Consumer medicine information

Cephalex 250 mg and 500 mg

Cefalexin

BRAND INFORMATION

Brand name

Cephalex

Active ingredient

Cefalexin

Schedule

S4

 

Consumer medicine information (CMI) leaflet

Please read this leaflet carefully before you start using Cephalex 250 mg and 500 mg.

SUMMARY CMI

CEPHALEX 250 mg and 500 mg (Cephalexin BP 250 mg and 500 mg Capsules)*

Consumer Medicine Information (CMI) summary

The full CMI on the next page has more details. If you are worried about using this medicine, speak to your doctor or pharmacist.

1. Why am I using CEPHALEX?

CEPHALEX contains the active ingredients Cefalaxin monohydrate. CEPHALEX used to treat infections caused by bacteria in different parts of the body.

For more information, see Section 1. Why am I using CEPHALEX? in the full CMI.

2. What should I know before I use CEPHALEX?

Do not use if you have ever had an allergic reaction to CEPHALEX or any of the ingredients listed at the end of the CMI. Do not take CEPHALEX if you are pregnant, taking medicines similar to CEPHALEX or have serious allergic reaction to penicillin.

Talk to your doctor if you have any other medical conditions, take any other medicines, or are pregnant or plan to become pregnant or are breastfeeding.

For more information, see Section 2. What should I know before I use CEPHALEX? in the full CMI.

3. What if I am taking other medicines?

Some medicines may interfere with CEPHALEX and affect how it works.

A list of these medicines is in Section 3. What if I am taking other medicines? in the full CMI.

4. How do I use CEPHALEX?

  • Continue taking CEPHALEX 250 mg and 500 mg for as long as your doctor tells you.
  • It is important to complete the full course prescribed by your doctor, even if you begin to feel better after a few days. If you do not, the bacteria causing your infection may not clear completely or your symptoms may return.

More instructions can be found in Section 4. How do I use CEPHALEX? in the full CMI.

5. What should I know while using CEPHALEX?

Things you should do
  • Remind any doctor, dentist or pharmacist you visit that you are using CEPHALEX
  • Tell your doctor if you become pregnant while taking CEPHALEX.
Things you should not do
  • Do not take a double dose to make up for the dose that you missed.
  • Do not stop taking your medicine or change the dosage without first checking with your doctor.
Driving or using machines
  • CEPHALEX may cause dizziness or tiredness in some people.
Drinking alcohol
  • There are no known interactions between CEPHALEX and alcohol.
Looking after your medicine
  • Keep it in a cool dry place where the temperature stays below 30°C

For more information, see Section 5. What should I know while using CEPHALEX? in the full CMI.

6. Are there any side effects?

Common side effects include: dizziness, fainting, light-headedness, cough, headache, diarrhoea, feeling sick, stomach pain, tiredness, weakness. Serious side effects include: swelling of the face, lips, tongue and/or throat and difficulty breathing and/or swallowing. For more information, including what to do if you have any side effects, see Section 6. Are there any side effects? in the full CMI.



FULL CMI

CEPHALEX 250 mg and 500 mg (Cephalexin BP 250 mg and 500 mg Capsules)*

Active ingredient(s): (Cefalaxin monohydrate)


Consumer Medicine Information (CMI)

This leaflet provides important information about using CEPHALEX You should also speak to your doctor or pharmacist if you would like further information or if you have any concerns or questions about using CEPHALEX.

Where to find information in this leaflet:

1. Why am I using CEPHALEX?
2. What should I know before I use CEPHALEX?
3. What if I am taking other CEPHALEX?
4. How do I use CEPHALEX?
5. What should I know while using CEPHALEX?
6. Are there any side effects?
7. Product details

1. Why am I using CEPHALEX?

CEPHALEX 250 mg and 500 mg contains cephalexin monohydrate as the active ingredient. It is used to treat infections caused by bacteria in different parts of the body, including infections of the:

  • respiratory tract (throat, tonsils, chest and lungs)
  • nose (sinusitis)
  • ears (otitis media)
  • skin and soft tissue
  • kidneys and bladder (genitourinary tract).

This medicine belongs to a group of medicines called cephalosporins. These antibiotics work by killing the bacteria that are causing your infection.

