Sidegra is manufactured under license in Thailand by the Government Pharmaceutical Office (GPO), the 50 mg and 100 mg tablets correspond to the same tablets manufactured and distributed internationally as Viagra by Pfizer
generic versions of sildenafil citrate (the active ingredient in Viagra) are manufactured in some other countries, sometimes under license and sometimes by companies following good manufacturing practice (GMP) though not necessarily always, and these products are often not licensed for import into or sale in many major markets, including for example Kamagra in Thailand, so product origin and quality can be challenging to determine, particularly for gel forms which have no equivalent in internationally licensed products.
I may sound like a shill for the drug companies, but I am actually a strong supporter of reliable manufacturers of generics of off-patent drugs or toll manufacturers producing cheaper licensed products locally - indeed a third of the meds I purchase monthly for various ongoing health issues are in this category - and I am certainly not here to cast aspersions on examples of Kamaga available in Thailand and personal decisions to buy such products as I have never tried them, or attempted to verify their source!