Albenza (Albendazole) 400mg

Albendazole

Albendazole is a synthetic, benzimidazole-derivative anthelmintic agent. The drug is structurally related to thiabendazole and mebendazole, and like mebendazole, it is a benzimidazole carbamate derivative. Albendazole is metabolized in the liver to an active metabolite, albendazole sulfoxide, which accounts for detectable plasma concentrations of the drug; systemic anthelmintic activity of the drug has been attributed to this metabolite.

Although the exact mechanism of action of albendazole has not been fully elucidated, the principal anthelmintic effect of benzimidazoles, including albendazole, appears to be the specific, high-affinity binding of the drug to free tubulin in parasite cells, resulting in selective inhibition of parasite microtubule polymerization, and inhibition of microtubule-dependent uptake of glucose. Benzimidazole drugs bind to the tubulin of parasites at much lower concentrations than to mammalian tubulin protein; the drugs do not inhibit glucose uptake in mammals, and do not appear to have any effect on blood glucose concentrations in humans. SumMon® (see Users Guide).

For additional information on this drug until a more detailed monograph is developed and published, the manufacturer’s labeling should be consulted. It is essential that the labeling be consulted for detailed information on the usual cautions, precautions, and contraindications.

Uses

Cestode (Tapeworm) Infections

Albendazole is used in the treatment of tissue infections caused by the larval forms of certain cestodes (tapeworms) including neurocysticercosis caused by Cysticercus cellulosae, the larval form of Taenia solium (pork tapeworm). Albendazole also is used for the treatment of hydatid disease caused by the larval form of Echinococcus granulosus (dog tapeworm). Other anthelmintics (usually praziquantel) are used for the treatment of intestinal infections caused by adult forms of cestodes.

Neurocysticercosis

Albendazole is used for the treatment of parenchymal neurocysticercosis resulting from active lesions caused by Cysticercus cellulosae, the larval form of Taenia solium (pork tapeworm), preferably in combination with corticosteroids. Symptoms commonly associated with neurocysticercosis include headaches, seizures, or other CNS effects thought to result from expanding active cysticercal lesions or edema surrounding individual degenerating cysts in brain parenchyma. Therefore, important measures of response to antineurocysticercal therapy include resolution of CNS symptoms and radiologic response.

The manufacturer states that safety and efficacy of albendazole in patients with neurocysticercosis caused by T. solium was demonstrated by analysis of 3 sets of data, including a compilation of data from published reports of albendazole use in neurocysticercosis, data from US compassionate use patients, and data from one limited clinical study. In studies of patients with susceptible neurocysticercal lesions (i.e., nonenhancing cysts with no surrounding edema on contrast-enhanced computerized tomography) receiving albendazole, the number of cysts was reduced by 74-88%, and resolution of all active cysts occurred in 40-70% of patients.

Combining two of the data sets (the report compilation and the US compassionate use data), the manufacturer states that about 41% of patients experienced a cure (no symptoms of neurocysticercosis), about 50% of patients were considered to be improved, and 9% experienced no change. Corticosteroids are used concomitantly to reduce the frequency and severity of adverse nervous system effects (CSF reaction syndrome), associated with albendazole therapy for neurocysticercosis. Anticonvulsant therapy also may be necessary. Use of anthelmintics (albendazole or praziquantel) in the treatment of cysticercosis is controversial since efficacy has not been proven in controlled studies. Initial treatment of parenchymal disease with seizures should focus on symptomatic treatment with anticonvulsants.

Obstructive hydrocephalus is treated with surgical removal of the obstructing cyst or CSF diversion and prednisone; arachnoiditis, vasculitis, or cerebral edema is treated with corticosteroids (prednisone or dexamethasone) used in conjunction with albendazole or praziquantel. Even when corticosteroids are used, any cysticercocidal drug may cause irreparable damage when used to treat ocular or spinal cysts, and ophthalmic exams should be performed before treatment to rule out intraocular cysts.

