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Clindamycin vs Flagyl

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Clindamycin Information

Flagyl Information

Comparative Analysis

Clindamycin Usage

Flagyl Usage

Clindamycin Side Effects

Flagyl Side Effects

Safety Information

Cost Analysis

Market Analysis



For patients suffering from bacterial infections, certain antibiotics can help eliminate the harmful bacteria and alleviate symptoms. Clindamycin and Flagyl are two such drugs commonly prescribed for various bacterial infections. Both disrupt the processes essential to bacterial growth and survival but they each target different types of bacteria.

Clindamycin is a lincosamide antibiotic known for its effectiveness against serious skin and soft tissue infections caused by most staphylococcal strains. It works by blocking proteins that bacteria need to multiply.

Flagyl (metronidazole), on the other hand, is an antiprotozoal and antibacterial agent which acts primarily against anaerobic bacteria and parasites. It targets cells in an organism’s DNA structure, preventing it from producing new DNA molecules, thus leading to death of the cell.

It's important to note that both these antibiotics should only be used under prescription as their inappropriate use can lead to resistance or side effects such as upset stomach or diarrhea.

Clindamycin vs Flagyl Side By Side

Brand NameCleocinFlagyl
ContraindicationsSevere diarrhea or persistent nausea and vomiting, alcohol consumption, kidney disease, liver disease, pregnant women or those trying to conceive should consult their doctor.Severe diarrhea or persistent nausea and vomiting, alcohol consumption (avoid alcohol for at least 48 hours after finishing treatment), kidney disease, liver disease, pregnant women or those trying to conceive should consult their doctor.
CostBrand-name: around $120 for 60 tablets of 300 mg. Generic: as low as $0.70 per day depending on dosage and capsule quantity.Brand-name: roughly $50 for 30 tablets of 500 mg. Generic: starting at just over $0.40 per day based on typical dosages.
Generic NameClindamycinMetronidazole
Most Serious Side EffectSevere intestinal problems like pseudomembranous colitis caused by overgrowth of C.difficile bacteria.Neurological issues like seizures, mood changes, sight disturbances, heart-related problems.
Severe Drug InteractionsNot specified in the article, but generally includes drugs that may alter gut flora or those metabolized by the liver.Alcohol, resulting in disulfiram-like reaction; other drugs affecting liver metabolism.
Typical Dose150–450 mg every six hours; maximum dosage should not exceed 2700 mg/day.500-750 mg/day initially, can be increased to 1500-2250 mg/day, not to exceed 4 grams per day.

What is Clindamycin?

Clindamycin (also known under the brand name Cleocin) and Metronidazole (commonly referred to as Flagyl), are two different types of antibiotics used in treating a variety of bacterial infections. Clindamycin is part of the lincosamide class, whereas Metronidazole belongs to the nitroimidazoles class. Both were FDA approved in the 1960s—Clindamycin in 1966 and Metronidazole in 1963.

These drugs operate differently: Clindamycin prevents bacteria from creating proteins necessary for their growth, effectively stopping their proliferation. It's prescribed for treatment against serious respiratory tract, skin, soft tissue, and oral infections among others. On the other hand, metronidazole works by spreading into bacterial cells and interfering with their DNA repair function leading to cell death; it's commonly used against protozoal infections and anaerobic bacterial infections.

While both these medications have potential side effects such as nausea or diarrhea, clindamycin has more selective influence on certain types of bacteria resulting in fewer gastrointestinal side effects compared to metronidazole which may also cause a metallic taste sensation.

What conditions is Clindamycin approved to treat?

Clindamycin is approved for the treatment of various bacterial infections, including:

  • Serious respiratory tract infections such as empyema, lung abscess, and pneumonia
  • Skin and soft tissue infections
  • Severe pelvic inflammatory disease (in combination with a drug effective against Chlamydia trachomatis)
  • Bacterial septicemia
  • Intra-abdominal infections like peritonitis and intra-abdominal abscess (typically in conjunction with an appropriate surgical procedure)

How does Clindamycin help with these illnesses?

