SUMMARY CMI

FOSCAVIR^®

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 FOSCAVIR?

FOSCAVIR contains the active ingredient foscarnet sodium. Foscavir is used to treat infections caused by two viruses, Cytomegalovirus (CMV) and Herpes simplex virus (HSV).

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

2. What should I know before I use FOSCAVIR?

Do not use if you have ever had an allergic reaction to foscarnet sodium or any of the ingredients listed at the end of the CMI.

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 FOSCAVIR? in the full CMI.

3. What if I am taking other medicines?

Some medicines may interfere with Foscavir 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 FOSCAVIR?

• Foscavir is diluted, then injected slowly into a vein in your arm or leg by a doctor or nurse. If you are in hospital, it may be injected into a major vein where it does not need to be diluted.
• The initial course of treatment is over 2-3 weeks. For CMV retinitis there will be two stages to your treatment. To treat Herpes Simplex virus, there is only one stage to treatment.

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

5. What should I know while using FOSCAVIR?

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

6. Are there any side effects?

If you get any of the following side effects, tell your doctor or nurse immediately or go to Accident and Emergency at your nearest hospital: shortness of breath, wheezing or difficulty breathing, swelling of the face, tongue or other parts of the body.

Tell your doctor or nurse if you have any of the following and they worry you: feeling or being sick, diarrhoea or constipation, stomach pain, indigestion, inflammation of the oesophagus – maybe painful. Feeling weak or tired, headache, decreased appetite, swelling due to fluid build up in the feet or legs or other parts of the body, swelling, pain or inflammation at injection site, generally feeling unwell. Genital discomfort and sores. Hives, skin rash or itching. High temperature or chills, signs of other infections. Feeling depressed, confused, anxious, nervous, agitated or aggressive. Co-ordination problems, reduced feeling in the skin, pathological alteration of the brain, shaking (tremors). Increased thirst and dry mouth. Painful, sore, weak or twitching muscles. Changes in blood test results, infections, high temperature (fever) and, feeling tired or looking pale. Bruising more easily. High blood pressure.

Tell your doctor or nurse immediately if you notice any of the following: Rash, itching or hives of the skin. Skin lesions or sores, red or purple rash that rapidly spreads, blisters of the skin and mucous membranes, swelling of the lips, face or throat. Fast, slow, pounding or irregular heart beats or a change in rhythm. Tingling or numb feeling, fits or seizures. Severe pain in your abdomen, vomiting blood or material that looks like coffee grounds, blood in the stools or black bowel motions. Swelling and redness along a vein, feeling dizzy. A change in the colour or the amount of urine you produce, or pain when urinating – maybe with lower back pain. Weakness, cramps, thirst, tingling or itching of the skin and twitching of muscles, rapid breathing.

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

FOSCAVIR^®

Active ingredient: foscarnet sodium

Consumer Medicine Information (CMI)

This leaflet answers some of the common questions people ask about Foscavir. It does not contain all the information that is known about Foscavir. It does not take the place of talking to your doctor or pharmacist. 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 Foscavir.

Where to find information in this leaflet:

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

1. Why am I using FOSCAVIR?

Foscavir contains the active ingredient foscarnet sodium.
Foscavir belongs to a group of medicines called antivirals. It is injected into the body where it interferes with the way viral cells reproduce themselves and stops them increasing in number.

Foscavir is used to treat infections caused by two viruses, Cytomegalovirus (CMV) and Herpes simplex virus (HSV).
These viruses infect different parts of the body and are most serious if your body's natural defences to fight disease are low (immunocompromised).

Your doctor will have explained what type of infection you have and where it is.

Foscavir is not addictive.

It is only available with a doctor's prescription. There is not enough information to recommend the use of Foscavir in children.

2. What should I know before I use FOSCAVIR?

Warnings

Do not use Foscavir if:

• you are allergic to foscarnet sodium or any of the ingredients listed at the end of this leaflet.
• always check the ingredients to make sure you can use this medicine.
• you are on haemodialysis. There is insufficient information on the use of Foscavir in patients undergoing haemodialysis.

If you are not sure whether you should be given Foscavir, talk to your doctor or nurse or pharmacist.

Check with your doctor if you:

• have or have had any other medical conditions:
  - any kidney disease or impairment
  - low calcium or magnesium levels in your blood
  - the need to control your sodium intake.
  It may not be safe for you to use Foscavir if you have these conditions. Your doctor may do blood and urine tests before and during your treatment with Foscavir. This is to check how well your kidneys are working and the level of minerals in your blood.
• take any medicines for any other condition

During treatment, you may be at risk of developing certain side effects. It is important you understand these risks and how to monitor for them. See additional information under Section 6. Are there any side effects?