Hydatid Disease

Albendazole is used for the treatment of cystic hydatid disease (unilocular hydatid disease) of the liver, lung, and peritoneum, caused by the larval form of the dog tapeworm (Echinococcus granulosus). Surgery is considered to be the treatment of choice for hydatid disease, when medically feasible, but perioperative administration of an anthelmintic drug (e.g., albendazole, mebendazole, praziquantel) may be indicated in patients undergoing surgical removal of cysts to minimize the risk of intraoperative dissemination of daughter cysts. Percutaneous drainage with ultrasound guidance plus albendazole therapy has been effective for the management of hepatic hydatid cyst disease.

Albendazole is absorbed to a greater extent, and achieves higher plasma concentrations (as its active metabolite) than mebendazole, and some clinicians consider albendazole to be a drug of choice for treatment of hydatid cyst disease caused by E. granulosus. Risks associated with surgery include operative morbidity, cyst recurrence, and anaphylaxis or dissemination of infection resulting from spillage of fluid from the cysts.

Preoperative administration of albendazole may inactivate protoscolices and minimize the possibility of recurring cysts, and postoperative treatment with the drug may prevent secondary dissemination of the cestode that can occur after spontaneous or operative rupture and spillage of cyst contents. Optimal cysticidal effect of albendazole is achieved preoperatively or postoperatively when the drug is administered in three 28-day courses of therapy.

Also, some clinicians have recommended administration of albendazole in patients with inoperable, widespread, or numerous E. granulosus cysts, or in patients with complex medical problems who are not eligible for surgery. The manufacturer states that because of the low incidence of hydatid disease, safety and efficacy of albendazole in patients with hydatid disease caused by E. granulosus was demonstrated by combining data from accumulated clinical reports in small series of patients.

Four sets of data were considered, including data from European compassionate use patients, an analysis of data from published studies, data from Australian compassionate use patients (not evaluable), and data from US compassionate use patients. About 80-90% of patients receiving albendazole in three 28-day cycles had noninfectious cyst contents. About 30-31% of evaluable patients with hydatid disease receiving albendazole experienced a clinical cure (i.e., disappearance of cysts), and improvement (i.e., a reduction in cyst diameter of at least 25%) was observed in about 40-42% of evaluable patients. About 24% of patients receiving albendazole experienced no change or were considered to be worse.

Although albendazole has been used to treat alveolar hydatid disease, another form of hydatid cyst disease caused by Echinococcus multilocularis, surgical excision of the larval mass is the recommended and only reliable treatment for this infection. Continuous albendazole or mebendazole therapy reportedly has been associated with clinical improvement in nonresectable cases, but the manufacturer states that efficacy of albendazole in the treatment of alveolar hydatid disease caused by E. multilocularis has not been demonstrated in clinical studies.

Nematode (Roundworm) Infections

Ascariasis

Albendazole is used for the treatment of ascariasis caused by Ascaris lumbricoides. Albendazole, mebendazole, or pyrantel pamoate are considered the drugs of choice for the treatment of ascariasis.

Enterobiasis

Albendazole is used for the treatment of enterobiasis caused by Enterobius vermicularis (pinworm). Albendazole, mebendazole, or pyrantel pamoate are considered the drugs of choice for the treatment of enterobiasis.

Filariasis

Albendazole or mebendazole are recommended as the drugs of choice for the treatment of filariasis caused by Mansonella perstans. Diethylcarbamazine (available in the US from the US Centers for Diseases Control and Prevention [CDC]) or ivermectin usually are recommended for the treatment of infections caused by most other filarial worms.

Hookworm Infections

Albendazole is used for the treatment of intestinal hookworm infections caused by Ancylostoma duodenale or Necator americanus, and albendazole, mebendazole, or pyrantel pamoate are considered the drugs of choice for intestinal hookworm infections. Albendazole is used for the treatment of cutaneous larva migrans (creeping eruption) caused by dog and cat hookworms. Although cutaneous larva migrans usually is self-limited with spontaneous cure after several weeks or months, albendazole, ivermectin, or thiabendazole are considered the drugs of choice when treatment is indicated. Albendazole, mebendazole, or pyrantel pamoate are considered drugs of choice for the treatment of eosinophilic enterocolitis caused by Ancylostoma caninum (dog hookworm).

