Author(s): W. Robert Lange, Lara DePadilla, Erin Parker, Kristin Holland

In 2020, 40.3 million people aged 12 or older in the United States (14.5% of this population) reportedly had a substance use disorder (SUD) in the past year. The prevalence of SUDs underlines the need to ensure that people who use drugs, those experiencing SUD, and those recovering from SUD have access to information that can reduce their risk of harms (e.g., overdose) and support recovery efforts. Travel, for business or pleasure, can exacerbate SUDs, cause clinical deterioration in people with a chemical dependence disorder, and impede participation in recovery support systems (e.g., 12-step groups) that help people maintain abstinence from substance use.

Travelers should be aware of policies and risks associated with substance use in nations where they are traveling. Substances that are legal in the United States, including medications used to treat SUDs, might be illegal in other countries. In addition, travelers could encounter substances in other countries that are less common in the United States, or substances that are more potent or adulterated in unexpected ways. Finally, traveling to places where substance and alcohol use regulations and policies differ from the traveler’s home (e.g., countries or states where cannabis use is legal or countries where the legal drinking age is lower than in the United States) could provide opportunities for people who otherwise do not use substances, including alcohol, to use them; such use could be associated with negative health consequences and other risky behaviors.

Most psychoactive products can complicate the physiologic adjustments associated with international travel (e.g., adaptation to different climates, elevations, time zones). Alcohol and drug use also can cause deterioration of clinical conditions during travel and can precipitate other medical problems associated with travel, including diarrheal diseases, heat-related illness, and motion sickness. Furthermore, alcohol and drugs are major contributors to unintentional injury, near-drowning, violence, arrest or detention, repatriation, and death while traveling.

Alcohol

Some people identify travel as an opportunity for increased alcohol consumption. Discuss with them that adults of legal drinking age can choose not to drink, or to drink in moderation by limiting intake to ≤2 drinks in a day for men or ≤1 drink in a day for women. Drinking less alcohol is better for health than drinking more, and individuals who do not drink should not start. People of legal drinking age who should not drink at all include those with certain medical conditions, those taking medications that can interact with alcohol, and those unable to control the amount they drink or who are recovering from alcohol use disorder. See the Dietary Guidelines for Americans for more information.

On its own, excessive alcohol use can produce undesirable effects for travelers (see Table 3-09). In addition, even small amounts of alcohol can interact with medications specifically prescribed for travel, creating adverse reactions leading to unwanted visits to unfamiliar health care providers. Alert travelers about the risks associated with drinking in other countries. In many places, alcohol concentrations in beverages exceed those found in the United States. In some countries, alcohol use is illegal in certain settings; policies can vary. Remind all travelers not to drink and drive; each country sets its own legal maximum blood alcohol concentration; in some countries, the level is below that in the United States.

Excessive Alcohol Use

Excessive alcohol use includes binge drinking, heavy drinking, and any drinking by pregnant women or people younger than the legal drinking age. Binge drinking, the most common form of excessive drinking, is defined as consuming 4 or more drinks during a single occasion (for women), and 5 or more drinks during a single occasion (for men). Although most people who binge drink do not have a severe alcohol use disorder, binge drinking is a harmful risk behavior associated with serious injuries and multiple diseases.

Excessive alcohol use, including binge drinking, is associated with short-term (e.g., alcohol poisoning, overdoses, injuries, violence) and long-term (e.g., liver disease, cancer, heart disease, hypertension) health conditions. Excessive alcohol use increases a person’s chances of engaging in risky sexual activity including unprotected sex, sex with multiple partners, or sex with a partner at risk for sexually transmitted infections (STIs). It is also associated with unintentional injuries (e.g., motor vehicle crashes, falls, burns, alcohol poisoning); violence (e.g., homicide, suicide, intimate partner violence, sexual assault); and STIs.

Tips for drinking less include setting limits, counting drinks, managing triggers (certain people, places, or activities might tempt the traveler to drink more than planned), and being around people who support moderation in or abstinence from drinking. For more details on excessive alcohol use and its effects on health, see Alcohol and Public Health.

Alcohol Use Disorder

Excessive drinking is also associated with an increased risk for alcohol use disorder, a chronic medical condition. Options and strategies for people with alcohol use disorder to avoid alcohol during travel are presented in Box 3-09; Alcoholics Anonymous provides information on meetings occurring domestically and internationally. Suggest travelers use the acronym HALT (Hungry, Angry, Lonely, Tired) to remind them of the triggers for drinking and the need to take appropriate avoidance measures.

Pharmacologic options are available to assist in treating alcohol use disorder, including acamprosate, disulfiram, and naltrexone. Advise travelers taking disulfiram to avoid “alcohol-free” beers because these products can contain ≤0.5% alcohol, enough to produce a reaction. Moreover, it is inadvisable to initiate first-time pharmacologic intervention at the onset of an international trip.