Ask your doctor or pharmacist if you have any questions about why this medicine has been prescribed for you.

Your doctor may have prescribed it for another reason.

This medicine is available only with a doctor's prescription.

There is no evidence that it is addictive.

2. What should I know before I use CEPHALEX?

Warnings

When you must not take it

Do not take CEPHALEX 250 mg and 500 mg if you have an allergic reaction to:

  • any medicine containing cephalexin monohydrate
  • other cephalosporins
  • any of the ingredients listed at the end of this leaflet.

Do not take this medicine if you have had a serious allergic reaction to penicillin.

Some of the symptoms of an allergic reaction may include shortness of breath, wheezing or difficulty breathing; swelling of the face, lips, tongue or other parts of the body; rash, itching or hives on the skin.

Do not take this medicine after the expiry date printed on the pack or if the packaging is torn or shows signs of tampering.

If it has expired or is damaged, return it to your pharmacist for disposal.

If you are not sure whether you should start taking this medicine, talk to your doctor.

Before you start to take it

Tell your doctor if you are allergic to any other medicines or any foods, preservatives or dyes.

Tell your doctor if you have or have had any of the following medical conditions:

  • liver disease
  • kidney disease
  • bowel disease.

Tell your doctor if you are pregnant or plan to become pregnant or are breast-feeding.

Your doctor can discuss with you the risks and benefits involved.

If you have not told your doctor about any of the above, tell them before you start taking CEPHALEX 250 mg and 500 mg.

3. What if I am taking other medicines?

Taking other medicines

Tell your doctor or pharmacist if you are taking any other medicines, including any that you get without a prescription from your pharmacy, supermarket or health food shop.

Some medicines and CEPHALEX 250 mg and 500 mg may interfere with each other.

These include:

  • probenecid (e.g. Pro-Cid), a medicine commonly used to treat gout
  • metformin, a medicine used in the treatment of diabetes.

These medicines may be affected by CEPHALEX 250 mg and 500 mg or may affect how well it works. You may need different amounts of your medicines or you may need to take different medicines.

Your doctor or pharmacist has more information on medicines to be careful with or avoid while taking CEPHALEX 250 mg and 500 mg.

4. How do I use CEPHALEX?

Follow all directions given to you by your doctor or pharmacist.

They may differ from the information contained in this leaflet.

If you do not understand the instructions on the carton or bottle, ask your doctor or pharmacist for help.

How much to take

Your doctor will tell you how much and how often you should take CEPHALEX 250 mg and 500 mg.

This will depend on the type of infection. The dose varies from patient to patient.

How to take it

CEPHALEX 250 mg and 500 mg capsules: Swallow the capsules whole with a full glass of water.

When to take it

It does not matter if you take this medicine with or without food.

How long to take it

Continue taking CEPHALEX 250 mg and 500 mg for as long as your doctor tells you.

It is important to complete the full course prescribed by your doctor, even if you begin to feel better after a few days. If you do not, the bacteria causing your infection may not clear completely or your symptoms may return.

If you forget to take it

If it is almost time for your next dose, skip the dose you missed and take your next dose when you are meant to.

Otherwise, take it as soon as you remember, and then go back to taking your medicine as you would normally.

Do not take a double dose to make up for the dose that you missed.

If you are not sure what to do, ask your doctor or pharmacist.

If you have trouble remembering to take your medicine, ask your pharmacist for some hints.

If you take too much (overdose)

Immediately telephone your doctor or Poisons Information Centre (13 11 26) for advice, or go to Accident and Emergency at the nearest hospital, if you think you or anyone else may have taken too much CEPHALEX 250 mg and 500 mg. Do this even if there are no signs of discomfort or poisoning.

You may need urgent medical attention.

Symptoms of an overdose may include feeling sick in the stomach, diarrhoea, blood in the urine, unusually increased reflexes, convulsions or hallucinations.

5. What should I know while using CEPHALEX?

Things you must do

Tell your doctor if the symptoms of your infection do not improve within a few days or if they become worse.

Tell any other doctors, dentists and pharmacists who are treating you that you are taking CEPHALEX 250 mg and 500 mg, especially if you are about to be started on any new medicines.

Tell your doctor if you become pregnant while taking this medicine.