Toxocariasis (Visceral Larva Migrans)

Albendazole is used for the treatment of toxocariasis (visceral larva migrans) caused by Toxocara canis or T. cati (dog and cat roundworms), and albendazole or mebendazole are considered the drugs of choice for these infections. In severe cases with cardiac, ocular, or CNS involvement, corticosteroids also may be indicated. Treatment may not be effective in ocular larva migrans; inflammation may be reduced by corticosteroid injections and surgery may be necessary for secondary damage.

Trichinosis

Albendazole is used for the treatment of trichinosis caused by Trichinella spiralis. Although some clinicians state that albendazole and mebendazole are equally effective for the treatment of trichinosis, other clinicians consider mebendazole the drug of choice and albendazole the alternative agent. Use of corticosteroids in addition to the anthelmintic usually is recommended, especially when symptoms are severe. Corticosteroids alleviate symptoms of the inflammatory reaction and can be lifesaving when cardiac or CNS systems are involved.

Baylisascariasis

Albendazole has been used in a limited number of patients for the treatment of baylisascariasis caused by Baylisascaris procyonis; however, no drug has been demonstrated to be effective for the treatment of this infection. B. procyonis, a common roundworm found in the small intestine of raccoons, can cause severe or fatal encephalitis (neural larva migrans) in birds and mammals (including humans) and also can cause ocular and visceral larva migrans in humans. Since 1981, there have been at least 12 cases of severe or fatal encephalitis caused by this roundworm in the US (CA, IL, MI, MN, NY, OR, PA) and 10 of these cases occurred in children 9 months to 6 years of age; cases of B. procyonis ocular larva migrans also have been reported in the US. Humans become infected by ingesting B. procyonis eggs after contact with infected raccoon feces.

Because CNS damage can occur before symptom onset, treatment of symptomatic patients with anthelmintic or anti-inflammatory agents often will not improve outcome. However, the CDC states that use of an anthelmintic agent (i.e., albendazole 25-50 mg/kg daily for 10 days) started within 1-3 days of possible infection might prevent clinical disease by killing larvae before they enter the CNS.

Therefore, immediate treatment is recommended in cases of probable infection, including known exposures such as ingestion of raccoon stool or contaminated soil. Corticosteroid therapy also may be helpful, especially in ocular and CNS infections; ocular baylisascariasis has been treated successfully using laser photcoagulation therapy to destroy the intraretinal larvae. Additional information on baylisascariasis can be obtained at http://www.cdc.gov/ncidod/dpd/parasites/baylisacaris/default.htm.

Other Nematode Infections

Albendazole has been used in the treatment of capillariasis caused by Capillaria philippinensis. Mebendazole is considered the drug of choice for the treatment of capillariasis, and albendazole is considered an alternative. For the treatment of gnathostomiasis caused by Gnathostoma spinigerum, use of albendazole, ivermectin, or surgical removal is recommended. For the treatment of gongylonemiasis caused by Gongylonema, surgical removal or use of albendazole is recommended.

Albendazole is used in the treatment of infections caused by Trichostrongylus. Pyrantel pamoate is considered the drug of choice and albendazole or mebendazole are alternatives for the treatment of Trichostrongylus infections. Albendazole is used as an alternative to mebendazole for the treatment of trichuriasis caused by Trichuris trichiura (whipworm). Albendazole or pyrantel pamoate may be effective for the treatment of oesophagostomiasis caused by Oesophagostomum bifurcum.

Trematode (Fluke) Infections

For the treatment of infections caused by Clonorchis sinensis (Chinese liver fluke), albendazole or praziquantel are recommended as the drugs of choice. Other anthelmintics (usually praziquantel) are recommended for all other fluke infections.

Giardiasis

Although metronidazole generally is the drug of choice for the treatment of giardiasis caused by Giardia lamblia, albendazole may be effective for the treatment of giardiasis. Albendazole may be as effective as metronidazole for treating giardiasis in pediatric patients and has fewer adverse effects.

Microsporidiosis

Albendazole has been used in the treatment of microsporidiosis. Microsporidia can cause ocular infections (Encephalitozoon hellem, E. cuniculi, Vittaforma corneae), intestinal infections (Enterocytozoon bieneusi, Encephalitozoon intestinalis), and disseminated infections (E. hellem, E. cuniculi, E. intestinalis, Pleistophora, Trachipleistophora, Brachiola vesicularum). Intestinal infections are most common in immunocompromised patients, and are being reported with increasing frequency in patients with human immunodeficiency virus (HIV) infection.

