HPMPC
HPMPC - General Information
HPMPC is an injectable antiviral medication for the treatment of cytomegalovirus (CMV) retinitis in patients with AIDS. It suppresses CMV replication by selective inhibition of viral DNA synthesis. [Wikipedia]
Pharmacology of HPMPC
HPMPC is a new anti-viral drug. It is classified as a nucleotide analogue and is active against herpes cytomegalovirus (CMV) retinitis infection. Most adults are infected with CMV. HPMPC suppresses cytomegalovirus (CMV) replication by selective inhibition of viral DNA synthesis. Biochemical data support selective inhibition of CMV DNA polymerase by cidofovir diphosphate, the active intracellular metabolite of cidofovir. HPMPC diphosphate inhibits herpesvirus polymerases at concentrations that are 8- to 600-fold lower than those needed to inhibit human cellular DNA polymerase alpha, beta, and gamma(1,2,3). Incorporation of cidofovir into the growing viral DNA chain results in reductions in the rate of viral DNA synthesis.
HPMPC for patients
CIDOFOVIR
Other names: Vistide®
WHY is this medication prescribed ?
Cidofovir is an antiviral medication used for the treatment of Cytomegalovirus (CMV) infection. The drug is also used to prevent a relapse of CMV after the initial treatment of the infection.
HOW should this drug be taken ?
Cidofovir is given intravenously every week for two weeks and then on alternating weeks for an indefinite period of time. The protocol for cidofovir administration is as follows: · 2000 mg oral dose of probenecid (4 x 500 mg tablets) three hours prior to cidofovir
1 liter infusion of saline one hour prior to cidofovir
Cidofovir infusion over one hour.
While cidofovir is infusing, another liter of saline may be given over 1 to 3 hours.
1000 mg (2 x 500 mg tablets) of probenecid 2 hours after the cidofovir infusion is completed
1000 mg (2 x 500 mg tablets) of probenicid 8 hours after the cidofovir infusion is completed.
What ADVERSE EFFECTS can this drug cause? What should you do about them?
The most serious and commonly reported negative effect of intravenous cidofovir is kidney toxicity. Your kidney status will be checked the day before you receive an infusion of cidofovir. If measurements of serum creatinine and protein in your urine are not within acceptable limits, your physician will either reduce your dose or discontinue therapy. Hydration with normal saline and administration of oral probenecid help to reduce the risk of kidney toxicity.
Cidofovir can also cause a fall in the number of white blood cells. This can increase your risk of developing infections as white blood cells are needed to fight infections. Cidofovir can also decrease platelets. This can increase your risk of bleeding or bruising as platelets are need to help your blood clot. Your red blood cells may also decrease which could make you feel tired or short of breath. Blood tests will be done regularly to check for any changes in these values. If there are any serious problems, cidofovir will be stopped. Nausea, fever, hair loss and muscle pain can also occur as a result of cidofovir therapy. If these effects persist and are bothersome, please call the clinic or discuss this at your next visit.
Some side effects experienced by patients treated with cidofovir may be related to probenecid. These side effects are rash, nausea, vomiting and fever. Eating food before taking probenecid helps reduce the risk of nausea and vomiting. Patients who experience rash or itching are usually given an antihistamine to reduce symptoms. Inform you doctor if you experience intolerable side effects.
IF YOU ARE EXPERIENCING ANY ADVERSE EFFECTS PLEASE DISCUSS THEM WITH YOUR HEALTH CARE TEAM.
IT IS IMPORTANT THAT YOU KEEP YOUR REGULAR DOCTOR'S APPOINTMENTS, SO THAT YOUR PROGRESS CAN BE ASSESSED.
What other PRECAUTIONS should you follow while using this drug?
If while handling the drug, it accidentally spills, avoid contact with your skin, eyes, or mucous membranes (eg. nose). Wear rubber gloves while cleaning up any spills. If the drug comes in contact with your skin or mucous membranes, wash the area thoroughly with soap and water, and rinse thoroughly with water.
