Albendazole (Page 2 of 4)
6 ADVERSE REACTIONS
6.1 Clinical Trials Experience
Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice.
The adverse reaction profile of albendazole differs between hydatid disease and neurocysticercosis. Adverse reactions occurring with a frequency of 1% or greater in either disease are described in Table 2 below.
These symptoms were usually mild and resolved without treatment. Treatment discontinuations were predominantly due to leukopenia (0.7%) or hepatic abnormalities (3.8% in hydatid disease). The following incidence reflects adverse reactions that were reported to be at least possibly or probably related to albendazole.
Adverse Reaction | Hydatid Disease | Neurocysticercosis | |
Gastrointestinal | |||
Abdominal Pain | 6 | 0 | |
Nausea | 4 | 6 | |
Vomiting | 4 | 6 | |
General disorders and administration site conditions | |||
Fever | 1 | 0 | |
Investigations | |||
Elevated Hepatic Enzymes | 16 | less than 1 | |
Nervous system disorders | |||
Dizziness | 1 | less than 1 | |
Headache | 1 | 11 | |
Meningeal Signs | 0 | 1 | |
Raised Intracranial Pressure | 0 | 2 | |
Vertigo | 1 | less than 1 | |
Skin and subcutaneous tissue disorders | |||
Reversible Alopecia | 2 | less than 1 |
The following adverse events were observed at an incidence of less than 1%:
Blood and Lymphatic System Disorders: There have been reports of leukopenia, granulocytopenia, pancytopenia, agranulocytosis, or thrombocytopenia [see Warnings and Precautions (5.1)].
Immune System Disorders: Hypersensitivity reactions, including rash and urticaria.
6.2 Postmarketing Experience
The following adverse reactions have been identified during post-approval use of albendazole. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure.
Blood and Lymphatic System Disorders: Aplastic anemia, bone marrow suppression, neutropenia.
Eye Disorders: Vision blurred.
Gastrointestinal Disorders: Diarrhea.
General System Disorders: Asthenia.
Hepatobiliary Disorders: Elevations of hepatic enzymes, hepatitis, acute liver failure.
Musculoskeletal and Connective Tissue Disorders: Rhabdomyolysis.
Nervous System Disorders: Somnolence, convulsion.
Renal and Urinary Disorders: Acute renal failure.
Skin and Subcutaneous Tissue Disorders: Erythema multiforme, Stevens-Johnson syndrome.
7 DRUG INTERACTIONS
7.1 Dexamethasone
Steady-state trough concentrations of albendazole sulfoxide were about 56% higher when 8 mg dexamethasone was co-administered with each dose of albendazole (15 mg/kg/day) in 8 neurocysticercosis patients.
7.2 Praziquantel
In the fed state, praziquantel (40 mg/kg) increased mean maximum plasma concentration and area under the curve of albendazole sulfoxide by about 50% in healthy subjects (n = 10) compared with a separate group of subjects (n = 6) given albendazole alone. Mean Tmax and mean plasma elimination half-life of albendazole sulfoxide were unchanged. The pharmacokinetics of praziquantel were unchanged following co-administration with albendazole (400 mg).
7.3 Cimetidine
Albendazole sulfoxide concentrations in bile and cystic fluid were increased (about 2-fold) in hydatid cyst patients treated with cimetidine (10 mg/kg/day) (n = 7) compared with albendazole (20 mg/kg/day) alone (n = 12). Albendazole sulfoxide plasma concentrations were unchanged 4 hours after dosing.
7.4 Theophylline
Following a single dose of albendazole (400 mg), the pharmacokinetics of theophylline (aminophylline 5.8 mg/kg infused over 20 minutes) were unchanged. Albendazole induces cytochrome P450 1A in human hepatoma cells; therefore, it is recommended that plasma concentrations of theophylline be monitored during and after treatment.
8 USE IN SPECIFIC POPULATIONS
8.1 Pregnancy
Risk Summary
Based on findings from animal reproduction studies, albendazole may cause fetal harm when administered to a pregnant woman. However, available human data from a small number of published case series and reports on the use of multiple-dose albendazole in the 1st trimester of pregnancy, and several published studies on single-dose albendazole use later in pregnancy, have not identified any drug-associated risks for major birth defects, miscarriage, or adverse maternal or fetal outcomes. In animal reproductive studies, oral administration of albendazole during the period of organogenesis caused embryotoxicity and skeletal malformations in pregnant rats (at doses of 0.10 times and 0.32 times the maximum recommended human dose based on body surface area in mg/m2) and pregnant rabbits (at doses of 0.60 times the maximum recommended human dose based on body surface area in mg/m2). Albendazole was also associated with maternal toxicity in rabbits (at doses of 0.60 times the recommended human dose based on body surface area in mg/m2) (see Data). Advise a pregnant woman of the potential risk to the fetus.
The estimated background risk of major birth defects and miscarriage for the indicated population is unknown. All pregnancies have a background risk of birth defects, loss, or other adverse outcomes. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2 to 4% and 15 to 20%, respectively.
Data
Animal Data
Albendazole has been shown to be teratogenic (to cause embryotoxicity and skeletal malformations) in pregnant rats and rabbits. The teratogenic response in the rat was shown at oral doses of 10 and 30 mg/kg/day (0.10 times and 0.32 times the maximum recommended human dose based on body surface area in mg/m2 , respectively) during organogenesis (gestation days 6 to 15) and in pregnant rabbits at oral doses of 30 mg/kg/day (0.60 times the maximum recommended human dose based on body surface area in mg/m2) administered during organogenesis (gestation days 7 to 19). In the rabbit study, maternal toxicity (33% mortality) was noted at 30 mg/kg/day. In mice, no teratogenic effects were observed at oral doses up to 30 mg/kg/day (0.16 times the recommended human dose based on body surface area in mg/m2), administered during gestation days 6 to 15.
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