Some clinicians recommend use of albendazole in conjunction with fumagillin (not commercially available in the US) for the treatment of ocular microsporidiosis and also consider albendazole the drug of choice for intestinal infections caused by E. intestinalis and for disseminated microsporidiosis. Although some patients with intestinal microsporidiosis caused by E. intestinalis may respond to albendazole, the organism is not eradicated in all patients and recurrence of diarrhea is common after therapy is stopped. Patients with E. bieneusiinfections generally do not respond to albendazole.

Dosage and Administration

Administration

Albendazole is administered orally with food. Oral bioavailability of albendazole appears to be increased when the drug is administered with a fatty meal; when the drug is administered with meals containing about 40 g of fat, plasma concentrations of albendazole sulfoxide are up to 5 times higher than those observed when the drug is administered to fasting patients.

Albendazole may cause harm to the fetus and should be used during pregnancy only if the benefits justify the risk to the fetus and only in clinical circumstances where no alternative management is appropriate. Women of childbearing age should begin treatment only after a negative pregnancy test, and should be cautioned against becoming pregnant while receiving albendazole or within 1 month of completing treatment with the drug.

Because albendazole has been associated with mild to moderate increases of hepatic enzymes in about 16% of patients receiving the drug in clinical trials, and may cause hepatotoxicity, liver function tests should be performed prior to each course of albendazole therapy and at least every 2 weeks during treatment with the drug. If clinically important increases in liver function test results occur, albendazole should be discontinued. Leukopenia has occurred in less than 1% of patients receiving albendazole, and rarely, granulocytopenia, pancytopenia, agranulocytosis, or thrombocytopenia have been reported.

Therefore, blood counts should be performed at the start of, and every 2 weeks during, each 28-day treatment cycle. The manufacturer states that if decreases in the total leukocyte count occur, treatment with albendazole may be continued if the decreases are modest and do not progress.

Dosage

Cestode (Tapeworm) Infections Neurocysticercosis

Because of its activity against the pork tapeworm (T. solium), albendazole therapy for the treatment of neurocysticercosis resulting from active lesions caused by Cysticercus cellulosae (the larval form of T. solium) has been associated with adverse CNS effects (e.g., seizures and/or hydrocephalus) resulting from inflammatory reactions to damaged intracerebral cysts. Therefore, patients receiving albendazole for the treatment of neurocysticercosis should receive appropriate corticosteroid and anticonvulsant therapy as required. Oral or IV corticosteroid therapy should be considered during the first week of albendazole treatment to prevent cerebral hypertension.

Although retinal cysticercosis is rare, patients with neurocysticercosis may have retinal lesions, and destruction of cysticercal lesions by albendazole may cause retinal damage. Therefore, patients should be examined for retinal lesions, and, if any are present, the need for treatment of patients with neurocysticercosis should be weighed against the possibility of retinal damage resulting from albendazole use.

For the treatment of neurocysticercosis in adults and children 6 years of age and older and weighing 60 kg or more, the usual dosage of albendazole is 400 mg given twice daily with meals for 8-30 days. For the treatment of neurocysticercosis in patients weighing less than 60 kg, the usual daily dosage of albendazole is 15 mg/kg daily (not to exceed 800 mg daily), administered as 2 equally divided doses with meals, for 8-30 days. Courses of therapy may be repeated as necessary.

Hydatid Disease

Surgery is considered the treatment of choice for hydatid disease, when medically feasible, and albendazole is administered either before or after surgery. When albendazole is used for the adjunctive perioperative treatment of hydatid disease, optimal killing of cyst contents is achieved by administering the drug in three 28-day courses of therapy, separated by two 14-day albendazole-free intervals. For the treatment of cystic hydatid disease of the liver, lung, or peritoneum caused by the larval form of the dog tapeworm (Echinococcus granulosus) in adults or children 6 years of age and older and weighing 60 kg or more, the usual dosage of albendazole is 400 mg twice daily given with meals for 28 days, followed by a 14-day albendazole-free interval for a total of 3 dosage cycles. For patients weighing less than 60 kg, the usual dosage is 15 mg/kg daily (not to exceed 800 mg daily), administered in 2 equally divided doses with meals for 28 days, followed by a 14-day albendazole-free interval for a total of 3 dosage cycles. Some clinicians recommend that adults receive 400 mg of albendazole twice daily and that pediatric patients receive 15 mg/kg daily (not to exceed 800 mg daily) for 1-6 months for the treatment of hydatid cyst disease.