If you are about to have any blood tests, tell your doctor that you are taking CEPHALEX 250 mg and 500 mg.

It may interfere with the results of some tests.

If you are diabetic, check with your doctor or pharmacist before using urine sugar tests.

CEPHALEX 250 mg and 500 mg may affect the results of some of these tests.

Keep all of your doctor's appointments so that your progress can be checked.

Your doctor may do some tests from time to time to make sure the medicine is working and to prevent unwanted side effects.

Things you must not do

Do not take CEPHALEX 250 mg and 500 mg to treat any other complaints unless your doctor tells you to.

Do not give your medicine to anyone else, even if they have the same condition as you.

Do not stop taking your medicine or change the dosage without first checking with your doctor.

If you stop taking it, your condition may worsen.

Things to be careful of

Be careful driving or operating machinery until you know how CEPHALEX 250 mg and 500 mg affects you.

It may cause dizziness or drowsiness in some people. Children should be careful when riding bicycles or climbing trees.

6. Are there any side effects?

Tell your doctor or pharmacist as soon as possible if you do not feel well while you are taking CEPHALEX 250 mg and 500 mg.

This medicine helps most people with infection but it may have unwanted side effects in a few people.

All medicines have side effects. Sometimes they are serious, most of the time they are not. You may need medical attention if you get some of the side effects.

Ask your doctor or pharmacist to answer any questions you may have.

Tell your doctor if you notice any of the following and they worry you:

  • sore or white mouth or tongue (oral thrush)
  • sore and itchy vagina and/or discharge (another form of thrush)
  • diarrhoea
  • nausea
  • vomiting
  • dizziness
  • unusual tiredness/weakness
  • abdominal pain
  • headache.
  • severe body rash
  • swelling of face, lips, mouth, tongue or throat which may cause difficulty in swallowing or breathing
  • fever
  • swelling of the joints
  • yellowing of the skin or eyes
  • joint pain
  • confusion and hallucinations
  • seizure potential
  • bleeding or bruising more easily than normal.

The above list includes serious side effects which may require medical attention. Serious side effects are rare.

Tell your doctor immediately if you notice any of the following, particularly if they occur several weeks after stopping treatment with CEPHALEX 250 mg and 500 mg:

  • severe stomach cramps or pain
  • severe, watery or bloody diarrhoea
  • fever, in combination with one of the above.

Do not take any diarrhoea medicine without first checking with your doctor.

You may have a serious condition affecting your bowel requiring urgent medical attention.

Tell your doctor immediately or go to Accident and Emergency at your nearest hospital, if you notice any of the following:

  • sudden signs of allergy such as rash, itching or hives on the skin with swelling of the face, lips, tongue or other parts of the body, shortness of breath, wheezing or trouble breathing.

This is a very serious side effect. You may need urgent medical attention or hospitalisation. This side effect is very rare.

Tell your doctor or pharmacist if you notice anything else that is making you feel unwell.

Other side effects not listed above may also occur in some people. Some of these side effects can only be found when your doctor does tests from time to time to check your progress.

Do not be alarmed by this list of possible side effects. You may not experience any of them.

7. Product details

Storage

CEPHALEX 250 mg and 500 mg capsules:

Keep the capsules in the blister pack until it is time to take them.

If you take the capsules out of the blister pack, they may not keep as well.

Keep it in a cool dry place where the temperature stays below 30°C (for the 250 mg and 500 mg capsules).

Keep it where children cannot reach it.

A locked cupboard at least one¬and-a-half metres above the ground is a good place to store medicines.

Do not store it or any other medicine in the bathroom or near a sink. Do not leave it on a window sill or in the car.

Heat and dampness can destroy some medicines.

Disposal

If your doctor tells you to stop taking this medicine or the expiry date has passed, ask your pharmacist what to do with any medicine that is left over.

What it looks like

CEPHALEX 250 mg

White to off white powder filled in dark green cap and dark green body with printing "CEP" on cap and "250" on body with black ink. They are available in packs of 20 capsules.

CEPHALEX 500 mg

White to off white powder filled in light green cap and light green body with printing "CEP" on cap and "500" on body with black ink. They are available in packs of 20 capsules.

