Translated and edited from: Martin Woodbridge, A primer to medicinal cannabis (an introductory text, Bedrocan International, 2018).
The Netherlands has run a medical cannabis programme without a break since 2003. In this programme, doctors prescribe and pharmacies dispense. It is one of the longest-running programmes of its kind anywhere. Two practitioners from the Dutch programme describe three working habits. They prescribe only where the evidence is strong, start with a low dose, and use the pharmacy as a second clinical check on the patient.
Who Is Speaking, and How Much Weight to Give It
Martin Woodbridge, the book’s author, interviewed two Dutch practitioners. One is a pain specialist who worked in anaesthesiology and pain medicine in Leiden, a city in the Netherlands. The other is a pharmacist in The Hague. Their jobs are described as they were in 2018 and may have changed since.
Bedrocan International, a Dutch producer of medicinal cannabis, paid for the book and holds its copyright. The company sold the kind of product the book discusses, so it had a conflict of interest. A Dutch court declared Bedrocan bankrupt in October 2026. Keep this in mind when the practitioners list the benefits.
This article describes practice in another country. It is written for doctors, pharmacists, regulators and licensed operators. It is not a clinical guideline, not a treatment protocol and not medical advice. Two clinicians in one country are a case study. They are not proof that something works.
What you can do: read each point below as “how two Dutch practitioners worked in 2018”. Before you act on any clinical point, check it against current guidance.
Translator’s note: the rules in Thailand (October 2026).
- Cannabis flower (ช่อดอกกัญชา) is a controlled herb. This comes from the Notification of the Ministry of Public Health Re: Controlled Herbs (Cannabis), B.E. 2568, which was issued under the Thai Traditional Medicine Protection Act B.E. 2542. It has been in force since 26 June 2025.
- Flower may be sold only against a PT 33 (ภ.ท.33) prescription from an authorised practitioner. One prescription covers no more than 30 days.
- The notification also requires that flower sold must come from a source certified under the GACP standard. GACP means Good Agricultural and Collection Practice, the farming and record-keeping standard for medicinal plants.
- Advertising flower and selling it online are prohibited.
- Two Ministerial Regulations of B.E. 2569 followed in April 2026. The regulation on cannabis or hemp extracts came into force on 26 April 2026. The Ministerial Regulation on Controlled Herbs (No. 2) came into force on 30 April 2026 and sets stricter licence criteria for cannabis flower.
- The draft Cannabis Control Act is not yet law. The Cabinet approved the draft on 22 September 2026 and sent it to the House.
In Thailand, every clinical decision described below is made by the prescribing practitioner, within these rules.
Translator’s note: why growers should read this. Most readers of this forum are growers, from licensed GACP farms to people growing at home. In Thailand, a farm’s flower reaches a patient only through a PT 33 prescription and a dispensary. Section 3 explains what the prescriber relies on: an active-ingredient content that is known and controlled, and a product free of contamination.
For a licensed farm, this means three practical things:
- Keep records for each batch, so a dispensary can trace any product back to the batch it came from.
- Have every batch tested, and learn to read the certificate of analysis (the lab report) yourself.
- Use only pesticides registered with the Department of Agriculture (กรมวิชาการเกษตร), and follow the label. See what you may legally spray under Thai GACP.
For a home grower, the key point is the law on selling. Flower may be sold only against a PT 33 prescription. Under Section 78 of the 1999 Act, selling a controlled herb without a licence carries up to 1 year in prison and/or a fine of up to 20,000 baht. If you or someone in your family uses cannabis for a health problem, tell your doctor. Section 5 shows what goes wrong when patients use it without medical supervision.
1. The Counselling Sequence
The most useful lesson from this pharmacist is her view of her own job. In her view, the pharmacist’s role is as important as the prescriber’s. Her work had four parts:
- Supporting the prescriber with a medication review, which means checking all of the patient’s medicines together.
- Discussing benefits and risks with the patient.
- Reducing misuse and harm.
- Collecting feedback on safety, how well the medicine worked, and any side effects.
Her counselling sequence can be used in any country:
- Ask what the patient already knows about medical cannabis. Start from what they believe, not from a fixed script.