Nematode (Roundworm) Infections Ascariasis

For the treatment of ascariasis caused by Ascaris lumbricoides, adult and pediatric patients should receive a single 400-mg dose of albendazole. Enterobiasis For the treatment of enterobiasis caused by Enterobius vermicularis (pinworm), some clinicians recommend that adult and pediatric patients receive an initial 400-mg dose of albendazole and a second 400-mg dose given 2 weeks later.

Filariasis

For the treatment of filariasis caused by Mansonella perstans, some clinicians recommend that adults and pediatric patients receive albendazole in a dosage of 400 mg twice daily for 10 days.

Hookworm Infections

For the treatment of intestinal hookworm infections caused by Ancylostoma duodenale or Necator americanus or for eosinophilic enterocolitis caused by Ancylostoma caninum (dog hookworm), some clinicians recommend that adult and pediatric patients receive a single 400-mg dose of albendazole. For the treatment of cutaneous larva migrans (creeping eruption) caused by dog or cat hookworms, some clinicians recommend that adults and pediatric patients receive albendazole in a dosage of 400 mg once daily for 3 days.

Toxocariasis (Visceral Larva Migrans)

For the treatment of treatment of toxocariasis (visceral larva migrans) caused by dog and cat roundworms, some clinicians recommend that adults and pediatric patients receive albendazole in a dosage of 400 mg twice daily for 5 days. However, optimum duration of therapy is not known and some clinicians recommend that treatment be continued for up to 20 days.

Trichinosis

The recommended dosage of albendazole for the treatment of trichinosis caused by Trichinella spiralis in adults and pediatric patients is 400 mg twice daily for 8-14 days. Baylisascariasis In an attempt to prevent clinical disease by killing larvae before they enter the CNS, the US Centers for Disease Control and Prevention (CDC) recommends early (with 1-3 days of possible infection) albendazole therapy at a dosage of 25-50 mg/kg daily for 10 days. Immediate treatment is recommended if infection is probable; treatment should not be delayed until the emergence of symptoms. 18 (See Cestode [Tapeworm] Infections: Baylisascariasis, in Uses.)

Other Nematode Infections

For the treatment of capillariasis caused by Capillaria philippinensis, some clinicians recommend that adults and pediatric patients receive albendazole in a dosage of 400 mg once daily for 10 days. Adults and pediatric patients with gnathostomiasis caused by Gnathostoma spinigerum should receive albendazole in a dosage of 400 mg twice daily for 21 days and adults and pediatric patients with gongylonemiasis caused by Gongylonema should receive the drug in a dosage of 10 mg/kg daily given for 3 days.

For the treatment of infections caused by Trichostrongylus, adults and pediatric patients should receive a single 400-mg dose of albendazole. Adults and pediatric patients with trichuriasis caused by Trichuris trichiura (whipworm) should receive albendazole in a dosage of 400 mg once daily for 3 days. Trematode (Fluke) Infections For the treatment of infections caused by Clonorchis sinensis (Chinese liver fluke), some clinicians recommend that adults and pediatric patients receive albendazole in a dosage of 10 mg/kg daily given for 7 days.

Giardiasis

For the treatment of giardiasis caused by Giardia lamblia in adults and pediatric patients, albendazole has been given in a dosage of 400 mg daily for 5 days. Microsporidiosis For the treatment of ocular or disseminated microsporidiosis, some clinicians recommend that adults receive albendazole in a dosage of 400 mg twice daily. For the treatment of intestinal microsporidiosis caused by Encephalitozoon intestinalis, some clinicians recommend that adults receive albendazole in a dosage of 400 mg twice daily for 21 days.