Ingredients

CEPHALEX 250 mg and 500 mg capsules:

Capsules:

CEPHALEX 250 mg and 500 mg capsules contain cephalexin (as monohydrate) equivalent to 250 mg or 500 mg of cephalexin anhyrdrous as the active ingredient.

They also contain the inactive ingredients:

  • Lactose Anhydrous
  • Silicon Dioxide
  • Magnesium Stearate

The capsule shell consists of titanium dioxide, allura red, brilliant blue, quinoline yellow, gelatin, sodium lauryl sulphate, and water. Traces of printing black Ink contain shellac, dehydrated alcohol, Isopropyl alcohol, butyl alcohol, propylene glycol, strong ammonia solution, black iron oxide, potassium hydroxide and water.

Sponsor

Pharmacor Pty Ltd.
Chatswood, NSW 2067,
Australia

Australian Registration Numbers for CEPHALEX 250 mg and 500 mg products are:
250 mg capsule: 204535
500 mg capsule: 204534

This leaflet was prepared on: July 2023

Published by MIMS October 2023

BRAND INFORMATION

Brand name

Cephalex

Active ingredient

Cefalexin

Schedule

S4

 

1 Name of Medicine

Cephalexin monohydrate.

2 Qualitative and Quantitative Composition

Cephalex 250 mg capsules.

Each capsule contains cephalexin (as monohydrate) equivalent to 250 mg cephalexin anhydrous.

Cephalex 500 mg capsules.

Each capsule contains cephalexin (as monohydrate) equivalent to 500 mg cephalexin anhydrous.

Excipients with known effect.

Lactose.
For the full list of excipients, see Section 6.1 List of Excipients.

3 Pharmaceutical Form

Cephalex 250 mg capsules.

Hard gelatin capsules size "2", body dark green and cap dark green with printing "CEP" on cap and "250" on body with black ink containing 250 mg cephalexin.

Cephalex 500 mg capsules.

Hard gelatin capsules size "0", body light green and cap light green with printing "CEP" on cap and "500" on body with black ink containing 500 mg cephalexin.

4 Clinical Particulars

4.1 Therapeutic Indications

Cephalexin is indicated in the treatment of the following infections when caused by susceptible strains of the designated microorganisms:
Respiratory tract infections caused by S. pneumoniae and group A beta-haemolytic streptococci. (Penicillin is the usual drug of choice in the treatment and prevention of streptococcal infections, including the prophylaxis of rheumatic fever. Cephalexin is generally effective in the eradication of streptococci from the nasopharynx; however, substantial data establishing the efficacy of cephalexin in the subsequent prevention of rheumatic fever are not available at present.)
Bacterial sinusitis caused by streptococci, S. pneumoniae and S. aureus (methicillin sensitive only).
Otitis media due to S. pneumoniae, staphylococci.
Skin and soft tissue infections caused by staphylococci and/or streptococci.
Genitourinary tract infections, including acute prostatitis caused by E. coli, P. mirabilis, and Klebsiella sp.
The effectiveness of cephalexin in the treatment of bacterial infections of the brain and spinal column has not been established and cephalexin is not indicated in these conditions.

Note.

Appropriate culture and susceptibility tests should be initiated prior to and during therapy to determine susceptibility of the causative organism to cephalexin. Renal function studies should be performed when indicated.

4.2 Dose and Method of Administration

Dosage.

The adult dosage ranges from 1 to 4 g daily in divided doses. The usual adult dose is 250 mg every 6 hours.
The usual recommended daily dosage for children is 25 to 50 mg/kg in divided doses.

Method of administration.

Cephalex 250 mg and 500 mg are administered orally.

Dosage adjustment.

Adults.

For streptococcal pharyngitis or tonsillitis, mild, uncomplicated urinary tract infections, and skin and soft tissue infections, a dosage of 500 mg may be administered every 12 hours.
For more severe infections or those caused by less susceptible organisms, larger doses may be needed. If daily doses of cephalexin greater than 4 g are required, parenteral cephalosporins, in appropriate doses, should be considered.
Twice daily dosing is not recommended when doses larger than 1 g daily are administered.

Children.