Pregnancy and breastfeeding

Tell your doctor before you are given Foscavir if you are pregnant, intend to become pregnant, are breastfeeding or intend to breastfeed.

• Foscavir is not recommended during pregnancy.
• Trying to become pregnant during Foscavir therapy is not recommended so you should use effective contraception methods.
• Men treated with Foscavir should not father a child during or up to 6 months after therapy.
• Do not have Foscavir if you are breastfeeding.

3. What if I am taking other medicines?

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

Some medicines and Foscavir may interfere with each other. These include:

• certain medicines used to treat infections such as intravenous pentamidine, amphotericin, aminoglycoside antibiotics (e.g. gentamicin, streptomycin) or aciclovir.
• protease inhibitors (e.g. ritonavir, saquinavir)
• certain diuretics which are used to help reduce fluid and treat blood pressure such as frusemide
• ciclosporin, methotrexate or tacrolimus used to help prevent transplant rejection

These medicines may be affected by Foscavir or may affect how well it works.

Check with your doctor or pharmacist if you are not sure about what medicines, vitamins or supplements you are taking and if these affect Foscavir.

4. How do I use FOSCAVIR?

How much is given

Foscavir will be diluted with glucose 5% or normal saline, then injected slowly into a vein in your arm or leg by your doctor or nurse.

If you are in hospital, it may be injected into a major vein where it does not need to be diluted.

The dosage you will be given will depend on your body size, the infection you are being treated for, and how well your kidneys work.

How long to have it for

The initial course of treatment is over 2-3 weeks.

If you are being given Foscavir for CMV retinitis there will be two stages to your treatment.

If you are being given Foscavir to treat Herpes Simplex virus, there is only one stage to treatment.

If you forget to have FOSCAVIR

If you think you have missed a dose, talk to your doctor straight away.

If you use too much FOSCAVIR

The doctor giving you Foscavir will be experienced in its use, so it is unlikely that you will be given an overdose.

However, if you are particularly sensitive to Foscavir, or you are given too much you may get tingling or a numb feeling like "pins and needles", dizziness, fits or seizures. If you experience these symptoms, tell your doctor as soon as possible and your doctor will give you the appropriate treatment.

5. What should I know while using FOSCAVIR?

Things you must do

• Tell any other doctors, dentists and pharmacists who treat you that you are using Foscavir.
• Tell your doctor, dentist or pharmacist straight away that you are taking Foscavir if you are about to be started on any new medicine

Drink plenty of water while you are being given Foscavir.
You may notice changes in the frequency or amount of urine while you are on Foscavir treatment. Drinking plenty of water makes kidney problems such as these less likely. Any problems with your kidneys will usually return to normal when treatment is stopped.

Keep any appointments with your doctor.
Your doctor will want to monitor how this medicine is working and check for any side effects. They may do blood and urine tests to check how well your kidneys are working and the level of minerals in your blood.

Keep Foscavir solution and your urine away from your skin.
Foscavir is very irritating to the skin. As most of the drug is removed from the body in your urine, you should take special care to wash and dry yourself well after going to the toilet.

If you get Foscavir solution on your skin or in your eyes by mistake, rinse your skin or wash your eyes straight away with water.

Driving or using machines

Be careful before you drive or use any machines or tools until you know how Foscavir affects you.

Foscavir may cause dizziness, tiredness and fits or seizures in some people. If you have any of these symptoms, do not drive, operate machinery or do anything else that could be dangerous.

Looking after your medicine

Foscavir is stored in the pharmacy or ward. It is kept in a cool, dry place where the temperature stays below 25 degrees Celsius.

Getting rid of any unwanted medicine

Any Foscavir solution that is not used will be disposed of in a safe manner by your doctor, nurse or pharmacist.

6. Are there any side effects?

Tell your doctor or nurse or pharmacist as soon as possible if you do not feel well while you are being given Foscavir.

All medicines can have side effects. If you do experience any side effects, most of them are minor and temporary. However, some side effects may need medical attention.

See the information below and, if you need to, ask your doctor, nurse or pharmacist if you have any further questions about side effects.

Less serious side effects

Serious side effects

These may be serious side effects. You may need urgent medical attention.

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

Other side effects not listed here may occur in some people.

Reporting side effects

After you have received medical advice for any side effects you experience, you can report side effects to the Therapeutic Goods Administration online at www.tga.gov.au/reporting-problems. By reporting side effects, you can help provide more information on the safety of this medicine.

Always make sure you speak to your doctor or pharmacist before you decide to stop taking any of your medicines.

7. Product details

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

What FOSCAVIR contains

Do not take this medicine if you are allergic to any of these ingredients.