Preparations

Albendazole

Oral Tablets, film- 200 mg Albenza® Tiltab®, (with coated povidone) GlaxoSmithKline

Albendazole Side Effects

Albendazole, a benzimidazole derivative closely related to mebendazole (qv), is used in the treatment of helminth infections, such as gastrointestinal roundworms, hydatid disease, neurocysticercosis, larva migrans cutanea, and strongyloidiasis. Provided that an adequate concentration is attained within the cyst, it is scolicidal. In high doses given for prolonged periods or cyclically, it is effective in echinococcosis, in which it is given in a dosage of 10 mg/kg/day for 4 weeks, repeated in six cycles with 2-week rest periods between each cycle, although even with this high dose only about one-third of patients enjoy a complete cure, some 70% having a partial response. Albendazole is also active against Pneumocystis jiroveci, and is effective in prophylaxis and treatment in immunosuppressed mice. In hydatid disease a combination of albendazole and praziquantel is effective when either agent has failed when used alone.

Albendazole: Observational and Comparative studies

Placebo-controlled studies

Albendazole has been used in the treatment and prophylaxis of microsporidiosis in patients with AIDS. In a small, double-blind, placebo-controlled trial from France the efficacy and safety of treatment with albendazole was studied in four patients treated with albendazole 400 mg bd for 3 weeks and in four patients treated with placebo. Microsporidia were cleared in all patients given albendazole but in none of those given placebo. Afterwards all eight patients were again randomized to receive either maintenance treatment with albendazole 400 mg bd or no treatment for the next 12 months; none of the three patients taking maintenance treatment had a recurrence, while three of the five who took no maintenance therapy developed a recurrence. During the double-blind part of the trial there were no serious adverse effects in the patients who took albendazole, although two complained of headache, one of abdominal pain, one had raised transaminase activities, and one had thrombocytopenia. However, half the patients were also taking anti-HIV triple therapy, which makes it difficult to assess these abnormalities. The authors concluded that the adverse effects were not serious and did not hinder maintenance therapy. The tentative conclusion derived from these findings is that albendazole may be useful in the treatment of microsporidiosis, which in patients with AIDS often leads to debilitating chronic diarrhea and is difficult to treat.

Use in non-infective conditions

The efficacy of albendazole has been evaluated in a few patients with either hepatocellular carcinoma or colorectal cancer and hepatic metastases refractory to other forms of treatment. Apart from hematological and biochemical indices, the tumor markers car-cinoembryonic antigen (CEA) and alpha-fetoprotein (AFP) were measured to monitor treatment efficacy. One other patient with a neuroendocrine cancer and a mesothelioma was treated on a compassionate basis and only monitored for adverse effects. Albendazole was given orally in a dose of 10 mg/kg/day in two divided doses for 28 days. Albendazole reduced CEA in two patients and in the other five patients with measurable tumor markers, serum CEA or AFP was stabilized in three. In the seven patients who completed this pilot study, albendazole was well tolerated and there were no significant changes in any hematological, kidney, or liver function tests. However, three patients were withdrawn because of severe neutropenia, which resulted in the death of one. Neutropenia was more frequent than is usually experienced in the treatment of hydatid disease. The authors speculated that this may relate to reduced metabolism in patients with liver cancer or liver metastases, leading to the passage of unmetabolized drug into the circulation.

General adverse effects

As with other antihelminthic drugs, the general adverse effects of albendazole can reflect the destruction of the parasite rather than a direct action of the drug; pyrexia is likely to be seen, even in the absence of other problems. Albendazole was well tolerated in 30-day courses of 10-14 mg/kg/day separated by 2-week intervals.

Its adverse effects are similar to those of mebendazole and are possibly more common because of better and more reliable absorption.

The direct adverse effects of albendazole are few and usually minor, and consist of gastrointestinal upsets, dizziness, rash, and alopecia, which usually do not require drug withdrawal. Early pyrexia and neutropenia can also occur. Cyst rupture can also occur, as with mebendazole. About 15% of patients treated with albendazole at higher doses develop raised serum trans-aminases, necessitating careful monitoring and sometimes withdrawal of treatment after prolonged use. Careful monitoring of leukocyte and platelet counts is also indicated. The possibility of teratogenicity and embryotoxicity from animal studies suggests that the drug should be avoided in pregnancy.

