Observed therapeutic differences between Vietnam and the United States

It was our last day working in the pharmacy at the Pasteur Clinic in Da Lat and we couldn’t be more thankful for the amount we were able to learn and experience while working with wonderful pharmacists. Our upcoming plans for now include spending our last weekend in Northern Vietnam at the capital, Hanoi, and taking a day to explore Ha Long Bay. Once we return, we look forward to spending our final week in Da Lat working in the injection room, prepping and administering vaccinations to a number of children and adults in the region.
Throughout our time in the pharmacy, we have had several discussions with the pharmacists regarding medications that are commonly used in Vietnam, but are either used for a different indication or not used at all in the United States. Drugs that are commonly used here that are not used at all (and/or are not approved) in the United States include rupatadine (antihistamine), domperidone (dopamine antagonist used for the treatment of nausea), spiramycin (antibiotic/antiparasitic), secnidazole (anti-infective often used for bacterial vaginosis), sulpiride (antipyschotic used for its antiemetic properties), trimebutine (weak opioid agonist used to treat IBS and other gastrointestinal disorders), and ambroxol (used to thin mucus in respiratory illnesses). In addition to these medications, natural supplements are used much more commonly in Vietnam, especially milk thistle and others intended for hepatic protection in hepatitis B and hepatitis C patients. Antiparasitic medications such as albendazole, spiramycin, and ivermectin are also significantly more prominent in Vietnam than they are in the United States.
Below are three different clinical applications of certain drugs or drug classes that are seen commonly in Vietnam.

1. Use of dual antihistamine therapy for the management of acute urticaria
   A common topic of clinical discussion is the use of dual second generation antihistamines for the treatment of urticaria. In Vietnam, it seems as if every patient takes a combination of two of the following: fexofenadine, cetirizine, rupatadine, loratadine, cimetidine (uniquely an H2 receptor antagonist), and levocetirizine. The prescriptions instruct patients to take one in the morning and one at bedtime. Although this may seem logical for the intended purpose of increasing antihistaminic activity in severe cases, it is strictly and expressly recommended against per guidelines in the United States due to the increased potential for antihistamine-related toxicities and adverse effects. In all guidelines we were able to find, the first line treatment is to use a single second generation antihistamine. The American Academy of Allergy, Asthma & Immunology (AAAAI) 2014 guidelines are the only guidelines we we able to find that recommend the use of dual anti-histamine therapy as second line for the treatment of urticaria. According to the World Health Organization (WHO), second line treatment for urticaria includes increasing the dose of mono antihistamine therapy by four times rather than using dual antihistamines and/or H2RAs, such as cimetidine.

A link to the AAAAI step-care approach guidelines for the treatment of urticaria: https://www.aaaai.org/Aaaai/media/MediaLibrary/PDF%20Documents/Practice%20and%20Parameters/Urticaria-2014.pdf
A link to the European Academy of Allergy and Clinical Immunology (EAACI)/Global Allergy and Asthma European Network (GA²LEN)/European Dermatology Forum (EDF)/World Allergy Organization (WAO) guidelines: https://emedicine.medscape.com/article/1050052-guidelines

2. Use of domperidone as an antiemetic in the treatment of nausea and vomiting
After our first day in the pharmacy, we noticed that domperidone is also commonly dispensed in the pharmacy. Since neither of us had heard of this drug before, we decided to do some research on our own. Our search results yielded that domperidone is indicated for nausea and vomiting and acts on dopamine receptors to decrease the effect of the chemoreceptor trigger zone (CTZ) of the medulla oblongata in the brain to decrease activation of the vomiting structures (similarly to drugs like metoclopramide). However, it is not approved in the United States because in 2004, the FDA issued a public warning that the potential for cardiac arrhythmias, cardiac arrest, and sudden death significantly outweigh the benefits of the medication. Looking into these further, we were able to find a meta-analysis through PubMed published in the United European Gastroenterology Journal on the safety profile of domperidone (2018). This study concluded that the cardiovascular adverse effects of domperidone are not as significant as previously perceived, and that more studies should be conducted on the drug to highlight the risk/benefit ratio. The article did not investigate the efficacy of domperidone in the treatment of nausea against other agents used to treat nausea.
Link to the meta-analysis: https://journals.sagepub.com/doi/abs/10.1177/2050640618799153

3. Off-label use of colchicine in the treatment of recurrent aphthous ulcer (RAU) (AKA canker sores)
Colchicine is most commonly used in the treatment and prophylaxis of gout flares; however, the pharmacists were quick within our first few days at the pharmacy to question us on off-label indications of the medication. After searching online we were unable to come up with much, only a few articles highlighting its possible efficacy in pericarditis. Our pharmacist then told us that it is often prescribed off-label for the treatment of canker sores. Although the mechanism remains unclear, our literature search yielded that the immunosuppressive and anti-inflammatory properties of systemic drugs like colchicine provide relief in patients suffering from these recurrent ulcers. Evidence supporting the mechanism of colchicine shows that it may depolymerize the microtubular proteins of inflammatory cells, inhibiting a number of inflammatory processes, such as chemotaxis, mobilization, adhesiveness, and lysosomal degranulation.
A link to an article discussing an open trial using different systemic treatments in severe cases of RAU: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2666466/