The program is off to a slow start: Only 150 physicians have completed the required registration with the state, and only eight of 20 dispensaries expect to open on Thursday. The remaining 12 dispensaries are expected to open by month’s end. “Our pharmacists are ready,” said Nicholas Vita, CEO of Columbia Care NY, which intends to open its first dispensary this week near Manhattan’s Union Square, followed by other locations in Suffolk, Clinton and Monroe counties. “Our product is ready. It’s been tested by the state and validated.” To receive medical cannabis a person must have one of several qualifying conditions, obtain certification from a physician registered with the program and apply for a registry identification card from the state’s Department of Health. The drugs will come in the forms of capsules and oils and tinctures that can be vaporized or used in inhalers. The names of the physicians able to authorize the drug are being withheld by the state. The Department of Health announced Tuesday it would soon post a list of those physicians willing to be publicly identified. The state’s cautious approach was intended to address concerns about the risk that marijuana would be diverted for recreational uses. “Our program ensures the availability of pharmaceutical-grade medical marijuana products for certified patients and establishes strict regulatory controls to protect public health and safety,” state Health Commissioner Howard Zucker said Tuesday. Many patients and advocates of medical marijuana have expressed frustration not only with the 18-month implementation period but also with restrictions on the number of dispensaries and types of qualifying conditions.