For streptococcal pharyngitis in patients over 1 year of age, tonsillitis, mild, uncomplicated urinary tract infection, and skin and soft tissue infections, the total daily dose may be divided and administered every 12 hours.
In severe infections, the dosage may be doubled.
In the therapy of otitis media, clinical studies have shown that a dosage of 75 to 100 mg/kg/day in 4 divided doses is recommended.
In the treatment of beta-haemolytic streptococcal infections, a therapeutic dosage of cephalexin should be administered for at least 10 days.

Impaired renal function.

See Section 4.4 Special Warnings and Precautions for Use.

4.3 Contraindications

Cephalexin is contraindicated in patients with known allergy to the cephalosporin group of antibiotics or who have previously experienced a major allergy to penicillin (see Section 4.4 Special Warnings and Precautions for Use).

4.4 Special Warnings and Precautions for Use

Before instituting therapy with cephalexin, every attempt should be made to determine if the patient has had previous hypersensitivity reactions to the cephalosporins, penicillins or other drugs. This product should be given cautiously to penicillin sensitive patients.
There is some clinical and laboratory evidence of partial cross allergenicity of the penicillins and the cephalosporins. Patients have been reported to have had severe reactions (including anaphylaxis) to both drugs.
If an allergic reaction to cephalexin occurs, the drug should be discontinued and the patient treated with the usual agents (e.g. adrenaline or other pressor amines, antihistamines or corticosteroids).
Antibiotic associated pseudomembranous colitis has been reported with virtually all broad spectrum antibiotics (including macrolides, semisynthetic penicillins and cephalosporins). A toxin produced with Clostridium difficile appears to be the primary cause. The severity of the colitis may range from mild to life threatening. It is important to consider the diagnosis in patients who develop diarrhoea or colitis in association with antibiotic use (this may occur up to several weeks after cessation of antibiotic therapy). Mild cases usually respond to drug discontinuation alone. However, in moderate to severe cases appropriate therapy with a suitable oral antibacterial agent effective against Clostridium difficile should be considered. Fluids, electrolytes and protein replacement should be provided when indicated.
Drugs which delay peristalsis, e.g. opiates and diphenoxylate with atropine (Lomotil) may prolong and/or worsen the condition and should not be used.
Broad spectrum antibiotics should therefore be prescribed with caution in individuals with a history of gastrointestinal disease, particularly colitis.
Patients should be followed carefully so that any side effects or unusual manifestations of drug idiosyncrasy may be detected.
Prolonged use of cephalexin may result in the overgrowth of nonsusceptible organisms. Careful observation of the patient is essential. If superinfection occurs during therapy, appropriate measures should be taken.

Seizure potential.

Several cephalosporins have been implicated in triggering seizures, particularly in patients with renal impairment when the dosage was not reduced. If seizures occur, discontinue Cephalex. Anticonvulsant therapy can be given if clinically indicated.

Use in renal impairment.

Cephalexin should be administered with caution in the presence of markedly impaired renal function. Careful clinical and laboratory studies should be made because safe dosage may be lower than that usually recommended.
Indicated surgical procedures should be performed in conjunction with antibiotic therapy.

Use in the elderly.

No data available.

Paediatric use.

No data available.

Severe cutaneous adverse reactions.

Severe cutaneous adverse reactions (SCAR), such as Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), drug reaction with eosinophilia and systemic symptoms (DRESS), and acute generalised exanthematous pustulosis (AGEP) have been reported in patients taking beta-lactam antibiotics. When SCAR is suspected, cephalexin should be discontinued immediately and an alternative treatment should be considered.

Effects on laboratory tests.

The quantitative determination of urinary protein excretion using strong acids is misleading during cephalexin therapy as precipitation of cephalexin in the urine may occur.
A false positive reaction for glucose in the urine may occur with Benedict's or Fehling's solution or with Clinitest.
Positive direct Coombs' tests have been reported during treatment with the cephalosporin antibiotics. In haematologic studies or in transfusion cross matching procedures when antiglobulin tests are performed on the minor side or in Coombs' testing of newborns whose mothers have received cephalosporin antibiotics before parturition, it should be recognised that a positive Coombs' test may be due to the drug.

