Prescrire international
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Prescrire international · Oct 2002
Comparative StudyAtovaquone + proguanil: new preparation. Second-line antimalarial combination.
(1) Quinine, halofantrine and mefloquine are effective treatments for most cases of uncomplicated Plasmodium falciparum malaria. (2) The choice of drug for prevention of P. falciparum malaria in highly endemic regions depends on the risk of chloroquine resistance, and possibly mefloquine resistance. The reference treatments are the chloroquine + proguanil combination, and mefloquine. (3) Marketing authorisation has been granted in France for the atovaquone + proguanil combination, in curative and preventive treatment of P. falciparum malaria. (4) The efficacy of the atovaquone + proguanil combination in uncomplicated malaria is similar to that of other treatments. Some strains of malaria seem to have reduced sensitivity. (5) The atovaquone + proguanil combination is also effective as prophylaxis, but there are no clinical trials showing whether it is equivalent to or better than other preventive treatments in non immune travellers. (6) According to the French licensing terms, atovaquone + proguanil prophylaxis can be stopped 7 days after leaving an endemic area, rather than 3-4 weeks with other drugs. ⋯ In contrast, curative treatment with quinine is cheap, and is fully refunded. (11) Mefloquine and quinine remain the treatments of choice for uncomplicated malaria where there is chloroquine resistance. The atovaquone + proguanil combination is useful if mefloquine and quinine are contraindicated; unlike halofantrine, this combination does not carry the risk of serious drug interactions. In the prophylactic setting, the lack of experience with atovaquone means it should only be used as a second line option, after mefloquine, for short-term prophylaxis in areas with a high prevalence of chloroquine resistance.
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Prescrire international · Aug 2002
Gabapentin: new indication. In postherpetic neuralgia when amitriptyline fails.
(1) Postherpetic pain is infrequent, but the incidence increases with age. (2) The reference treatment for postherpetic pain is oral amitriptyline or desipramine. (3) Gabapentin, an antiepileptic agent, is the first drug to be granted specific approval in France for the treatment of postherpetic pain. (4) In two placebo-controlled trials, gabapentin at a dose of between 1 800 and 3 600 mg/day halved the intensity of pain in about one in three patients. In comparison, pain improved in about 50% of patients taking amitriptyline in clinical trials. (5) Both gabapentin and amitriptyline provoke sedation, but dizziness and peripheral oedema are more frequent on gabapentin, while atropinic effects predominate with amitriptyline. (6) Daily treatment is 10 times more costly in France. (7) In practice, the standard treatment of postherpetic pain remains oral amitriptyline or desipramine. Gabapentin is an alternative, given its different safety profile.
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Prescrire international · Aug 2002
Oral transmucosal fentanyl: new preparation. For breakthrough cancer pain when morphine fails.
(1) Some cancer patients suffer occasional breakthrough pain despite well-conducted opiate treatment, warranting the use of immediate-release oral morphine. (2) A fentanyl preparation for oral transmucosal administration has just been granted this indication in France. (3) The evaluation file mainly contains results from a randomised double-blind cross-over trial comparing transmucosal fentanyl with oral morphine tablets in cancer patients. It showed a small gain in terms of rapidity and efficacy of pain relief with fentanyl relative to morphine, but this was of dubious clinical relevance. (4) The adverse effects of oral transmucosal fentanyl are those of all opiates, such as drowsiness, dizziness, nausea, vomiting and confusion. (5) The oral transmucosal fentanyl preparation has the taste and appearance of a lollipop, and may therefore be attractive to children. The packaging seems to take this risk into account, but precautions must be taken to keep this treatment away from children, especially after opening. (6) Immediate-release oral morphine remains the standard treatment for breakthrough pain in patients receiving opiate therapy. If it is inadequate, oral transmucosal fentanyl may sometimes be slightly better.
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Prescrire international · Aug 2002
Oral pilocarpine: new preparation. Xerostomia after radiation therapy: moderately effective but costly.
(1) Dry mouth (xerostomia) is a frequent complication of radiation therapy for cancers of the ear nose and throat. Local measures such as saliva substitutes and anetholtrithione are either moderately effective, inadequately evaluated or little better than placebo. (2) Marketing authorization has been granted in France for an oral formulation of pilocarpine, an old parasympathomimetic agent, in the treatment of radiotherapy-induced xerostomia. (3) According to the results of two double-blind trials, pilocarpine (15-30 mg/day) improves symptoms in about 50 % of patients, compared to improvement in 25% of patients taking placebo. ⋯ It is not known whether pilocarpine helps prevent the complications of xerostomia. (4) Most adverse effects of pilocarpine are due to its parasympathomimetic effects, such as sweating, urinary frequency, flushing, rhinitis and nausea. Pilocarpine must therefore be used with caution in patients with asthma, cardiac arrhythmia, iridocyclitis, and closed-angle glaucoma. (5) In France, this pilocarpine formulation costs 18 times more than a preparation of pilocarpine 2% eye drops used orally (off licence). (6) In practice, patients needing symptomatic treatment of xerostomia after radiotherapy may benefit from oral pilocarpine but, given its limited efficacy and its adverse effects, other local treatments should be tried first.
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Prescrire international · Jun 2002
Comparative StudyTenecteplase: new preparation. Another thrombolytic agent for myocardial infarction: a slightly simpler treatment.
(1) Alteplase is the standard thrombolytic agent for treating patients under 75 years with myocardial infarction if they are seen within 6 hours. It is given as an intravenous infusion over 90 minutes in combination with aspirin and unfractionated or low-molecular-weight heparin. (2) Tenecteplase has been authorized for use in myocardial infarction as an intravenous bolus over 5 to 10 seconds. (3) The evaluation file on tenecteplase contains data from three dose-finding studies and one double-blind trial against alteplase in nearly 17 000 patients. ⋯ The combination of tenecteplase and enoxaparin makes treatment simpler, which could be particularly useful prior to hospital admission. A smaller trial of alteplase + enoxaparin against alteplase + unfractionated heparin gave similar findings. (6) In practice, tenecteplase has the advantage of a more convenient administration; a very large trial strongly suggests that its effects are almost identical to those of alteplase.