Doxycycline vs. amoxicillin: Uses, cost, side effects, and more

In this article:

• What are the main differences between doxycycline and amoxicillin?
• Conditions treated
• Efficiacy
• Cost and insurance coverage
• Side effects
• Interactions and warnings

In this article

• What are the main differences between doxycycline and amoxicillin?
• Conditions treated
• Efficiacy
• Cost and insurance coverage
• Side effects
• Interactions and warnings

Bacterial infections are common, with mild to serious and even life-threatening symptoms. However, they are entirely curable with the right antibiotics. If you experience a bacterial respiratory or urinary tract infection, among other infections, you may be prescribed an antibiotic, such as doxycycline or amoxicillin. 

Doxycycline and amoxicillin are generic antibiotics commonly prescribed for various bacterial infections. As generic options, they are accessible and typically covered by insurance and Medicare. However, they should only be used with the guidance of a healthcare provider or doctor. These antibiotics may differ in how they work and what they’re used for.

What are the main differences between doxycycline and amoxicillin?

Doxycycline and amoxicillin are both broad-spectrum antibiotics, meaning they can target a wide range of bacteria. However, they belong to different classes and have distinct properties.

How they work

Doxycycline belongs to the tetracycline class of antibiotics. It works by blocking protein synthesis in bacteria, effectively stopping their growth. Amoxicillin, on the other hand, is a penicillin-type antibiotic. It works by disrupting the formation of bacterial cell walls, leading to the death of bacteria.

There are two main forms of doxycycline: doxycycline monohydrate and doxycycline hyclate. Doxycycline monohydrate tends to be less irritating to the gastrointestinal tract compared to doxycycline hyclate, which can cause more stomach upset in some individuals. However, both forms are equally effective in treating bacterial infections.

Dosage and dosage forms

Doxycycline is commonly available in several forms, such as capsules, oral suspensions, and delayed-release tablets. Depending on the infection, it is typically taken as a 100 mg tablet twice daily for seven to ten days or longer.

Amoxicillin is also available in various forms, including capsules, oral suspensions, and chewable tablets. It is generally prescribed in dosages that depend on the type and severity of the infection. For adults, a common amoxicillin dosage is 500 mg every eight hours or 875 mg every 12 hours for seven to 14 days.

A healthcare provider will determine the exact duration and dosage of these antibiotics based on the infection and the individual’s medical history.

 

Main differences of Doxycycline vs. amoxicillin
	Doxycycline	Amoxicillin
Drug class	Tetracycline antibiotic	Penicillin antibiotic
Brand/generic status	Brand and generic versions available	Brand and generic versions available
What is the brand name?	Vibramycin Doryx Adoxa Monodox Oracea	Amoxil Moxatag Trimox Dispermox
What form(s) does the drug come in?	Oral tablet Oral delayed-release tablet Oral capsule Oral suspension	Oral tablet Oral tablet, chewable Oral capsule Oral suspension
What is the standard dosage?	Dosage depends on the infection being treated	Dosage depends on the infection being treated
How long is the typical treatment?	Duration depends on the infection being treated	Duration depends on the infection being treated
Who typically uses the medication?	Adults and children	Adults and children

Conditions treated by doxycycline and amoxicillin 

Doxycycline and amoxicillin both treat bacterial infections. They are ineffective against viral, parasitic, or fungal infections and should only be used with guidance from a healthcare provider. 

Doxycycline

Doxycycline is used to treat various infections, including:

• Tick-borne illnesses, such as Rocky Mountain spotted fever, typhus fever, Q fever, and other tick-related fevers
• Respiratory infections caused by Mycoplasma pneumoniae
• Sexually transmitted infections, such as Lymphogranuloma venereum, psittacosis, and uncomplicated urethral, endocervical, or rectal infections caused by Chlamydia
• Eye infections, such as inclusion conjunctivitis
• Urinary infections, such as nongonococcal urethritis
• Other infections, such as relapsing fever, chancroid, plague, tularemia, cholera, brucellosis, bartonellosis, and granuloma inguinale

Doxycycline also treats infections caused by certain bacteria, like:

• Gram-negative bacteria: E. coli, Enterobacter, Shigella, Acinetobacter, and Haemophilus influenzae
• Gram-positive bacteria: Streptococcus pneumoniae and Bacillus anthracis (anthrax)

Doxycycline can also help treat severe acne and prevent malaria in travelers.

Amoxicillin

Amoxicillin treats various bacterial infections, including:

• Ear, nose, and throat infections caused by Streptococcus, Streptococcus pneumoniae, Staphylococcus, or Haemophilus influenzae
• Urinary tract infections caused by E. coli, Proteus mirabilis, or Enterococcus faecalis
• Skin infections caused by Streptococcus, Staphylococcus, or E. coli
• Respiratory infections caused by Streptococcus, S. pneumoniae, Staphylococcus, or Haemophilus influenzae

For adults, amoxicillin also treats H. pylori infections and duodenal ulcers when combined with other drugs like clarithromycin and lansoprazole.

Doxycycline and amoxicillin should only be used to treat infections caused by bacteria to prevent drug-resistant bacteria and ensure antibiotics remain effective. Healthcare providers may use culture and susceptibility information to choose the right antibiotic. 

