Foscarnet (Intravenous)

Foscarnet is used to treat certain viral infections in patients who are suffering from acquired immune deficiency syndrome or other immunocompromising conditions.


Foscarnet is an injection that is given in the treatment of certain viral infections in cases where patients are immunocompromised. This can occur from the presence of infections such as acquired immune deficiency syndrome (AIDS) and other conditions which lower the immune system of the patient.

Commonly, Foscarnet is given in the treatment of cytomegalovirus (CMV) of the eye in patients who are suffering from age. This treatment will not cure the infection but it can help in controlling symptoms to prevent them from worsening.

Foscarnet may also be used to treat the herpes simplex virus (HSV) where patients are suffering from immunocompromising conditions.

Foscarnet can be used in the treatment of other serious viral infections as and when determined by a doctor. It cannot, however, be used for the treatment of all viruses. The common cold or flu, for example, will be unaffected by this treatment.

This medication should only ever be used under the direct supervision of a doctor.

Foscarnet is prescribed as a solution for injection as Foscavir.

Conditions Treated

  • Cytomealovirus (CMV)
  • Herpes simplex virus (HSV)
  • Other serious viral infections

Type Of Medicine

  • Antiviral

Side Effects

In addition to the required effects occurring from the use of Foscarnet, other unwanted effects can also occur. In some cases these side effects may require medical attention. Not all side effects may occur.

You should consult your doctor immediately if you experience these side effects following treatment with Foscarnet. These side effects may be indicators of more serious medical conditions that are developing and should not be ignored:

Occurring more commonly:

  • Changes in the frequency of urination or amount of urine produced
  • Increase in thirst

Occurring less commonly:

  • Chills
  • Convulsions or seizures
  • Feverishness
  • Muscle twitches
  • Numbness in hands or feet
  • Pain in hands or feet
  • Pain occurring at the site of injection
  • Tingling sensation or around the mouth
  • Tremor
  • Unusual tiredness
  • Unusual weakness

Occurring only rarely:

  • Sores or ulcers appearing on the:
  •  mouth
  •  penis
  •  throat
  •  vulva

Other side effects can also occur that do not normally require patients to seek medical attention. If you experience these common side effects you do not normally need to seek medical attention but you may do so if they become bothersome or are ongoing:

  • Abdominal pain
  • Confusion or disorientation
  • Decreased appetite
  • Dizziness
  • Feeling of anxiousness
  • Headaches
  • Nausea
  • Stomach pain
  • Unusual tiredness
  • Unusual weakness
  • Vomiting

Other side effects that have not been listed herein can also occur when you begin use of this medication. If you experience other side effects that are not listed then you should contact your doctor for advice.


You will be administered with this medication in a hospital. It will be injected by a nurse or doctor and is injected directly into a vein.

This medication should be injected slowly and will be administered over a period of 1-2 hours.

To prevent damage occurring to your kidneys you should consume extra liquid before, during and after treatment. You may also have additional liquids injected into your veins during this treatment to prevent damage from occurring.

To ensure that the best response to this medication is achieved you should ensure that you complete the full course of the treatment. It must be taken on a regular schedule so that a steady dose of Foscarnet can be maintained in the blood of the patient.

Foscarnet should be administered with infusions taking place every 8 hours for a period of 2-3 weeks. The dose given is usually 60mg/kg of body weight for CMV treatment and 40mg/kg for HPV treatment.


Foscarnet may interact with a wide range of medications. You must inform your doctor of all medications that you are taking before beginning use of this treatment. This includes all over the counter treatments, prescribed medications, dietary supplements and herbal remedies that you are taking. This is because some medications can interact violently with one another and cause potentially life-threatening results. In other cases, drugs may stop one another from working.

The use of Foscarnet in conjunction with the following medications is not recommended. Your doctor may decide not to use this treatment or may change other medications:

  • Ziprasidone
  • Thioridazine
  • Terfenadine
  • Sparfloxacin
  • Saquinavir
  • Probucol
  • Piperaquine
  • Pimozide
  • Mesoridazine
  • Levomethadyl
  • Dronedarone
  • Cisapride
  • Bepridil
  • Arsenic Trioxide
  • Amisulpride
  • Amifampridine

The use of Foscarnet would not normally be recommended with the following treatments. In some cases both medications may be required and your doctor may prescribe both with alterations to the dose or to the frequency of use:

  • Zuclopenthixol
  • Zotepine
  • Zolmitriptan
  • Vinflunine
  • Vemurafenib
  • Vasopressin
  • Vandetanib
  • Valacyclovir
  • Triptorelin
  • Trimipramine
  • Trimethoprim
  • Trifluoperazine
  • Torsemide
  • Tobramycin
  • Telithromycin
  • Tedisamil
  • Tacrolimus
  • Sultopride
  • Sulpiride
  • Sulfamethoxazole
  • Streptomycin
  • Spiramycin
  • Spectinomycin
  • Sotalol
  • Sisomicin
  • Sevoflurane
  • Sertindole
  • Sematilide
  • Risperidone
  • Quinidine
  • Quetiapine
  • Protriptyline
  • Propafenone
  • Prochlorperazine
  • Procainamide
  • Prajmaline
  • Pitolisant
  • Pirmenol
  • Pimavanserin
  • Pentamidine
  • Pazopanib
  • Pasireotide
  • Paromomycin
  • Panobinostat
  • Ondansetron
  • Octreotide
  • Nortriptyline
  • Netilmicin
  • Neomycin
  • Nafarelin
  • Moxifloxacin
  • Metronidazole
  • Methotrexate
  • Mefloquine
  • Lorcainide
  • Lidoflazine
  • Levofloxacin
  • Leuprolide
  • Ketoconazole
  • Kanamycin
  • Ivabradine
  • Isradipine
  • Isoflurane
  • Isepamicin
  • Imipramine
  • Ibutilide
  • Hydroxyzine
  • Hydroxychloroquine
  • Hydroquinidine
  • Histrelin
  • Halothane
  • Haloperidol
  • Halofantrine
  • Goserelin
  • Gonadorelin
  • Gentamicin
  • Gemifloxacin
  • Furosemide
  • Framycetin
  • Fluoxetine
  • Fluconazole
  • Flecainide
  • Ethacrynic Acid
  • Escitalopram
  • Erythromycin
  • Enflurane
  • Encainide
  • Efavirenz
  • Droperidol
  • Doxepin
  • Donepezil
  • Domperidone
  • Dolasetron
  • Dofetilide
  • Disopyramide
  • Dibenzepin
  • Dibekacin
  • Deslorelin
  • Desipramine
  • Delamanid
  • Degarelix
  • Dabrafenib
  • Cyclosporine
  • Crizotinib
  • Clarithromycin
  • Cidofovir
  • Chlorpromazine
  • Chloroquine
  • Chloral Hydrate
  • Capreomycin
  • Buserelin
  • Bumetanide
  • Bretylium
  • Azimilide
  • Astemizole
  • Aripiprazole
  • Aprindine
  • Anagrelide
  • Amphotericin B
  • Amoxapine
  • Amitriptyline
  • Amiodarone
  • Amikacin
  • Ajmaline
  • Acyclovir
  • Acecainide

Interactions can also occur between other medications and Foscarnet. You must inform your doctor of all medications you are taking to prevent the occurrence of drug interactions.

Medical conditions not being treated by this medication can also impact or be impacted by the use of Foscarnet. In some cases conditions may be worsened by use and in others there may be an increased risk of side effects. You must inform your doctor of all medical conditions that you suffer from before beginning use. This is particularly important if you suffer from any of the following conditions as they may be worsened by the use of Foscarnet:

  • Anemia
  • Electrolyte imbalance
  • Mineral imbalance
  • Granulocytopenia
  • Heart disease
  • Seizures

There may be an increased risk of more serious side effects occurring in patients with the following conditions:

Patients on a controlled diet to manage sodium intake should not be given a Foscarnet injection.

Other conditions could also impact use. Patients should inform their doctor of all medical conditions.


Before beginning treatment with Foscarnet, patients must consider the risks of use in relation to the benefits of using this treatment. You should make the decision to use it with your doctor having ensured that all of the following factors have been taken into account:

Allergies ' You must inform your doctor of any unusual reactions you have ever had to any medications in the past. Allergies to medications, dyes, preservatives, animals or other substances could prohibit the use of this treatment.

Pediatric ' The safety and efficiency of use in children have not been established. Foscarnet has not be tested in children.

Geriatric 'There have been no demonstrated limitations to the use of Foscarnet in elderly patients in appropriate studies performed to date. Elderly patients are more likely, however, to have certain age-related conditions that could limit the use of this treatment.

Pregnancy ' The risk to use during pregnancy has been categorized as a category C risk. This means that there may be a risk to the fetus from use during pregnancy. Patients must inform their doctor if they are pregnant before beginning use of this treatment. Patients should avoid becoming pregnant during use and should discuss pregnancy with their doctor.

Breastfeeding  No appropriate studies have been performed to date on the relationship between this treatment and the impact on nursing infants. You should discuss this with your doctor and weigh the benefits against the potential risks. You should not breastfeed if you have HIV or AIDS, however, as the infection may be passed onto the baby through the breastmilk.

Your doctor will need to check on your progress regularly during use of this treatment. Tests may need to be carried out to look for unwanted side effects as well as to check for progress.

This medication can cause sores to develop on the genitals. Washing genitals after sexual intercourse and urination can help to decrease the risk of developing this problem.

You should have your eyes checked by an ophthalmologist when you are using this treatment. You may lose some eyesight during the use of this treatment and this needs to be monitored and managed.

You may become dizzy or less focused following use of this treatment. It may also affect eyesight. You should not drive, operate machinery or do anything that may put you or others at risk unless you are safe to operate. Remember that it is your legal responsibility to ensure this at all times.

You should not take any other medications with this treatment unless you have discussed this use with your doctor.


This medication should not be stored at temperatures above 40°C. It should be kept at room temperature.

Diluted solutions can be used for treatment for 24 hours only. After this period the medication should be disposed of.


Foscarnet is an injected treatment that is used for the treatment of serious viral infections in patients who have a compromised immune system. This commonly occurs in patients suffering from AIDS and the most commonly treated condition with Foscarnet is cytomegalovirus (CMV) in patients with AIDS. It is also commonly used in the treatment of herpes simplex virus (HSV) in patients who are suffering from an immunocompromised condition.

Foscarnet is administered directly into the veins through infusion. It is administered over 1-3 hours and needs to be administered every 8 hours to the patient for a period of 2-3 weeks.

Foscarnet can interact with a wide range of other medications and you should be certain to inform your doctor of all other treatments that you are taking before beginning use.

This medication can make you dizzy and less alert. It should not be used in conjunction with driving or the operation of heavy machinery.