4.5 Interactions with Other Medicines and Other Forms of Interactions

As with other β-lactams, the renal excretion of cephalexin is inhibited by probenecid.
In healthy subjects given single 500 mg doses of cephalexin and metformin, plasma metformin Cmax and AUC increased by an average of 34% and 24%, respectively, and metformin renal clearance decreased by an average of 14%. The interaction of cephalexin and metformin following multiple dose administration has not been studied. Administration of a cephalosporin to a metformin treated patient may result in increased metformin exposure.

4.6 Fertility, Pregnancy and Lactation

Effects on fertility.

No data available.
(Category A)
Cephalexin is excreted in the milk. Caution should be exercised when cephalexin is administered to a nursing woman. Alternative feeding arrangements for the infant should be considered.

4.7 Effects on Ability to Drive and Use Machines

The effects of this medicine on a person's ability to drive and use machines were not assessed as part of its registration.

4.8 Adverse Effects (Undesirable Effects)

Adverse drug reactions reported with cephalexin are very rare (< 0.01%) and are listed below:

Blood and lymphatic system disorders.

Eosinophilia, neutropenia, thrombocytopenia, haemolytic anaemia.

Gastrointestinal disorders.

Nausea, vomiting, diarrhoea, dyspepsia, abdominal pain.

General disorders and administration site conditions.

Fatigue.

Hepatobiliary disorders.

Cholestatic jaundice, transient hepatitis, elevated SGOT, elevated SGPT.

Immune system disorders.

Allergic reactions, urticaria, angioedema.
These reactions usually subsided upon discontinuation of the drug.
Anaphylaxis has also been reported.

Infections and infestations.

Pseudomembranous colitis.

Musculoskeletal and connective tissue disorders.

Joint disorder, arthralgia, arthritis.

Nervous system disorders.

Dizziness, headache, seizure potential.

Psychiatric disorders.

Hallucinations, agitation, confusion.

Renal and urinary disorders.

Reversible interstitial nephritis.

Reproductive and breast disorders.

Genital and anal pruritus, genital moniliasis, vaginitis, vaginal discharge.

Skin and subcutaneous tissue disorders.

Rash, erythema multiforme.
These reactions usually subsided upon discontinuation of the drug.
Severe cutaneous adverse reactions, including Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), drug reaction with eosinophilia and systemic symptoms (DRESS), and acute generalised exanthematous pustulosis (AGEP) have been reported in beta-lactam antibiotics.

Reporting suspected adverse effects.

Reporting suspected adverse reactions after registration of the medicinal product is important. It allows continued monitoring of the benefit-risk balance of the medicinal product. Healthcare professionals are asked to report any suspected adverse reactions a www.tga.gov.au/reporting-problems.

4.9 Overdose

There is no definite experience of poisoning or severe overdosage with cephalexin. However, clinical features of overdosage may be similar to those seen with other cephalosporins and penicillins, i.e. convulsions, hallucinations, hyper-reflexia, electrolyte imbalance, gastrointestinal disturbances and haematuria.
In the event of severe overdosage, general supportive care is recommended including close clinical and laboratory monitoring of haematological, renal, hepatic functions and coagulation status until the patient is stable.
Forced diuresis, peritoneal dialysis, haemodialysis or charcoal haemoperfusion have not been established as beneficial for an overdose of cephalexin.
For information on the management of overdose contact the Poisons Information Centre on 131126 (Australia).

5 Pharmacological Properties

5.1 Pharmacodynamic Properties

Mechanism of action.

In vitro tests demonstrate that the cephalosporins are bactericidal because of their inhibition of cell wall synthesis. Cephalexin 250 mg and 500 mg is active against the following organisms in vitro: beta-haemolytic streptococci; staphylococci, including coagulase positive, coagulase negative and penicillinase producing strains; Streptococcus (Diplococcus) pneumoniae; Escherichia coli; Proteus mirabilis; Klebsiella sp.

Note.

