Keflex is an antibiotic that people use to treat a number of bacterial infections, but most commonly urinary tract infections, respiratory infections and ear infections.

Keflex also goes by another name, Cephalexin. Keflex is part of the List of Essential Medicines noted by the World Health Organisation.

What Is Keflex Used For?

In addition to this, the Food and Drug Administration (the FDA) has also approved Keflex to treat a whole host of other infections, some of which are listed below [1].

  • Urinary tract infections
  • Bone and joint infections
  • Respiratory tract infections, including things like pneumonia
  • Ear infections
  • Skin infections
  • Prostatitis
  • Strep throat
  • Tonsillitis

Whilst Keflex does a great job at fighting against the above illnesses, it is important to note that Keflex does not protect against MRSA infections or other viral infections, including the common cold or the common flu.

Antibiotics are never used to treat viral infections like these, and nor should they be.

Using antibiotics when you simply do not need to be taking them can cause damage, including an increase in tolerance and a greater risk of getting infected in the future.

If you were to abuse antibiotics in this way and suffer from an infection that did require antibiotics, they might no longer be effective.

How Does Keflex Work?

Keflex works by attacking the bacteria at the heart of your infection. To be more precise, Keflex attacks the gram-positive bacteria in your infection.

This means that it attacks strains of bacteria called Staphylococcus, Streptococcus and Pneumococcus.

Whilst it does a great job at attacking gram-positive bacteria, it also attacks against gram-negative bacteria such as Eschichia Coli, Proteus Miabrillis and other gram-negative bacteria. It is this type of bacteria that is responsible for lots of infections such as urinary tract infections [1].

Key facts about Keflex

There is an awful lot of information online about Keflex, which can make things seem quite confusing.

However, below is a list of the key facts you should know before taking Keflex:

  • When you take Keflex, it should take a few days in order to feel better, depending on the type of infection you are suffering from and how bad your infection is
  • There are a range of side effects from taking Keflex which are listed below
  • You can drink alcohol whilst taking Keflex although it is not recommended
  • You should only take Keflex if you have been prescribed the drug by a doctor
  • You should only take Keflex as prescribed to you and you should always stick to the recommended dosage

Does Alcohol Affect Keflex?

As mentioned above, Keflex is a form of antibiotic. Most people know that when you take antibiotics you are not supposed to drink alcohol. However, when it comes to Keflex it is not actually harmful to drink alcohol whilst you take Keflex, although it is not recommended.

Some people think that when you drink alcohol and take antibiotics, then the antibiotics no longer work the way they should. However, for some antibiotics, this simply is not the case.

However, you are definitely not allowed to drink alcohol when taking some antibiotics, as this could lead to respiratory problems and heart problems further down the line.

This is why you should always check with your local GP about whether you can or cannot drink alcohol when taking a particular type of antibiotic.

Nevertheless, drinking alcohol whilst taking Keflex will not affect you in this way. This does not mean that you should get drunk when taking an antibiotic such as Keflex.

This is because when taking Keflex, some people experience a range of side effects, similar to the side effects of drinking alcohol.

This includes excessive sweating, feeling or being sick, headaches and disorientation. This means that by mixing alcohol to your prescription you will only be making your symptoms worse.

It is also important to understand that when you mix alcohol with antibiotics, it might not only make you feel worse, but it will take you longer to actually recover from your illness. This is because alcohol affects your nervous system as well as your immune system which makes it difficult to get better, as well as more susceptible to picking up new infections and illnesses.

In addition to this, people who frequently abuse alcohol also damage their liver. This means that when your body tries to metabolise antibiotics such as Keflex, then you might find that you need more antibiotics than the average person in order to recover.

This could mean that you will need a higher or longer dosage in order to fully recover.

Most people are also prescribed Keflex because they are suffering from a urinary tract infection.  Unfortunately, drinking alcohol when suffering from a urinary tract infection can also make recovering from your infection much harder.

Alcohol will also increase your blood sugar and lower your overall energy levels, which makes it even harder for you to recover, even with the help of antibiotics such as Keflex.

Alcohol also has a huge impact on the immune system. This is mainly because alcohol causes a huge disruption to your sleeping pattern which means that your body isn’t getting enough rest to heal itself.

When recovering from an illness that requires antibiotics to recover, your body requires rest and recuperation in order to recover fully. Your body cannot do this if you are drinking heavily and spending the next few days feeling hungover, drained and tired.