Clindamycin is an antibiotic that fights bacteria in the body by interfering with their ability to synthesize proteins, which are crucial for bacteria's growth and multiplication. It does this by binding to the subunit of a bacterial ribosome, thereby inhibiting protein synthesis and leading to bacterial cell death. Clindamycin is particularly effective against certain types of bacteria such as Staphylococcus aureus, Streptococcus pneumoniae, and other anaerobic bacteria.

Flagyl (metronidazole), on the other hand, works slightly differently but also aims at killing or stopping the growth of certain microbes. This drug disrupts DNA synthesis in susceptible organisms like protozoa and anaerobic bacteria causing them to die off.

Both antibiotics can be used for different infections; however, their antimicrobial spectra vary so it's important for healthcare providers to choose based on what organism they are attempting to treat.

What is Flagyl?

Flagyl, the brand name for metronidazole, is an antibiotic and antiprotozoal medication effective against anaerobic bacteria and certain parasites. It functions by inhibiting nucleic acid synthesis by disrupting DNA of microbial cells. This effect is typically bactericidal - it kills the bacteria.

Flagyl was first approved by the FDA in 1963. Although similar to clindamycin in its ability to treat bacterial infections, Flagyl does not inhibit protein synthesis as clindamycin does. Its unique mechanism of action means that its side-effect profile differs from that of other antibiotics such as clindamycin; notably, it may cause a metallic taste in the mouth and can interact with alcohol resulting in unpleasant effects such as nausea and flushing (known as "disulfiram-like reaction"). The unique properties of Flagyl make it particularly useful for treating gastrointestinal infections caused by certain types of bacteria and parasites which do not respond well to other antibiotics like Clindamycin.

What conditions is Flagyl approved to treat?

Flagyl, also known as Metronidazole, is a versatile medication that has been approved by the FDA for the treatment of several infections. These include:

  • Bacterial vaginosis: A condition characterized by an imbalance in vaginal bacteria.
  • Certain types of parasitic infections such as trichomoniasis and giardiasis.
  • Intra-abdominal infections caused by certain anaerobic bacteria.
  • Various skin and soft tissue infections.

How does Flagyl help with these illnesses?

Flagyl, also known as metronidazole, is a type of antibiotic that works by disrupting the DNA in bacteria and protozoa. It plays roles in many processes within these microorganisms, affecting their ability to reproduce and survive. As with other antibiotics, Flagyl can effectively treat a variety of infections caused by susceptible organisms including Bacteroides species, Fusobacteria, Clostridia, Eubacteria and some parasites. Its action on the cellular level helps to eradicate infection-causing bacteria from the body. Since it does not significantly affect gram-positive bacteria like Staphylococci or Streptococci (which Clindamycin targets), it is sometimes prescribed when a patient has an infection caused more specifically by anaerobic bacteria or certain parasites which are sensitive to metronidazole's mechanism of action.

How effective are both Clindamycin and Flagyl?

Both clindamycin and metronidazole (Flagyl) are well established in the treatment of anaerobic bacterial infections, with their initial FDA approvals only a few years apart. Given that they act on different processes within bacteria, they may be prescribed under varied circumstances. The effectiveness of both drugs in treating conditions like Bacterial Vaginosis has been directly studied; for instance, a 2004 double-blind clinical trial saw comparable efficacy between the two drugs. In this study, none of the metrics used to measure success in treating infection differed significantly between patients receiving clindamycin or metronidazole.

A 2011 review demonstrated that clindamycin is effective at alleviating symptoms from the first week of treatment, possesses an acceptable side effect profile compared to many other antibiotics and is generally well-tolerated even among pregnant women. Further studies show that it's frequently prescribed around the world due to its broad spectrum activity against various types of bacteria.

Meanwhile, a recent meta-analysis published in 2018 indicated that metronidazole seems more effective than placebo for certain infections such as Helicobacter pylori and is similar in efficacy to other common antibiotics for most uses. However, due to its potential side effects such as metallic taste and gastrointestinal upset which can affect patient compliance, it’s often considered after first-line treatments have been tried or ruled out.

