created and developed clinically in the early 1960s by Pfizer Inc., New York, NY, and marketed under the brand name Vibramycin. The drug was approved by the Food and Drug Administration (FDA) in 1967 making it the first once-a-day broad-spectrum antibiotic by Pfizer.

USES OF DOXYCYCLINE

Doxycycline is used to treat:

  • Infections caused by bacteria like pneumonia
  • Respiratory tract infections
  • Some skin and eye infection
  • Infections affecting the intestines, genitals, urinary and lymphatic system
  • Infections spread by infected animals, ticks, mites, lice, contaminated food and water
  • Acne alongside other medications
  • Anthrax (in people who must have been vulnerable to the infection in the air)
  • Plague and tuleramia
  • Malaria (prevention in this case)
  • Certain food poisoning in cases where penicillin cannot be used
  • Pimples and bumps caused by rosacea.

HOW DOES DOXYCYCLINE WORK?

Doxycycline treats infections by inhibiting the growth and spread of bacteria in the body. To treat acne, this drug works by killing bacteria that infect pores and decrease a natural oily substance that causes acne. Doxycycline also blocks the production of a bacterial protein, it does this by attaching itself to certain units of the protein, this prevents the protein from growing while treating your infections. Doxycycline treats rosacea by reducing the inflammation responsible for this skin condition.

HOW LONG DOES DOXYCYCLINE STAY IN YOUR SYSTEM AFTER YOUR LAAT DOSE?

Every person has a body feature and mechanism that is unique to them, these factors will influence the length of time doxycycline stays in your system.

How Long Does Doxycycline Stay In Your System
How Long Does Doxycycline Stay In Your System

Some factors that are considered when understanding how long doxycycline stays in the system are:

Age: Being young affects how the body breaks down substances. The younger you are, the more productive your body mechanism will be. The faster your body functions are, the faster doxycycline will be removed from your system.

Amount: The dose taken will affect the length of time the drug stays. If you take higher dose of doxycycline, the longer it will take for the drug to be removed.

Genetics: Genetics make it likely for people to have different body mechanism and function, this is an important component in how the body breaks down substances. This is why your genetics influences how doxycycline stays in the system.

Liver and Kidney Functions: These organs are responsible for breaking down everything you take in including doxycycline. If you have any issue with your liver or kidney, it will take a longer time for doxycycline and other substances to be removed from your system.

Metabolism: Your body’s metabolism are the chemical reactions in your cells that process foods, drinks and medications. The metabolism is responsible for how quickly your body acts on substances. If your metabolism is slow, doxycycline will stay in your body longer than someone with a fast metabolism.

Usage Frequency: Using doxycycline for a long time will make it to stay longer in your system. If you have been taking doxycycline for many months or even years, it will take your system a long time to eliminate it from your system than someone who has only been taking Doxycycline for a few months.

Approximately, doxycycline stays for 5 days before it is removed from the system. The elimination half-life of doxycycline for a healthy adult between 16 to 22 hours. This is the length of time it takes for your body to reduce the plasma levels by half. Before a drug is completely removed from the system, it usually take around 5.5 x elimination half-life. 

Since the half-life of doxycycline is 22 hours, it would take 121 hours (that is 22 hours divided by 5.5) which is approximately 5 days before the drug is removed from the system.

WHAT IS THE HALF LIFE OF DOXYCYCLINE?

The half-life of doxycycline is between 16 to 22 hours with the average being 18 hours although this can vary by many factors. This means after every 18 hours, the drug level drops in half. After it reaches to 4 or 5 half lives, the drug reaches its steady state. So, after 90 hours or 4 days, your body will reach the maximum level for any dose you are taking. This means that even if you take it for 3 weeks or years, it will be at the same level (unless your body changes how it breaks down medications).

Assuming the level of doxycycline in your body is 100 percent the day you stopped taking the drug, this is how the level will go down:

  • 18 hours – 50 percent
  • 36 hours – 25 percent
  • 54 hours – 12.5 percent
  • 64 hours – 6.125 percent
  • 82 percent – 3.0625 percent
  • 100 hours – 1.531 percent
  • 118 hours – 0.765

So in 4 days, you have less than 1 percent of doxycycline left in your body. On the fifth day, the drug will be completely eliminated.

HOW SHOULD DOXYCYCLINE BE USED?

Doxycycline comes in different forms like tablets, delayed-release tablets, capsules, delayed-release capsules and suspension. This drug is recommended to be taken either once or twice a day, each dose should be taken with a full glass of water. If you experience stomach upset when you take doxycycline, you can take the drug with food or milk. However, taking milk or food with doxycycline will reduce the amount of medication your stomach will absorb.

Stick to the recommended dosage from your doctor. Read the instructions on the product label carefully and take the drug as directed. Do not take less or more than prescribed.

The delayed-release capsules and capsules should be swallowed; do not crush or chew them. If the delayed-release tablets cannot be swallowed, you can break the tablet carefully and sprinkle the contents on a spoonful of applesauce (make sure the applesauce is warm or cold, not hot). Swallow the mixture without chewing, throw away the mixture of you cannot eat it immediately.

If you are using doxycycline to prevent malaria, take the drug at least a day or two before travelling to an area vulnerable to malaria. While you are still in the area, continue to take the drug each day and 4 weeks after leaving the place. Finish the dose but do not take the drug to prevent malaria for more than 4 months. Stick to the type of doxycycline prescribed by your doctor and do not substitute it with another type.

SIDE EFFECTS OF DOXYCYCLINE

There are side effects of doxycycline, some are common while others serious.

The common side effects of doxycycline are:

  • Diarrhea
  • Loss of appetite
  • Rash
  • Nausea and vomiting
  • Hives
  • Sensitivity to sun
  • Temporary yellowish discoloration of the teeth (this can be cleaned by a dentist after using the drug)

Serious side effects of doxycycline are:

  • Fever
  • Dehydration
  • Blood in stool
  • Severe diarrhea
  • Weight loss
  • Loss of appetite
  • Pain and cramps in the stomach
  • High blood pressure
  • Headache
  • Blurry vision
  • Double vision
  • Loss of vision
  • Pain in the chest
  • Ulcers in the esophagus
  • Irritation of the esophagus if you usually take the drug during bedtime
  • Anemia
  • Pain in the upper abdomen
  • Peeling of the skin
  • Blisters
  • Small purple spots on the skin

The common side effects may go away on their own after some time. If you notice they are not going away after some time or any of the serious side effects, see a doctor immediately.

DOXYCYCLINE INTERACTIONS WITH OTHER DRUGS

Doxycycline may interact with other vitamins, herbs, medications you may be taking with it. This can lead to decrease in the effect of either drug or cause adverse side effects.

You should not use doxycycline with these drugs like:

  • Penicillin as it will interfere with how the penicillin kills bacteria.
  • Isotretinoin – Combining doxycycline and Isotretinoin will increase your chances of having intracranial hypertension.
  • Warfarin

Some drugs when taken with doxycycline can reduce the effects of the doxycycline making it difficult to treat your condition.

Some of these drugs are:

  • Seizure drugs like carbamazepine, phenytoin and barbiturates
  • Antacids with calcium, bismuth subsalicylate, aluminum, and magnesium.

CONCLUSION

Doxycycline can stay in the system for up to 5 days before it is removed or cleared out. There are factors that can influence the length of time like your genetics, age, usage frequency, metabolism, liver and kidney functions. Doxycycline can interact with some drugs so you should consult your doctor before use.

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