Alcohol and UTIs

Whilst antibiotics such as Keflex are safe to use when drinking alcohol, if you are taking antibiotics to treat a urinary tract infection then drinking alcohol whilst suffering from this infection is not recommended.

It is important to remember that when you suffer from a urinary tract infection (a UTI) then you will need to drink a lot of water, to try to flush the infection out of your system. This means that you need to stay as hydrated and rested as possible.

However, most people know that alcohol dehydrates the body, and as a result it might take longer for your body to flush out the infection.

What Are the Risks of Drinking on Keflex?

Whilst there are no major risks of drinking alcohol whilst taking Keflex, it does have a huge impact on your body when it comes to other antibiotics. These side effects range from being common to more severe.

You might experience the following symptoms when combining antibiotics and alcohol:

  • Diarrhoea
  • Being sick
  • Feeling sick
  • Headaches
  • Feeling tired
  • Rashes
  • Struggling to sleep
  • High blood pressure

In addition to these above side effects and symptoms, individuals might also find that their illness isn’t going away as quickly as they would have hoped whilst still drinking.

General side effects of Keflex

A freckled woman in glasses, looking away

The main reason why you should avoid drinking alcohol whilst taking antibiotics such as Keflex is that Keflex comes with its own side effects, which can make recovering from your illness hard enough.

Some of the following side effects are common side effects that people experience when taking Keflex:

  • A poorly tummy
  • Struggling to go to the toilet (constipation)
  • Diarrhoea
  • Feeling tired for no real reason
  • Getting hot flushes
  • Headaches
  • Feeling short of breath
  • Bruising easily
  • Pale or yellow skin
  • Cold hands and feet
  • Pain when having a wee
  • Irregular heartbeats
  • Feeling weak

These side effects are common, but they are normal and usually go away on their own.

However, it is important to understand that there are a number of more serious side effects when it comes to Keflex.

These side effects are a lot less common than the above side effects and happen in less than 1 in every 1,000 people.

However, if you do experience any of the above side effects then you should seek medical help immediately:

  • Severe diarrhoea that lasts four or more days
  • Blood in your stool
  • Mucus in your stool
  • Pale stool or particularly dark urine
  • Yellowing of the skin
  • Bruised skin

It is also important to understand that there are a number of long-term side effects from consuming Keflex. It is important to understand that antibiotics are only ever prescribed for a certain amount of time, so that they do not do any long-term damage to your body.

Most antibiotics have a range of long-term side effects, which can result in some rather unpleasant illnesses.

For this reason, your doctor will always check with you to see if you are at risk of suffering from any long-term health issues, such as chronic UTI infections or prosthetic joint infections.

You might also become resident to certain antibiotics if you become resident to another antibiotic or drug in the same scientific class [3].

However, it is interesting to know that Keflex has a lower chance of antibiotic residence than other antibiotics such as Bactrim [4].

Call our helpline on: 0800 326 5559

What if I forget to take Keflex?

A woman taking a while pill

If you are drinking alcohol, or if you suffer from a substance use disorder whilst taking antibiotics such as Keflex, then you might find yourself forgetting to take your antibiotics every now and then.

However, forgetting to take your antibiotics won’t help you in the long or short term.

If you do forget to take a dose of Keflex due to alcohol, then you should try to take it again as soon as you remember to. However, you should not take your forgotten dose if it is nearly time for your next dose of Keflex. If this does happen, you should always skip your missed dose of Keflex and take your next scheduled dose as normal.

You should always wait at least four hours between taking your doses and never ever take two doses at the same time.

If you are frequently drinking alcohol and taking Keflex, then there are a number of things you can do, including setting an alarm to help you to remember to take your Keflex doses on time.

If you do find yourself taking too much Keflex, then it is important that you seek medical advice as soon as possible.

Call our helpline on: 0800 326 5559

Do People Abuse Keflex?

pill bottle and pills

Keflex is not considered a highly addictive drug. However, every drug has the ability to be abused by individuals. Keflex is most at risk of being abused when it comes to people who engage in IV drug use.

This is mainly because these people who are addicted to IV drugs find themselves more prone to catching a range of bacterial infections through the frequent use of injections.

This means that they will, unfortunately, get poorly more, and therefore require antibiotics more often, including Keflex. As this happens, your immune system will struggle to keep up, meaning that you might need to take more Keflex in order to get better.