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At what dose is Clindamycin typically prescribed?

Oral dosages of Clindamycin range from 150–450 mg every six hours, but studies have indicated that 150 mg every six hours is adequate for treating bacterial infections in most people. Children and adolescents may be started on a dose calculated by body weight (8-25mg/kg/day divided into three or four doses). In either population, dosage can be adjusted based on the severity of infection and patient's response to treatment after a few days. The maximum dosage that should not be exceeded in any case is 2700 mg/day.

At what dose is Flagyl typically prescribed?

Flagyl (metronidazole) treatment usually begins with a dosage of 500-750 mg/day, taken orally. This dose can then be increased to 1500-2250 mg/day, split into three doses and spaced approximately 8 hours apart. If there is no significant response to the treatment at this dosage after several weeks, your doctor may consider increasing the maximum dose up to 4 grams per day divided into smaller doses throughout the day but should not exceed this limit. As always, it's crucial for patients to consult their healthcare provider before making any adjustments in medication dosages or schedules.

What are the most common side effects for Clindamycin?

Potential side effects of clindamycin may include:

  • Nausea, vomiting, and stomach pain
  • Diarrhea (which can be severe)
  • Joint or muscle pain
  • Rash or itching
  • Heartburn and throat irritation
  • Metallic taste in the mouth when taking oral medication

In contrast, Flagyl (metronidazole) may cause:

  • Nausea, loss of appetite, and metallic taste in the mouth
  • Vomiting
  • Stomach cramps
  • Constipation or diarrhea
  • Dry mouth or strange tastes -Vaginal itching or discharge
    -Skin rash
    -Loss of balance/coordination.

Always consult with your healthcare provider for any persistent adverse effects.

abstract image of a patient experiencing side effect

Are there any potential serious side effects for Clindamycin?

Clindamycin and Flagyl are both antibiotics, but they are used to treat different types of infections and can have various side effects. Below are some potential issues you may experience while on these medications:

  • Severe skin reactions: blistering or peeling skin, rash, itching or hives
  • Troubles with breathing due to allergic reaction
  • Unusual bleeding or bruising
  • Symptoms of liver problems such as persistent nausea/vomiting, severe stomach/abdominal pain, yellowing eyes/skin
  • Changes in hearing (such as decreased hearing, ringing in the ears)
  • Signs of a new infection (e.g., fever, persistent sore throat).

If you're taking clindamycin and develop watery diarrhea that is severe or lasts more than 2 days stop using this drug immediately; it's an indication of a possible serious intestinal condition.

For those on Flagyl (metronidazole), be aware that consumption of alcohol may result in rapid heart rate(palpitations), redness under your skin, tingly feeling among others.

In any case where these symptoms appear whilst taking either medication seek immediate medical help.

What are the most common side effects for Flagyl?

Flagyl is known to cause certain side effects, including:

  • A metallic taste in the mouth
  • Nausea and vomiting
  • Upset stomach or loss of appetite
  • Diarrhea or constipation
  • Insomnia or other sleep problems
  • Dizziness or a feeling of unsteadiness
  • Dryness of the mouth and throat
  • Irritation, redness, or dry skin
  • Unusual urination patterns such as increased frequency.

While these are common side effects associated with Flagyl, not everyone experiences them. Furthermore, they often lessen over time as your body adjusts to the medication. However, if any persist or worsen significantly during treatment, it’s crucial to contact your healthcare provider promptly.

Are there any potential serious side effects for Flagyl?

While Flagyl (metronidazole) is generally well-tolerated, it can cause severe side effects in some individuals. Here are the symptoms to look out for:

  • Signs of an allergic reaction, including hives; difficulty breathing; swelling of the face, lips, tongue or throat
  • A burning sensation in eyes and skin pain accompanied by a red or purple rash that spreads - especially on face or upper body - causing blistering and peeling
  • Neurological issues like seizures (convulsions), numbness in hands and feet, dizziness
  • Mood changes such as confusion and unusual behavior patterns
  • Sight disturbances involving blurred vision, eye pain or seeing halos around lights
  • Heart-related problems featuring fast heartbeats or fluttering in your chest If you experience any of these symptoms while taking Flagyl, seek immediate medical attention.