What FOSCAVIR looks like

Foscavir solution for injection is a clear, colourless solution containing foscarnet sodium 24 mg/mL as the active ingredient.

It comes in bottles of 250 mL. (AUST R 37310).

Who distributes FOSCAVIR

Link Medical Products Pty Ltd
5 Apollo St
Warriewood NSW 2102

This leaflet was prepared in August 2022

Foscavir^® is a trademark of Clinigen Healthcare Ltd

Published by MIMS February 2023

1 Name of Medicine

Foscarnet sodium hexahydrate.

2 Qualitative and Quantitative Composition

Intravenous infusion solution containing 6 g foscarnet sodium hexahydrate (24 mg/mL) in 250 mL.
A clear, sterile, isotonic solution of foscarnet sodium in Water for Injections, adjusted to pH 7.4 with hydrochloric acid. No preservatives or buffers are contained in Foscavir.
For the full list of excipients, see Section 6.1 List of Excipients.

3 Pharmaceutical Form

Solution for injection.

4 Clinical Particulars

4.1 Therapeutic Indications

Foscavir is indicated for:
treatment of cytomegalovirus (CMV) retinitis in patients with the acquired immunodeficiency syndrome (AIDS);
treatment of aciclovir resistant herpes simplex virus (HSV) infections (defined by clinical trial or in vitro resistance) in immunocompromised patients with human immunodeficiency virus (HIV) infection.

Note.

4.2 Dose and Method of Administration

Contact with the skin and eyes may cause local irritation and a burning sensation. If accidental contact occurs, the exposed area should be rinsed immediately with cold water.

Method of administration.

Adults.

Induction therapy.

Maintenance therapy.

Induction therapy.

Maintenance therapy.

Caution.

Hydration.

Duration of treatment.

Elderly.

Paediatric population.

Renal or hepatic impairment.

Compatibility.

4.3 Contraindications

Hypersensitivity to foscarnet.
Long-term treatment with foscarnet is contraindicated in patients with a reasonable prognosis (e.g. bone marrow transplant patients) because the animal toxicological data are limited and insufficient to ensure safety in man over an extended period.

4.4 Special Warnings and Precautions for Use

Co-administration with intravenous pentamidine.

Use in renal impairment.

Mineral and electrolyte abnormalities.

Genital irritation and ulceration.

Sodium content.

Diuretics.

Seizures.

Resistance.

Use in the elderly.

Paediatric use.

Effects on laboratory tests.

4.5 Interactions with Other Medicines and Other Forms of Interactions

1. A possible drug interaction of Foscavir and intravenous pentamidine has been described. Concomitant treatment of four patients in the United Kingdom with Foscavir and intravenous pentamidine may have caused hypocalcaemia; one patient died with severe hypocalcaemia. Toxicity associated with concomitant use of aerosolised pentamidine has not been reported.
Since Foscavir can reduce serum levels of ionized calcium, extreme caution is advised when used concurrently with other drugs known to reduce serum calcium levels, like IV pentamidine. Renal impairment and symptomatic hypocalcaemia (Trousseau's and Chvostek's signs) have been observed during concurrent treatment with foscarnet and IV pentamidine. Fatalities have been reported in post-marketing surveillance during concomitant therapy with Foscavir and pentamidine.
2. There is no pharmacokinetic interaction when foscarnet is used in combination with zidovudine (AZT), ganciclovir, didanosine (ddl), zalcitabine (ddC) or probenecid.
3. Since Foscavir can impair renal function, additive renal toxicity may occur when used in combination with other nephrotoxic drugs such as aminoglycosides, amphotericin B, ciclosporin A, aciclovir, methotrexate and tacrolimus.
4. Due to their mechanism of action, loop diuretics should not be used during Foscavir therapy.
5. Abnormal renal function has been reported in connection with the use of Foscavir in combination with ritonavir and/or saquinavir.
6. Pharmaceutical interactions (incompatibilities for infusion) are described in Section 6.2 Incompatibilities.

4.6 Fertility, Pregnancy and Lactation

Effects on fertility.

4.7 Effects on Ability to Drive and Use Machines

Foscarnet has no sedating effects and generally there is no reason to believe that the ability to drive or use machinery is impaired following the administration of foscarnet. However, adverse effects such as dizziness and convulsions may occur during therapy and the physician is advised to discuss this issue with the patient.

4.8 Adverse Effects (Undesirable Effects)

The majority of patients who receive Foscavir are severely immuno-compromised and suffering from serious viral infections. Patients' physical status, the severity of underlying disease, other infections and concurrent therapies contribute to adverse events observed during use of Foscavir.

Clinical trials experience.

Postmarketing and other experience.

Reporting suspected adverse effects.