- Explain how the medicine works, how to use it, the dosing plan, possible side effects and safe storage.
- Check that the patient understands possible interactions with their other medicines. Also check that they understand the contraindications, the situations in which they should not use it.
- At the next visit, ask how it went. Focus on whether it helped and what side effects appeared.
Staff skip step 1 more often than any other step. Her advice to pharmacists new to the field explains why it matters. Get trained or read widely, she said, because patients usually know a great deal but also believe some wrong information. Step 1 tells you which of their beliefs are correct and which are wrong. Without it, your explanation may not correct the wrong beliefs.
Her pharmacy allowed one to two weeks before judging whether the medicine was working. The body absorbs and clears THC very differently from one person to the next. It also differs between products and between ways of taking it (see cannabinoid pharmacokinetics). So treat the one-to-two-week period as one pharmacy’s own rule, not as a measured fact.
Translator’s note: in Thailand, step 2 (safe storage) needs extra attention. Room temperatures of 30–35 °C and high humidity in the rainy season can spoil flower kept in a hot room or an open bag. Tell patients to keep their medicine sealed, in a cool and dark place, out of reach of children. For details, see storage: humidity, light, oxygen and shelf life.
What you can do: if you work at a dispensary, put the four steps on a printed checklist for every new patient. At the follow-up visit, write down the effect and side effects the patient reports. That record shows whether the product is helping. It also gives the prescriber facts instead of impressions.
2. Spotting Misuse From Dispensing Records
The pharmacist said misuse was rare. Her pharmacy spotted it by tracking how much each patient received and how often they came back. When it found misuse, the pharmacist first agreed on a plan with the patient. If that did not work, the pharmacy asked the prescriber to find a solution.
She saw pharmacovigilance as a core part of a pharmacist’s job. Pharmacovigilance means collecting and assessing reports of side effects from healthcare workers and patients. Giving patients truthful information about benefits and risks was another core part of the job.
The prescriber described the same problem from the doctor’s side. At one time, Dutch health insurers paid for medical cannabis for many patients. During that time, some patients came with vague medical reasons. Some saw a prescription as a cheap way to get a drug they were already using. When he raised misuse, some pushed hard and reacted angrily. His response was to apply the same rules to every patient, not to rely on gut feeling. He prescribed only for conditions with enough evidence. When misuse became clear, he discussed it openly.
This check needs no special technology. It only needs dispensing records and someone who reads them regularly.
Translator’s note: this habit is the most directly useful one in this article for Thai dispensaries. PT 33 prescriptions cover at most 30 days. Dispensaries also face closer checks after the PT 33 enforcement drive reported in June 2026.
What you can do: for each patient, record the date, the product and the quantity at every sale. Review these records on a fixed day each month. Look for patients who come back earlier than their prescription allows or who receive more each time. Those are the cases to raise with the patient first and then with the prescriber.
3. The Prescriber’s Experience
In 2018 the pain specialist in Leiden mainly saw two groups of patients. The first was people with advanced cancer who had lost their appetite, had nausea and vomiting, and were already taking several medicines. The second was people with central neuropathic pain (nerve pain caused by damage in the brain or spinal cord) whom common pain drugs had not helped. For the evidence on pain, see cannabis and chronic pain.
Start where the evidence is strong. His advice to new prescribers was to stay with conditions where the evidence is strong. Treat a defined group of adults first, and gain experience where the expected effect is known. In his view, people who already use cannabis recreationally are not the right group to start with. They may push for prescriptions for conditions that are not well supported. His point concerns how a new prescriber builds skill safely. He was not judging those patients.
Benefits, and their limits. He listed these benefits:
- Pain relief in nerve pain.
- Less nausea and better appetite, depending on the product.
- A calming effect from some varieties.
- No known organ damage in adults, apart from a possible risk to mental health. He contrasted this with common anti-inflammatory painkillers (NSAIDs, such as ibuprofen), which can cause organ damage when used inappropriately.
The last point needs balance. Cannabis has other documented side effects. They include cannabinoid hyperemesis syndrome (repeated bouts of severe vomiting in long-term users), heart and blood-vessel events, and dependence. He himself links smoking to heart and blood-vessel events (see below). The contraindications article linked in section 1 covers these risks. Every benefit on his list eases symptoms. None of them treats the underlying disease.