Contraindications for Clindamycin and Flagyl?

Both Clindamycin and Flagyl, along with most other antibiotic medications, may cause disturbance in your digestive system. If you notice severe diarrhea or persistent nausea and vomiting while taking these medications, please seek immediate medical attention.

Neither Clindamycin nor Flagyl should be taken if you are consuming alcohol or have consumed it recently. Mixing these antibiotics with alcohol can lead to unpleasant side effects such as nausea, vomiting, flushing of the skin, tachycardia (rapid heartbeat), shortness of breath and even seizures. Always inform your physician about your drinking habits; avoiding alcohol for at least 48 hours after finishing a course of metronidazole (Flagyl) and 72 hours after finishing a course of tinidazole is generally advised to prevent adverse reactions.

It's worth noting that both drugs pose serious risks for individuals who have certain pre-existing conditions. For example, those with kidney disease or liver disease need to take special precautions when using either medication. Similarly, pregnant women or those trying to conceive should discuss potential risks with their doctor before starting on either clindamycin or flagyl.

How much do Clindamycin and Flagyl cost?

For brand-name versions of these drugs:

  • The price of 60 tablets of Clindamycin (300 mg) averages around $120, which works out to about $2 per day.
  • The price of 30 tablets for Flagyl (500 mg) is roughly $50, working out to approximately $1.67 per day.

Thus, if you are in the higher dosage range for Clindamycin (i.e., 900 mg/day), then brand-name Flagyl could be less expensive on a daily treatment basis. However, it is essential to remember that cost should not be a primary consideration in determining which drug is suitable for your condition.

For the generic versions of Clindamycin and Flagyl (Metronidazole), costs are significantly lower:

  • Generic Clindamycin can be found in packs ranging from 20 capsules up to hundreds with approximate costs starting as low as $0.70 per day depending on your dosage and capsule quantity.
  • Metronidazole also comes in varying pack sizes with prices starting at just over $0.40 per day based on typical dosages and size selection.

Please note that actual costs may vary depending upon factors like location, pharmacy choice or insurance coverage.

Popularity of Clindamycin and Flagyl

Clindamycin, available under brand names such as Cleocin, was prescribed to approximately 8.4 million individuals in the United States in 2020. Clindamycin is a lincosamide antibiotic and accounts for a significant percentage of antibiotics used to treat serious infections caused by anaerobes, especially when penicillins are not suitable. The prescription rate has been relatively steady over recent years.

Metronidazole, also known as Flagyl among other brands, was dispensed to about 10 million people in the USA during that same year. Metronidazole is considered one of the key medications within any health system according to World Health Organization’s List of Essential Medicines because it's effective against many kinds of bacterial infections including those caused by anaerobic bacteria and certain parasites; accounting for an important share in antibacterial prescriptions overall. Like clindamycin, its usage has remained fairly stable over the past decade.


Both Clindamycin and Flagyl (metronidazole) have a long history of usage in treating bacterial infections, supported by numerous clinical studies indicating their effectiveness. At times, these antibiotics may be combined for certain conditions; however, this should only be done under careful consideration by a physician due to potential drug interactions. Clindamycin primarily works against gram-positive bacteria and anaerobes while Flagyl is particularly effective against protozoans and anaerobic bacteria. Therefore, they tend to be prescribed based on the specific type of infection.

As generics are available for both drugs, significant cost savings can occur especially for patients paying out of pocket. Both Clindamycin and Flagyl require an appropriate duration of therapy to clear the infection completely; stopping treatment prematurely may not eliminate all bacteria.

The side effect profiles between the two drugs are similar with gastrointestinal effects such as nausea or diarrhea being common but generally well-tolerated issues in most instances. However, Clindamycin has been linked with more severe intestinal problems than Flagyl like pseudomembranous colitis caused by overgrowth of C.difficile bacteria. For both medications it's important that patients report any new or worsening symptoms immediately to their healthcare provider.