4.9 Overdose

For information on the management of overdose, contact the Poisons Information Centre on 131126 (Australia).
Overdose has been reported during the use of Foscavir, the highest being some 20 times the recommended dose. Some of the cases were relative overdoses, in that the dose of the drug used had not been promptly adjusted for a patient experiencing reduced renal function. There are cases where it has been reported that no clinical sequelae occurred following the overdose.
The pattern of adverse events reported in association with overdose of Foscavir is in accordance with the known adverse event profile of the drug.
Haemodialysis increases foscarnet elimination and may be of benefit in relevant cases.

5 Pharmacological Properties

5.1 Pharmacodynamic Properties

Mechanism of action.

Clinical trials.

5.2 Pharmacokinetic Properties

Following IV administration in man, foscarnet plasma concentrations follow a multi-exponential decay pattern with several half-lives. The initial decline has a half-life of approximately 2-4 hours if renal function is normal. An apparent terminal half-life of approximately 1 to 8 days has been recorded, probably reflecting the slow release of foscarnet from bone.
The plasma clearance of foscarnet after intravenous administration to man varies between 130-160 mL/min. The mean volume of distribution of foscarnet at steady state varies between 0.4-0.6 L/kg.
Foscarnet is distributed to the cerebrospinal fluid and concentrations ranging from 10 to 70% of the concurrent plasma concentrations have been observed in HIV infected patients.
Foscarnet is mainly eliminated by the renal route, by glomerular filtration and tubular secretion. Renal clearance is approximately 130 mL/min.
There is no metabolic conversion of foscarnet, and the binding to human plasma proteins is less than 20%.
In man, up to 20% of the cumulative intravenous dose has not been excreted in the urine 7 days after cessation of infusion, and can be assumed to have been deposited in bone and cartilage. Deposition is greater in young and growing animals. This effect has only been seen in dogs.
The bone changes were characterised as increased osteoclast activity and bone resorption. The reason for these changes may be that Foscavir, due to its structural similarity to phosphate, is incorporated into the hydroxyapatite. Audioradiographic and other studies have shown Foscavir to have a pronounced affinity for bone tissue. Recovery studies revealed that bone changes were reversible. Foscarnet sodium has been demonstrated to adversely affect development of tooth enamel in mice and rats. The effects of this deposition on skeletal development have not been studied.
Following induction therapy, either administered as a continuous infusion or as intermittent infusions every eight hours, foscarnet has produced stabilisation of retinal lesions in approximately 90% of cases treated.
However, since CMV usually causes latent infections and since foscarnet, like other anti-CMV agents, exerts a virustatic effect, relapses are likely to be seen after therapy in the majority of patients with persistent immunodeficiency once treatment is discontinued.
Institution of once daily maintenance therapy following completion of induction therapy has produced a delay in time to retinitis progression. In patients experiencing progression of retinitis while receiving maintenance therapy or off therapy, re-institution of induction therapy has shown equal efficacy as the initial course.

Special populations - adults with impaired renal function.

5.3 Preclinical Safety Data

In several animal species foscarnet is rapidly cleared from blood and other soft tissues after intravenous administration. However, dose proportional concentrations have been observed in bone and cartilage in all animal species studied.
Investigations in dogs have shown that foscarnet has no effect on calcium homoeostasis.

Genotoxicity.

Carcinogenicity.

6 Pharmaceutical Particulars

6.1 List of Excipients

Water for injection, hydrochloric acid.

6.2 Incompatibilities

Foscavir is not compatible with glucose 30% solution, amphotericin B, aciclovir sodium, ganciclovir, pentamidine isethionate, trimethoprim/ sulfamethoxazole, vancomycin hydrochloride, or with solutions containing calcium. It is recommended that other drugs should not be infused concomitantly in the same line.

6.3 Shelf Life

In Australia, information on the shelf life can be found on the public summary of the Australian Register of Therapeutic Goods (ARTG). The expiry date can be found on the packaging.
Foscavir contains no preservative and once the sterility seal of a bottle has been broken the solution should be discarded within 24 hours.
For doses prepared by a hospital pharmacy, foscarnet may be transferred to plastic infusion bags for use within 24 hours.

6.4 Special Precautions for Storage

Store below 25°C. Do not refrigerate.

6.5 Nature and Contents of Container

Type I clear glass bottle.

6.6 Special Precautions for Disposal

In Australia, any unused medicine or waste material should be disposed of in accordance with local requirements.

6.7 Physicochemical Properties

Foscarnet sodium is trisodium phosphonoformate hexahydrate or phosphonoformic acid trisodium salt hexahydrate, MW 300.0.

Chemical structure.

CAS number.

7 Medicine Schedule (Poisons Standard)

Prescription Only Medicine (S4).

Summary Table of Changes