Praziquantel
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Praziquantel
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| Systematic (IUPAC) name | |
| 2-(Cyclohexylcarbonyl) -1,2,3,6,7,11b-hexahydro-4H-pyrazino (2,1-alpha) isoquinolin-4-one | |
| Identifiers | |
| CAS number | 55268-74-1 |
| ATC code | P02BA01 |
| PubChem | 4891 |
| DrugBank | EXPT02728 |
| Chemical data | |
| Formula | C19H24N2O2 |
| Mol. weight | 312.411 |
| Pharmacokinetic data | |
| Bioavailability | relatively small |
| Metabolism | hepatic |
| Half life | 0.8 to 1.5 hours (Main Metabolites 4 to 5 hours) |
| Excretion | mainly in urine |
| Therapeutic considerations | |
| Pregnancy cat. |
Only when clearly needed (lack of sufficient data in humans) |
| Legal status |
Rx-only, designed as indispensable drug by WHO |
| Routes | oral |
Contents |
[edit] History
Praziquantel was developed in the laboratories for parasitological research of Bayer AG in Germany (Elberfeld) 30 years ago (in the mid 1970's). Since then it has proven indispensable in more and more indications and is recognized as such by the World Health Organization.
[edit] Pharmacokinetics
Praziquantel is well (approximately 80%) absorbed from the GI Tract. Due to extensive first pass metabolization only relatively small amounts enter systemic circulation. Praziquantel has a serum halflife of 0.8 to 1.5 hours (metabolites 4 to 5 hours) in adults with normal renal and liver function. In patients with significantly impaired liver function (Child Pugh classes B and C) the serum halflife is increased to 3 to 8 hours. Praziquantel and its metabolites are mainly excreted in the urine, within 24 hours after a single oral dose 70 to 80% are recovered in urine, but less than 0.1% are found as the unchanged drug.
[edit] Mode of Action
Although the mode of action is not exactly known at present, there is experimental evidence that Praziquantel increases the permeability of the membranes of parasite cells (certain schistosomes) for calcium ions. The drug thereby induces contraction of the parasites resulting in paralysis in the contracted state. The dying parasites are dislodged from their site of action in the host organism and may enter systemic circulation or may be destroyed by host immune reaction (phagocytosis). Additional mechanisms - focal disintegrations and disturbances of oviposition (laying of eggs) - are seen in other types of sensitive parasites.
[edit] Uses
Praziquantel (Biltricide) is an antiparasitic (antihelmintic) medication primarily used for the treatment of schistosomiasis (Snail Fever) and fascioliasis (Liver Flukes). It is also used to treat echinococcosis, cysticercosis and intestinal tapeworms. As of 2005 praziquantel is the primary treatment for human schistosomiasis, for which it is usually effective in a single dose. It is also marketed as a veterinary medicine.
Praziquantel is not licensed for use in humans in the UK; it is however available as a veterinary antibiotic, and is available for use in humans on a named-patient basis.
Praziquantel is an "antihelmintic," or anti-worm, medication. It prevents worms from growing or multiplying in your body.
Praziquantel is used to treat infections caused by worms in the Schistosoma family of worms.
Praziquantel may also be used for purposes other than those listed in this medication guide.
[edit] Contraindications and Precautions
- Hypersensitivity to Praziquantel (absolute contraindication)
- Intraocular Cysticercosis (absolute contraindication, treatment may cause blindness)
- Cerebral Cysticercosis (hospitalization recommended)
- Patients with cardiac arrhythmias (monitoring required)
- Hepatosplenic patients with schistosomias and intercurrent moderate to severe liver impairment (Child Pugh classes B and C)
[edit] Side effects
The majority of side-effects develop due to the killing of parasites, release of contents of parasites and consequent host immune reactions. The heavier the parasite burden, the heavier and more frequent the side effects normally are.
- Central Nervous System : Frequent are dizziness, headache and malaise. Drowsiness, somnolence, fatigue and vertigo have also been seen. Almost all patients with cerebral cysticercosis experience CNS side effects related to the cell-death of the parasites (headache, worsening of preexisting neurological problems, seizures, arachnoiditis, and meningism). These side effects may be life-threatening and can be reduced by coadministration of corticoids. It is strongly recommended that all patients with cerebral cysticercosis are hospitalized during treatment.
- GI Tract : Approximately 90% of all patients have abdominal pain or cramps with or without nausea and vomiting. Diarrhea may develop and may be severe with colicky. Sweating, fever, and sometimes bloody stools may emerge together with diarrhea.
- Liver : Asymptomatic and transient increases of liver enzymes (AST and ALT) are noted frequently (up to 27%). No case of symptomatic liver damage has ever been seen so far.
- Sensitivity Reactions : Urticaria, rash, pruritus and eosinophilia in White Blood Counts.
- Other Locations/Body as a Whole : Low Back Pain, myalgia, arthralgia, fever, sweating, various cardiac arrhythmias, and hypotension.
[edit] Dosage
According to special dosing schedules for each different indication. Sometimes one single dose or a one-day treatment with divided doses may be sufficient.
[edit] Brand names
- Biltricide® (Bayer) 600mg Tablets
- Cesol® Tablets
- Cysticide® Tablets
- Profender® (Bayer) for veterinary use
- Droncit® (Bayer) for veterinary use
- D-Worm™ (Farnum) for veterinary use
- Tape Worm Tabs™ (Trade Winds) for veterinary use
- PraziPro™ (Hikari®) for aquarium use
[edit] External references
- AHFS Database