Second-Generation Effects Teratogenicity

It has been emphasized that albendazole is teratogenic in animals and should not be used in pregnancy.

Drug-Drug Interactions

Antiepileptic drugs

The pharmacological interactions of the antiepileptic drugs phenytoin, carbamazepine, and phenobarbital with albendazole have been studied in 32 adults with active intraparenchymatous neurocysticercosis:

• nine patients took phenytoin 3-4 mg/kg/day;
• nine patients took carbamazepine 10-20 mg/kg/day;
• five patients took phenobarbital 1.5-4.5 mg/kg/day;
• nine patients took no antiepileptic drugs.

All were treated with albendazole 7.5 mg/kg every 12 hours on 8 consecutive days. Phenytoin, carbamazepine, and phenobarbital all induced the oxidative metabolism of albendazole to a similar extent in a non-enantioselective manner. In consequence, there was a significant reduction in the plasma concentration of the active metabolite of albendazole, albendazole sulfoxide.

Cimetidine

The poor intestinal absorption of albendazole, which may be enhanced by a fatty meal, contributes to difficulties in predicting its therapeutic response in echinococcosis. The effect of cimetidine co-administration on the systemic availability of albendazole has been studied in six healthy men. After an overnight fast, a single oral dose of albendazole (10 mg/kg) was administered on an empty stomach with water, a fatty meal, grapefruit juice, or grapefruit juice plus cimetidine. The systemic availability of albendazole was reduced by cimetidine. There were no adverse events. These results are consistent with presystemic metabolism of albendazole by CYP3A4.

Albendazole: Organs and Systems

Nervous system

Used in the treatment of neurocysticercosis, albendazole (like praziquantel) can cause a CSF syndrome characterized by fever, headaches, meningism, and exacerbation of some or many of the neurological signs of the disease; it is thought to be due to a local reaction to dying and dead larvae and can be attenuated by prednisone.

Since neurocysticercosis is a neurological infection, it is not surprising that when treating it with any drug some of the neurological reactions to that drug (or to the death of the parasite) are particularly pronounced. For example, with a dose of 1.5 mg/kg continued for some time in cases of neurocysticercosis, a majority of patients initially develop intolerance in the form of headache, vomiting, fever, and occasionally diplopia and meningeal irritation. Even shorter and less intensive treatment has produced similar effects. However, all of these symptoms are probably due to the death of the parasite, and if therapy is continued they usually disappear within a few days. Nevertheless, they can be alarming and demand treatment. Data from large studies mention somnolence and even transient hemiparesis as incidental adverse effects.

Very rarely, in cases of neurocysticercosis, the reaction of the nervous system to the death of the parasite is extremely violent. In one case cerebral edema resulted in permanent neurological damage, while other patients have suffered hydrocephalus or acute intracranial hypertension requiring treatment, for example with glucocorticoids or mannitol.

Albendazole has sometimes aggravated extrapyramidal disorders or precipitated seizures in patients with prior epileptic symptoms. The risk of intracranial hypertension has led some to suggest that glucocorticoids should be given preventively when using albendazole in neurocysticercosis; however, dexamethasone can interact with albendazole, increasing its plasma concentrations, and it is not clear whether this might produce new problems.

Encephalopathy is an adverse event related to the treatment of L. loa with diethylcarbamazine or ivermec-tin, and it has also been related to albendazole.

A 55-year-old woman from Cameroon took oral albendazole 200 mg bd for a symptomatic L. loa infection with microfilaremia of 152 microfilariae/ml and a Mansonella perstans infection of 133 microfilariae/ml. Three days after the start of therapy she developed an encephalopathy. Albendazole was withdrawn and she recovered without any specific treatment within the next 16 hours. On day 4, the L. loa microfilarial count was 29 microfilariae/ml.

The clinical presentation, the interval after starting treatment, the evolution of the episode, and the results of cerebral spinal fluid analysis and electroencephalography in this case were similar to those seen in cases of encephalopathy following treatment of L. loa with ivermectin or diethylcarbamazine. However, pretreatment filaremia was relatively low and L. loa microfilariae were not detectable in the cerebral spinal fluid. Thus, pre-existing conditions might increase the susceptibility to encephalopathy.

