Efficacy and safety of medicines based on Cannabis sativa extract for the treatment of eplepsy in Rett Syndrome

ABSTRACT

Strength of recommendation: Weak against the use of technology.

Technology: Medicine and products based on Cannabis sativa.

Indication: Treatment of Rett syndrome.

Characterization of the technology: Enriched cannabidiol extracts with low delta-9-tetrahidrocanabinol (THC) content (up to 1%).

Question: Medications based on Cannabis sativa are effective and safe for the treatment of epilepsy in patients with Rett syndrome compared with anticonvulsants available in SUS?

Search and analysis of scientific evidence: We searched The Cochrane Library (via BIREME), Medline (via Pubmed), Lilacs, Centre for Reviews and Dissemination (CRD) and Tripdatabase databases aiming to find studies of Cannabis sativa treatment for Rett syndrome. We also selected Health Technology Assessments (HTA) on sites of international agencies and REBRATS. We also performed an additional search of clinical trials for the treatment of epilepsy with drugs containing known concentrations of cannabinoids extracted from Cannabis sativa.

Summary of results of selected studies: No studies met the criteria for participant (patients diagnosed with Rett syndrome with episodes of epilepsy), intervention (medications based on Cannabis sativa), comparison (placebo drugs for epilepsy in Rett syndrome were identified – valproic acid, carbamazepine, clobazam, clonazepam, ethosuximide, phenytoin, phenobarbital, gabapentin, lamotrigine, primidone, topiramate, vigabatrin) and outcome (psychomotor improvement, reduction of seizures and adverse events). The four studies found in the supplementary search on the plant extract usage in the treatment of epilepsy had small sample, were of poor quality and inconclusive: two presented results in of favor the use of cannabidiol and two showed no differences among the groups.

Recommendations: The intensity of the recommendation is weak against the use of medicine preparations of Cannabis sativa due to the lack of scientific evidence of efficacy and safety of plat extracts with high concentration of cannabidiol and low concentrations of delta-9-tetrahidrocanabinol. Because of the high concentration of THC, we strongly recommend against the use of the unpurified extract of Cannabis sativa. This position is guided by the possibility of the occurrence of adverse events such as deficits in cognitive development and seizure.

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