Cycling South Africa reports that veteran cyclist Joe van der Westhuizen returned an adverse analytical finding in an in-competition test conducted by the South African Institute for Drug-Free Sport (SAIDS) on 4 October 2014 at the Engen Cycle in the City Race.
The analytical report confirmed the presence of the Anabolic Agent, Clenbuterol as well as the Glucocorticosteroid, Prednisone and its metabolite Prednisolone in his urine sample.
Mr. Van der Westhuizen waived his right to a hearing and has been found guilty by SAIDS. He received a two-year ban from all sport effective from 4 October 2014 to 3 October 2016.
Cycling South Africa respects the independence of the SAIDS process and respects the outcome. Cycling SA further reiterates its zero-tolerance approach to doping in sport and will continue working with SAIDS in the promotion of a drug-free sport via its awareness programmes and extensive testing.
All cyclists are urged to avail themselves of all the resources available to them to ensure a drug-free career in sport. In addition, all cyclists are advised to exercise extreme caution at all times with regards to any food and/or medical products they may come into contact with.
I got presribed teh inhaler at the same time as the Spiractin (which is, as you say, a diuretic) and the doc just sent in forms. 
Very interesting. Thanks gents for sharing the knowledge.
So judging by what was found in his sample, one can safely assume it was intentional.
Scary and sad stuff.