Practices he said give better results:
- Start with a low dose, in a quiet and comfortable place. For patients who have never used cannabis, psychological reactions are the main concern. The setting where the patient takes the first dose matters as much as the dose.
- For pain relief, vaporised flower rather than taking it by mouth, in the Dutch setting. Vaporising heats the flower without burning it. He gave three reasons: the dose is more accurate, the effect starts faster, and no smoke is produced. See routes of administration.
- Never smoke it. He linked smoked cannabis to heart attack and stroke. He gave two causes. Cannabis stimulates the heart and blood vessels, which is dangerous for vulnerable hearts. Smoke also adds carbon monoxide to the blood (carboxyhaemoglobin), so the blood carries less oxygen.
- Know exactly what you prescribe. Flower from legally regulated producers assures the patient that the active-ingredient content is controlled and that the product is free of contamination. For the manufacturing standards behind this, see EU-GMP and PIC/S GMP. GMP means Good Manufacturing Practice.
Translator’s note on routes in Thailand: Thailand bans the import and sale of e-cigarettes, and people found with them can be prosecuted under customs law. The sources we checked do not say clearly whether a herbal vaporiser falls under this ban. So do not assume a vaporiser is a legal way to take cannabis in Thailand. Use only the routes written on the PT 33 prescription and in the registration of the product dispensed.
Two kinds of first visit. He rarely raised cannabis himself at a first visit with an older patient who had never used it. If the patient was suitable and other treatments had not given enough relief, he mentioned it as one option. He then gave the patient and family time to think before the next appointment.
The second kind was an experienced user who actively asked for cannabis. Such patients sometimes made other treatments sound worse than they were. He discussed cannabis fully with them at the first visit. The main question was whether the patient met the criteria for a prescription.
What you can do: if you prescribe, write the condition and its evidence in the patient record before the first prescription. Apply the same criteria to every patient. If you run a GACP farm that supplies dispensaries, give a lab certificate with every batch. The prescriber cannot “know what they prescribe” without one.
4. Dosing and Safety: Principles, Not Numbers
The pharmacy wrote its dosing advice for standardised Dutch products sold in 2018. The original article does not repeat those figures, and neither does this rewrite. A dose figure means nothing clinically without the product’s THC and CBD content. It also cannot be applied to a different product. Only the principle carries over: start low, raise the dose slowly in small steps, and dose by the specific product prescribed. See start low, go slow.
For inhaled cannabis, the pharmacy gave patients three instructions:
- Wait between inhalations.
- Stop at the first sign of a psychoactive effect, the feeling of being “high”. It means the dose is already too high.
- After switching to a different variety, work out the dose again. This matters most when switching from a weaker variety to a stronger one.
The pharmacist named these contraindications: schizophrenia, heart rhythm problems (arrhythmia) and other heart disease. She saw these as the greatest risks:
- Intoxication.
- Psychotic symptoms, especially in psychiatric patients.
- Worsening depression.
- Prescribing for older patients.
She also noted that the long-term effects in children are unknown.
The prescriber’s main concern was interactions with other medicines that slow the brain and cause drowsiness. Strong painkillers (opioids) are among them. Together with cannabis, they can make older patients much more drowsy.
The pharmacist also warned about interactions through CYP450, a group of liver enzymes that break down many medicines. Cannabis can change how fast these enzymes break down other drugs. The drug interactions and contraindications articles linked in section 1 cover both topics in detail.
What you can do: if you are a patient, keep a simple diary of the product name, the dose, the time and how you felt. Bring it to every visit, together with a list of all your other medicines. With this, the doctor can adjust your dose based on your actual responses.
5. What Patients Report
The book also summarises interviews by Frédérique Bawin, a researcher at Ghent University in Belgium. She interviewed people in Flanders, the Dutch-speaking north of Belgium, who said they used cannabis for medical reasons. Her full results are in her doctoral thesis, Self-reported medicinal cannabis use in Flanders: a study of user profiles and patterns of use (Ghent University, 2020).
