You are not going to find Clysodrast for sale in the USA, and probably not anywhere else either. The Tannic Acid component was capable of causing fatal liver damage in patients, and evidence as to the effectiveness and Safety of Clysodrast was lacking. As a result Tannic Acid is effectively a banned substance in drug products for internal use. Basically FDA removed Tannic Acid from the Generally Regarded As Safe (GRAS) category, and requires that any product containing tannic acid for internal use go through the formal IND/NDA process for FDA approval.
Given the available evidence, the expense of going through the IND/NDA process, and the known safety issues, the prospects for gaining FDA NDA approval for such a product are zero.
This is what the FDA says about Tannic Acid:
"Code of Federal Regulations TITLE 21--FOOD AND DRUGS
CHAPTER I--FOOD AND DRUG ADMINISTRATION
DEPARTMENT OF HEALTH AND HUMAN SERVICES
SUBCHAPTER C--DRUGS: GENERAL
PART 201 -- LABELING
Subpart G--Specific Labeling Requirements for Specific Drug Products Sec. 201.304 Tannic acid and barium enema preparations.
(a) It has become a widespread practice for tannic acid to be added to barium enemas to improve X-ray pictures. Tannic acid is capable of causing diminished liver function and severe liver necrosis when absorbed in sufficient amounts. The medical literature reports a number of deaths associated with the addition of tannic acid to barium enemas. There is a lack of scientific evidence to establish the conditions, if any, under which tannic acid is safe and effective for use in enemas. Tannic acid for rectal use to enhance X-ray visualization is regarded as a new drug within the meaning of section 201(p) of the Federal Food, Drug, and Cosmetic Act.
(b) In view of the hazards involved when tannic acid is used in barium enemas, any shipments of tannic acid labeled to come within the exemptions under 502(f) of the Act containing such phrases as: "Caution: For manufacturing, processing, or repackaging," "For prescription compounding," or "Diagnostic reagent--For professional use only" will be regarded by the Commissioner of Food and Drugs as misbranded within the meaning of section 502(f) of the Federal Food, Drug, and Cosmetic Act unless the label and the labeling bear conspicuously a warning to the effect: "Warning-- Not for use in enemas."
(c) Any tannic acid intended for use by man and found within the jurisdiction of the Federal Food, Drug, and Cosmetic Act labeled contrary to this section after 60 days from the date of its publication in the Federal Register may be made the subject of regulatory proceedings."
In other words, even if you could get get Clysodrast, using it in an enema is a very bad idea. The FDA tends to be the world leader in drug safety issues, and generally if the FDA issues a ban, most of the regulatory agencies outside the USA will follow suit fairly quickly.