In addition to this, people who drink a lot of alcohol are also more likely to abuse Keflex than people who are not addicted to alcohol.

How Does Alcohol Interact with Other Antibiotics?


If you are concerned about how Keflex interacts with antibiotics, then you might be interested to understand how other antibiotics interact with alcohol use. Whilst some antibiotics are fine to use whilst drinking alcohol, other antibiotics are not safe to drink whilst taking.


If you are taking metronidazole antibiotics, then you should not be consuming alcohol whilst taking them. In fact, alcohol should not be used within three days of completing Metronidazole.

This is because doing so would drastically increase the side effects you experience whilst taking alcohol. This is because Metronidazole will stop the alcohol from being broken down and passed easily through the body.


Cefotetan is another form of antibiotic which should not be mixed with alcohol. As with Metronidazole, if you do combine Cefotetan with alcohol then the side effects will be more severe.

You might also experience some unpleasant side effects including an increase in heart rate, red skin and excessive sweating.


Sulfamethoxazole is another type of antibiotic commonly prescribed to patients with bacterial infections throughout the UK.

Whilst individuals who are taking Sulfamethoxazole are allowed to drink alcohol, there are a number of side effects associated with doing so which would mean that it is not recommended.

This includes things like respiratory issues, feeling sick, red skin and excessive sweating.

Addiction Treatment for Alcohol Misuse & Addiction

Two people holding hands

If you are drinking alcohol whilst taking antibiotics, then you might need help and support from professionals. If you are suffering from a long-term alcohol addiction, then you will most likely need to attend inpatient or outpatient rehab in order to recover.

At rehab, you will be offered a range of different treatment options such as cognitive behavioural therapy, group therapy, family therapy and a range of aftercare and support services.

Cognitive Behavioural Therapy (CBT) for alcoholism

Cognitive behavioural therapy (also known as CBT) is a form of one-to-one talking therapy. During this form of therapy, you will work with a trained CBT therapist to get to the bottom of your addiction by looking at the causes and triggers of your addiction.

Cognitive behavioural therapy works to try to highlight the link between your thoughts, feelings and actions so that you can break the cycle of your own vicious thoughts.

Group Therapy for alcoholism

Group therapy is another type of treatment available to those with any type of addiction. During group therapy, you will work as a team with other people who are all also suffering from addictions to try to work together.

You will get to listen to other people’s stories and addiction issues, whilst being able to offer up advice and support. By doing this, you might be able to learn a thing or two about your own addiction issues.

Family Therapy for alcoholism

Lots of people who suffer from addiction issues also suffer from issues within the family unit. This is why a lot of rehab centres across the UK offer family therapy to their patients.

Your family members will be invited into your therapy sessions, and you will all work together closely with a therapist to get to the bottom of any triggers that may lay within the family unit.

Aftercare & Support Services for alcoholism

If you are struggling with a long term addiction issue, then you might want to engage in aftercare and support services. This includes things like self help groups, including Alcoholics Anonymous, Narcotics Anonymous and SMART meetings.

Speak to OK Rehab

If you are suffering from an addiction to alcohol and are struggling to overcome your addiction, then why not speak to a member of the team at OK Rehab?

OK Rehab is specialist in treatment options for a range of different addiction issues, and will be able to guide you on where to go to get the right kind of treatment for you and your addiction.

We work with over 140 different rehab centres across the UK, so OK Rehab will be able to recommend a rehab centre local to you and your family, so that you do not have to move far away in order to receive your treatment.

Start your treatment journey today by calling the team at OK Rehab on 0800 326 5559 or by visiting OK Rehab online at


[1] Food and Drug Administration. Package insert – Keflex (cephalexin) capsules.

[2] Herman TF, Hashmi MF. Cephalexin. In: StatPearls [Internet].

[3] Pouwels KB, Muller-Pebody B, Smieszek T, Hopkins S, Robotham JV.Selection and co-selection of antibiotic resistances among Escherichia coli by antibiotic use in primary care: an ecological analysis. PLoS ONE. 2019;14(6):e0218134. doi:10.1371/journal.pone.0218134

[4] Abduzaimovic A, Aljicevic M, Rebic V, Vranic S, Abduzaimovic K, Sestic S.Antibiotic resistance in urinary isolates of Escherichia coli. Mater Sociomed. 2016;28(6):416. doi:10.5455/msm.2016.28.416-419