Sensory systems

An allergic conjunctivitis was seen in cases of industrial occupational skin reactions to albendazole.

Hematologic

There have been various reports of bone marrow depression. In one study two of 20 patients had a reversible drop in leukocyte count. Pancytopenia, reversible on withdrawal, has been documented in an elderly woman. Even with high doses neutropenia occurs in under 1% of cases. In the older literature an occasional hema-tological death was reported.

A megakaryocytic thrombocytopenia attributed to albendazole has been reported.

A 25-year-old woman who had been taking albendazole 13 mg/kg/day for 5 months for hepatic and pulmonary echinococcosis developed fatigue, bleeding gums, and prolonged menstrual bleeding. She had ecchymoses and petechiae over her legs, marked thrombocytopenia (10 x 109/1), a mild iron deficiency anemia, and a normal leukocyte count. There was no antiplatelet immu-noglobulin. A bone marrow aspiration showed absent megakaryocytes with normal granulocytes and mild erythroid hyperplasia. A cytogenetic study of the bone marrow showed normal karyotype and immunopheno-type. The albendazole was withdrawn and oral iron given. At follow-up 2 months later all laboratory abnormalities had resolved.

Gastrointestinal

With a single oral dose of albendazole 400 mg, there is usually little more in the way of adverse effects than mild gastrointestinal disturbances (notably epigastric pain or dry mouth), occurring only in about 6% of patients in some large series; a few patients have abdominal pain. With higher doses, irritation of the central nervous system can lead to nausea and vomiting.

Diarrhea occurs in a few patients taking albendazole and is usually mild. However, a typical case of pseudomembranous colitis has been documented, although the patient also had AIDS and intestinal microsporidiosis and had taken a number of other drugs; the complication responded to vancomycin.

Liver

Even in single low doses a transient increase in transaminase activities has been repeatedly reported, generally affecting up to 13-20% of patients taking albendazole. At the higher doses some evidence of moderate hepatitis has been claimed to be present in almost all patients, but in one series with high doses of albendazole or mebendazole for echinococcosis only 17% had a (generally slight) increase in serum transaminases, and a fair number of these had pre-existent liver disorders. Like various other adverse effects, the increase in transaminases may be attributable to the breakdown of liver cysts; it is almost always reversible and is usually not a reason for withdrawal; it does not become more marked during long-term treatment. A very occasional individual develops j aundice or some other manifestation of hepatitis.

Skin

A generalized rash has sometimes been seen in patients taking albendazole, and skin complications (including urticaria and contact dermatitis) are a potential problem in employees in the pharmaceutical industry if they undergo heavy exposure to the drug.

A 38-year-old woman with cough, eosinophilia, and pulmonary infiltrates due to visceral larva migrans from Toxocara earns infection took albendazole 600 mg for 8 weeks and developed slight transient skin eruptions.

Stevens-Johnson syndrome was reported in a man who took albendazole 400 mg/day for toxocariasis.

Hair

There are various well-documented reports of reversible alopecia in patients taking albendazole, which in one study occurred in 2% of cases and in another study in one case of 20.

• Severe alopecia has been described in an almost 3-year-old child who took albendazole 400 mg/d for 3 days; 2 months later alopecia developed and resolved within 1 month.
• When one woman took 400 mg bd for 10 months for hydatid disease, she lost much of her hair; no other likely cause could be identified, and her hair growth recovered when the drug was stopped.

Oddly, however, a fair proportion of patients when specifically questioned seem to remark that their hair growth has actually improved during treatment.

Musculoskeletal

Myalgia and arthralgia can occur in patients taking albendazole. However, these symptoms are often features of the disease being treated.

Dosage forms of Albendazole:
Albenza 200 mg tablet	Albendazole powder

How can i get Albendazole online over the counter?

You can buy Albendazole OTC in online drugstore with low cost.

Therapeutic classes of Albendazole:

Anthelmintics, Anticestodal Agents, Antiprotozoal Agents, Tubulin Modulators

Delivery

Australia, Canada, Mexico, New Zealand, USA, Europe [Belgium, France, Norway, Holland, Ireland, Spain, Switzerland, Great Britain (UK), Italy] and etc.