Most strains of enterococci (Enterococcus faecalis) and a few strains of staphylococci are resistant to cephalexin. It is not active against most strains of Enterobacter sp., Morganella morganii (formerly Proteus morganii) and Proteus vulgaris. It has no activity against Pseudomonas or Acinetobacter calcoaceticus (formerly Mima and Herellea sp.) When tested by in vitro methods, staphylococci exhibit cross resistance between cephalexin and methicillin type antibiotics.
Disc susceptibility. Dilution or diffusion techniques, either quantitative (MIC) or breakpoint, should be used following a regularly updated, recognised and standardised method (e.g. NCCLS). Standardised susceptibility test procedures require the use of laboratory control microorganisms to control the technical aspects of the laboratory procedures.
A report of susceptible indicates that the pathogen is likely to be inhibited if the antimicrobial compound in the blood reaches the concentrations usually achievable. A report of intermediate indicates that the result should be considered equivocal, and if the microorganism is not fully susceptible to alternative, clinically feasible drugs, the test should be repeated. This category implies possible clinical applicability in body sites where the drug is physiologically concentrated or in situations where high dosage of drug can be used. This category also provides a buffer zone, which prevents small uncontrolled technical factors from causing major discrepancies in interpretation. A report of resistant indicates that the pathogen is not likely to be inhibited if the antimicrobial compound in the blood reaches the concentrations usually achievable; other therapy should be selected.

Note.

The prevalence of resistance may vary geographically for selected species and local information on resistance is desirable, particularly when treating severe infections.
Minimal inhibitory concentration (MIC) breakpoints. See Table 1.

Clinical trials.

No data available.

5.2 Pharmacokinetic Properties

Absorption.

Cephalexin is acid stable and may be given without regard to meals. It is rapidly absorbed after oral administration.

Distribution.

Following doses of 250 mg, 500 mg, and 1 g, average peak serum levels of approximately 9, 18, and 32 microgram/mL, respectively, were obtained at 1 hour. Measurable levels were present 6 hours after administration.

Metabolism/ excretion.

Cephalexin is excreted in the urine by glomerular filtration and tubular secretion. Studies showed that over 90% of the drug was excreted unchanged in the urine within 8 hours. During this period, peak urine concentrations following the 250 mg, 500 mg, and 1 g doses were approximately 1000, 2200 and 5000 microgram/mL, respectively.

5.3 Preclinical Safety Data

Genotoxicity.

No data available.

Carcinogenicity.

No data available.

6 Pharmaceutical Particulars

6.1 List of Excipients

Lactose anhydrous, silicon dioxide, magnesium stearate.
The capsule shell consists of titanium dioxide, allura red, brilliant blue, quinoline yellow, gelatin, sodium lauryl sulphate, water.
Traces of printing black Ink contain shellac, dehydrated alcohol, isopropyl alcohol, butyl alcohol, propylene glycol, strong ammonia solution, black iron oxide, potassium hydroxide, water.

6.2 Incompatibilities

Incompatibilities were either not assessed or not identified as part of the registration of this medicine.

6.3 Shelf Life

36 months.

6.4 Special Precautions for Storage

Cephalex 250 mg: Store below 30 degrees Celsius.
Cephalex 500 mg: Store below 30 degrees Celsius.

6.5 Nature and Contents of Container

Cephalex 250 mg and 500 mg capsules are supplied in PVC/PVDC-Alu blister pack of 20 capsules.

6.6 Special Precautions for Disposal

In Australia, any unused medicine or waste material should be disposed of by taking to your local pharmacy.

6.7 Physicochemical Properties

Cephalexin monohydrate is a semisynthetic cephalosporin antibiotic for oral administration. It is 7-(D-α-amino-α -phenyl-acetamido)-3-methyl-3-cephem-4- carboxylic acid, monohydrate.

Chemical structure.

Cephalexin monohydrate has the following structural formula.
Mol. Formula: C16H17N3O4S.H2O.
Mol. Wt: 365.4.

CAS number.

23325-78-2.
The nucleus of cephalexin is related to that of other cephalosporin antibiotics. The compound is a zwitterion; i.e. the molecule contains both a basic and an acidic group. The isoelectric point of cephalexin in water is approximately 4.5 to 5.
The crystalline form of cephalexin which is available is a monohydrate. It is a white crystalline solid having a bitter taste. Solubility in water is low at room temperature; 1 or 2 mg/mL may be dissolved readily, but higher concentrations are obtained with increasing difficulty.
The cephalosporins differ from penicillins in the structure of the bicyclic ring system. Cephalexin has a D-phenylglycyl group as substituent at the 7-amino position and an unsubstituted methyl group at the 3 position.

7 Medicine Schedule (Poisons Standard)

Prescription Only Medicine (S4).

Summary Table of Changes