Cannabis

The cannabis plant contains more than 100 compounds (or cannabinoids). Cannabis (marijuana, weed, pot, dope) refers to the dried flowers, leaves, stems, and seeds of the cannabis plant, as well as concentrates, edibles, extracts, tinctures, vape cartridges, and other products that contain Δ-9-tetrahydrocannabinol, the main psychoactive ingredient of the plant. Because cannabinoid use policies vary from country to country, travelers should review the policies and regulations around transport, possession, and use of cannabis or cannabinoids in the countries to which they are traveling and passing through. In many countries, possession and use of cannabis can result in severe criminal penalties, including imprisonment.

Cannabis has been legalized in some US states for medical or nonmedical adult use, and although its use and possession at some airports might be allowed, cannabis remains categorized as a Schedule I substance in the United States and is illegal at the federal level. Cruise lines follow federal law; federal scheduling of cannabis as a Schedule I substance also prohibits use and possession on cruise ships.

Opioids

According to the National Survey on Drug Use and Health (), in 2020, 9.5 million people aged >12 years reported misusing prescription opioids or using heroin within the past 12 months, and 2.7 million reported having an opioid use disorder (OUD). OUD is not uncommon in the United States, and travel medicine providers likely will encounter patients experiencing, or in recovery for, this condition. Preparing travelers with OUD to travel internationally requires additional planning.

Illicit opioid use and misuse of prescription opioids are factors that increase risk for overdose. Evidence-based strategies for reducing the risk for overdose associated with illicit opioid use include use of fentanyl test strips (FTS) and access to naloxone. FTS are used to determine whether fentanyl has been mixed with drugs; naloxone can reverse an overdose from opioids, including fentanyl, heroin, and prescription opioid medications.

Medications for Treating Opioid Use Disorder

Medications are available to effectively prevent overdose, treat OUD, and sustain recovery; these medications might be restricted or prohibited in other countries, however. Examples of medications used to treat OUD include buprenorphine and methadone, which act as opioid agonists. These medications reduce cravings and withdrawal symptoms and block the effects of other opioids (e.g., heroin). The opioid antagonist naltrexone works by blocking the effects of opioids.

The Transportation Security Administration (TSA), US Department of State, and US Centers for Disease Control and Prevention (CDC) provide guidance for traveling with prescription medications, including medications used to treat substance use disorders. Travelers should check with the US embassy located in the country they plan to visit or travel through to make certain their medications are allowed in that country and determine whether they need any documentation to bring medications. The International Narcotics Control Board provides information on country regulations for travelers carrying medications containing controlled substances.

Travelers should carry all medications in their original labeled container with a copy of the prescription printed on the container and a statement from the medical director of the clinic or prescribing physician on letterhead detailing the care being provided. The name listed on prescriptions, medication bottles, and letters from health care providers should match the name on the traveler’s passport. Although medications can be packed in carry-on or checked baggage, traveling with prescriptions in carry-on luggage can help to ensure ready access to medications in an emergency or if checked luggage is lost.

Methadone

In the United States, methadone treatment programs are strictly regulated by the federal government, and methadone treatment for OUD can only be dispensed by federally certified opioid treatment programs (OTPs); regulations include prerequisites to be eligible for take-home medication. Most methadone treatment programs dispense the medication daily in person, and a patient must complete continuous treatment in an OTP for >12 months before being permitted to take home >1 week’s supply of methadone. A maximum of 1 month’s (31 days) supply of methadone can be provided to patients who have completed 2 years of continuous treatment.

Recovery Support Services

Encourage patients with OUD to review information about recovery support services in other countries, such as information provided on the Narcotics Anonymous website. In addition, global advocacy and support groups are available for people taking methadone and other treatments for OUD. For instance, the German organization INDRO e.V. operates the Coordinating and Information Resource Center for International Travel by Patients Receiving Methadone and other Substitution Treatments for Opiate Addiction and publishes International Travel Regulations for Patients Participating in Drug Substitution Treatment and the Methadone Worldwide Travel Guide.

Substance Use Disorder Treatment

A subtype of “medical tourism” (see Sec. 6, Ch. 4, Medical Tourism) involves travel to another country for SUD treatment and rehabilitation care (“rehab tourism”). Box 3-10 lists some pros and cons of tourism for substance use disorder treatment. Travelers exploring this option might be seeking a greater range of treatment options at less expense than what is available domestically.

Before a traveler selects an international program for SUD treatment, encourage them to review information that can help them better understand proposed treatments. Evidence-based guidance is available from the Substance Abuse and Mental Health Services Administration (Medication Assisted Treatment, Co-Occurring Disorders and Other Health Conditions, Treatment of Stimulant Use Disorders) and CDC (Evidence-Based Strategies).