There are articles, usually about young people but sometimes about the elderly. It's not very dramatic or interesting compared to an impulsive suicide, and the people who do it rarely are considered of interest unless they're rich and choose Dignitas.
I do believe journalists feel there is little benefit to reporting about it too, and possible harm to be done by reporting on the method and that it is obtainable. In my country at least, the typical guideline on suicide reporting is that there must be some positive or useful angle—which is played with loosely, to be sure, but still.
If you read articles about suicides you will soon realise the average N suicide has little in common with them. It is not at all sensational. N articles typically focus on the evils of the dealers and right to die groups, the tragedy to the family, etc. or the usual Exit-related angle of it.
Many people die without their suicides being reported in the news. And there are probably more articles than we know of: 'overdose' is a vague word and I don't look any further into it.
Finally, yes, it is a rare method compared to all the other suicides. Look up the suicide stats for your area and you might be surprised.