The book also cites a Dutch patient questionnaire from 2016. That was a university student project, not a peer-reviewed study. The editors of the original article could not trace it, so its figures are not repeated here.
It eases symptoms; it does not cure. Patients said cannabis reduced their symptoms but did not remove them. Most did not see it as a cure. Some said it helped only partly, or not at all, for certain symptoms. With pain, the pain stayed but became bearable. Higher doses relieved more pain but caused more side effects. Some patients said ordinary painkillers worked better. They still chose cannabis because its side effects suited them better.
The gap between patient and doctor. According to the book’s account of this research, many patients obtained cannabis themselves and did not tell their family doctor. They chose the product, dose and route with no supervision. This was not what they wanted. They wanted medical supervision but found few doctors with experience of cannabis. When they did see a doctor, they often got a prescription and only very general advice.
The book describes this as the doctor–patient relationship turned upside down: the patient ends up informing the doctor. The four-step sequence in section 1 is designed to close exactly this gap.
Translator’s note: in Thailand, the same gap appears when patients obtain flower outside the PT 33 system. In that case they also do not know the product’s THC content or whether it is contaminated.
What you can do: if you use cannabis for a health problem, tell your doctor what you use, how much and how often. If you grow your own, say so. Home-grown flower has an unknown content, and your doctor needs that information to check interactions.
6. What Carries Over to Thailand, and What Does Not
| Practice | Does it carry over to Thailand? |
|---|---|
| Prescribe only for conditions with enough evidence | Yes, in any country |
| Start low, raise slowly, dose by product; quiet setting for first-time patients | Yes |
| Allow time before judging the effect, not day 2 | Yes, as a principle; the right time varies by patient and product |
| Avoid smoking | Yes, as a clinical principle |
| Vaporising | Not safely. Thailand bans the import and sale of e-cigarettes, and it is unclear whether herbal vaporisers are covered (see section 3); use only the routes on the PT 33 prescription and in the product registration |
| Pharmacist as a second clinical check | Yes in principle; depends on how dispensing is organised locally |
| Track quantity and frequency to spot misuse | Yes; needs only dispensing records |
| Ask first what the patient already knows | Yes, and it costs nothing |
| Dutch drop counts and volumes | No. They apply only to one product and formulation |
What you can do: use the “Yes” rows as a checklist when you set up or review a dispensing service. Remove any step that depends on the “No” rows.
7. The Limits of This Source
This account comes from two practitioners in one country, recorded in 2018. The book was funded by Bedrocan International, which also holds its copyright. The book itself says its case studies depend on their local setting. It also says they should not be the basis for prescribers’ and pharmacists’ decisions.
The clinical data behind the book was current up to June 2018, and the field has changed since then. Use the book as a description of how an established programme works, which can help when you design a service. It does not replace guidance from the authority that regulates you.
What you can do: before you change how you prescribe or dispense, read the current Thai legal texts yourself. Start with Thai cannabis law and compliance: read the original legal texts.
8. The Question for Thailand
When the official route is hard to reach, patients keep using cannabis anyway. They obtain it themselves, without supervision, from products of unknown content. This puts patient safety at risk.
The editors of the original article hold the following view, which is an opinion and not a research finding. The number of practitioners trained and confident enough to use PT 33 properly may now limit the system as much as the rules do. This may remain true even as the rules become stricter.
Please reply under this topic:
- Clinicians and pharmacists in Thailand and the region: which part is hardest to copy where you work? Is it training, consistent products, time for proper counselling, or record-keeping?
- Patients: did your prescriber give you specific guidance, or only general advice?
- Growers who supply licensed dispensaries: what do prescribers or pharmacists ask you about your batches?
Asiannabis Community: general information for professional reference, not medical advice or a clinical guideline. In Thailand, cannabis flower is supplied only on prescription by an authorised practitioner using form PT 33.
References
- Martin Woodbridge, A primer to medicinal cannabis (an introductory text, Bedrocan International, 2018). Funded by Bedrocan International, which holds its copyright.
- Frédérique Bawin, Self-reported medicinal cannabis use in Flanders: a study of user profiles and patterns of use, doctoral dissertation, Ghent University, 2020.