Aminoglycosides are excreted by glomerular filtration and have a serum half-life of 2 to 3 h; the half-life increases exponentially as the GFR falls (eg, in renal insufficiency, in the elderly).
Madagascar is the world's major natural vanilla producer, accounting for about 75% of production. Cloves are the third main export crop, grown mostly by smallholders. Production follows a 4-year cycle with 2â3 years of high output followed by one year of low production.
Coca, opium poppies and cannabis are significant black market cash crops, the prevalence of which varies. In the United States, cannabis is considered by some to be the most valuable cash crop.