Is doxycycline or amoxicillin more effective?

Doxycycline and amoxicillin are both effective antibiotics. The most effective antibiotic will depend on the specific bacteria causing the infection. For example, amoxicillin may be an effective antibiotic for bacterial infections that are not resistant to penicillin. In some cases, doxycycline may be an appropriate option for some penicillin-resistant infections. 

One study involving 267 patients found that both doxycycline and amoxicillin were generally effective in treating respiratory infections, with only 7 out of 134 patients on doxycycline and 13 out of 133 patients on amoxicillin not improving. 

Another study examined the effectiveness of two different antibiotic treatments for people with H. pylori-related stomach ulcers. It found that using doxycycline or amoxicillin, along with other medications, led to high success rates in getting rid of the bacteria, with around 85% success in both treatment groups. Both treatments were also safe, with only 9 out of 184 participants experiencing mild side effects.

A healthcare provider should determine the most effective medication for a patient, given the patient’s medical condition, history, and current medications.

Doxycycline vs. amoxicillin: Insurance coverage and cost comparison

Doxycycline and amoxicillin are generic medications typically covered by most commercial insurance and Medicare plans. As generic drugs, they may be more accessible than similar brand-name drugs.

Without insurance coverage, the cash price of these antibiotics can vary. Different factors, such as pharmacy location and the quantity prescribed, can affect the overall price. SingleCare coupons may help reduce out-of-pocket costs. SingleCare’s coupon pages for doxycycline and amoxicillin offer discounts that may be used at participating pharmacies. 

	Doxycycline	Amoxicillin
Typically covered by insurance?	Yes	Yes
Typically covered by Medicare Part D?	No	Yes
Quantity	14 100 mg tablets	21, 500 mg capsules
Typical Medicare copay	Varies based on plan, copay. and deductible structure	Varies based on plan, copay. and deductible structure
SingleCare cost	$9	$6

Common side effects of doxycycline and amoxicillin 

Like other antibiotics, doxycycline and amoxicillin may commonly cause gastrointestinal side effects, such as nausea, vomiting, and diarrhea. In addition, both antibiotics may cause similar side effects, such as rash, tooth discoloration, and dizziness. Each drug can cause some unique side effects as well. For instance, doxycycline may cause photosensitivity. This means that individuals taking doxycycline should be cautious about sun exposure, as it can increase the risk of sunburn. Below is a list of the most common side effects for each antibiotic.

Doxycycline:

• Diarrhea
• Nausea
• Rash
• Vomiting
• Photosensitivity
• Tooth discoloration
• Dizziness
• Esophageal ulcers
• Decreased appetite

Amoxicillin:

• Diarrhea
• Nausea
• Rash
• Vomiting
• Headache
• Tooth discoloration
• Dizziness

Frequency is not based on data from a head-to-head trial. This may not be a complete list of adverse effects that can occur. Please refer to your doctor or healthcare provider to learn more.

Source: DailyMed (Doxycycline), DailyMed (Amoxicillin)

Doxycycline and amoxicillin drug interactions and warnings

Doxycycline and amoxicillin each interact with other drugs and supplements, but their interactions do vary. Doxycycline tends to have more drug interactions to be considered when prescribing. Dairy products, antacids, and supplements that contain calcium, iron, magnesium, or sodium bicarbonate can reduce the drug’s effectiveness by binding to it in the gastrointestinal tract. Doxycycline should be taken at least two hours apart from these substances. Barbiturates and certain anticonvulsants may decrease the half-life of doxycycline, causing doxycycline to be eliminated from the body more quickly. As a result, the effectiveness of doxycycline could be reduced because it won’t stay in the body as long as expected. Amoxicillin can have a negative effect on blood thinners like warfarin, increasing the risk of bleeding. This type of interaction can be fatal.

This list is some of the more common interactions you should be concerned with for each antibiotic:

Doxycycline:

• Antacids such as Maalox, Tums, or Milk of Magnesia
• Iron supplements
• Barbiturates such as phenobarbital
• Anticonvulsants such as phenytoin and carbamazepine
• Oral contraceptives

Amoxicillin:

• Anticoagulants such as warfarin
• Gout relief drugs such as probenecid and allopurinol
• Oral contraceptives

This may not be a complete list of all possible drug interactions. Consult a doctor about all medications you may be taking.

Doxycycline and amoxicillin have other precautions you should be aware of before taking. Patients with a medical history of allergies should be cautious with both antibiotics. Doxycycline and amoxicillin can cause severe allergic reactions like rash, itching, and anaphylaxis. If you have taken an antibiotic in the same class previously and experienced a reaction, you should not take these medications.

Severe skin reactions such as Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) can occur with both doxycycline and amoxicillin, though they are rare. Symptoms include blistering, peeling skin, and sores on mucous membranes. If you notice unusual skin changes or rashes, stop taking the medication and seek emergency care. In addition, both doxycycline and amoxicillin can cause Clostridioides difficile-associated diarrhea (CDAD), which is a potentially severe condition. Symptoms include severe diarrhea, abdominal pain, and fever. If you experience these symptoms while taking either antibiotic, contact your healthcare provider immediately.

Consult a healthcare provider for other warnings and precautions before using an antibiotic.