Once started on cidofovir therapy, it is to be continued indefinitely even if you begin to feel your vision is improving. Maintain you regular visits and inform your doctor of any new medical problems that develop while you are receiving cidofovir.
Birth defects have occurred in animals exposed to cidofovir, therefore cidofovir should be used during pregnancy only if the potential justifies the risk to the fetus. It is not known if cidofovir is excreted into breast milk. Because of abnormalities which have occurred in animals treated with cidofovir, it is possible that nursing infants may also be affected, therefore cidofovir should not be given to breast feeding mothers. If these issues are a concern to you, please discuss this with your doctor or pharmacist.
Other medications may affect the way cidofovir works and so increase the chance of side effects. Also probenecid may affect the way other agents work. For example, if you are taking zidovudine (AZT), you should decrease you daily dose by 50% on the day you receive probenecid/cidofovir. Inform your doctor and pharmacist about all of the medications you are taking, and do not start taking other medications without discussing this first.
HPMPC Interactions
Probenecid : Probenecid is known to interact with the metabolism or renal tubular excretion of many drugs (e.g., acetaminophen, acyclovir, angiotensin-converting enzyme inhibitors, aminosalicylic acid, barbiturates, benzodiazepines, bumetanide, clofibrate, methotrexate, famotidine, furosemide, nonsteroidal anti-inflammatory agents, theophylline, and zidovudine). Concomitant medications should be carefully assessed. Zidovudine should either be temporarily discontinued or decreased by 50% when coadministered with probenecid on the day of VISTIDE infusion.
Nephrotoxic agents : Concomitant administration of VISTIDE and agents with nephrotoxic potential [e.g., intravenous aminoglycosides (e.g., tobramycin, gentamicin, and amikacin), amphotericin B, foscarnet, intravenous pentamidine, vancomycin, and non-steroidal anti-inflammatory agents] is contraindicated. Such agents must be discontinued at least seven days prior to starting therapy with VISTIDE.
HPMPC Contraindications
Initiation of therapy with VISTIDE is contraindicated in patients with a serum creatinine > 1.5 mg/dL, a calculated creatinine clearance ≤ 55 mL/min, or a urine protein ≥ 100 mg/dL (equivalent to ≥ 2 + proteinuria).
VISTIDE is contraindicated in patients receiving agents with nephrotoxic potential. Such agents must be discontinued at least seven days prior to starting therapy with VISTIDE.
VISTIDE is contraindicated in patients with hypersensitivity to cidofovir.
VISTIDE is contraindicated in patients with a history of clinically severe hypersensitivity to probenecid or other sulfa-containing medications.
Direct intraocular injection of VISTIDE is contraindicated; direct injection of cidofovir has been associated with iritis, ocular hypotony, and permanent impairment of vision.
Additional information about HPMPC
HPMPC Indication: For the treatment of CMV retinitis in patients with acquired immunodeficiency syndrome (AIDS)
Mechanism Of Action: HPMPC acts through the selective inhibition of viral DNA polymerase.
Drug Interactions: Not Available
Food Interactions: Not Available
Generic Name: Cidofovir
Synonyms: CDV; Cidofovir Anhydrous
Drug Category: Anti-HIV Agents; Radiation-Sensitizing Agents; Antineoplastic Agents; Antiviral Agents
Drug Type: Small Molecule; Approved
Other Brand Names containing Cidofovir: HPMPC; Vistide;
Absorption: 100%
Toxicity (Overdose): Kidney damage, fall in the number of white blood cells, decreased platelets
Protein Binding: 6%
Biotransformation: Not Available
Half Life: 2.4 to 3.2 hours
Dosage Forms of HPMPC: Solution Intravenous
Chemical IUPAC Name: [(2S)-1-(4-amino-2-oxopyrimidin-1-yl)-3-hydroxypropan-2-yl]oxymethylphosphonic acid
Chemical Formula: C8H14N3O6P
Cidofovir on Wikipedia: https://en.wikipedia.org/wiki/Cidofovir
Organisms Affected: Human Immunodeficiency Virus
