Travelling with medicines can pose significant problems for patients. Changing time zones and the regulations concerning carrying liquids or sterile equipment on planes can be confusing, even for frequent flyers.

Patients might also be concerned about carrying certain medicines across borders, or they may face problems obtaining the medicine they need when they arrive at their destination.

Pharmacists therefore have an important role to play in helping their patients prepare for trips abroad, by enabling them to travel with their essential medication.

Time zone changes 

During long-haul flights there is the potential for medication regimes to be disrupted, due to changing time zones. However, it is important to remember that the range of conditions and medicines that may be affected by long-distance travel is relatively small. For example, there have been reports that patients on insulin therapy have found it difficult to maintain their glycaemic control during such trips.

A number of solutions to this have been recommended. There are regimes that have been devised to alter insulin doses when travelling across more than six time zones.

Alternatively, travellers may be advised by their diabetic clinic to alter the dose of insulin by 2-4% for every time zone travelled. You should also advise patients who are flying with insulin to ensure they carry all their vials in their cabin luggage, due to the variable temperatures in the hold.

When travelling across a number of time zones on long-haul flights, there are theoretical risks with medication which has both a short half-life and a narrow therapeutic index, for example antiretrovirals and low-dose contraceptives. This is because patients may have problems readjusting their wake and sleep cycles in transit and when their journey ends.

However, there is no evidence to indicate this risk is clinically significant. For patients on warfarin therapy, the change in routine, lifestyle and diet during a holiday may affect their INR levels, so you should advise them to use self-monitoring testing kits while they are away. If they are travelling across more than six times zones, then they may have to adjust their dose. 

Getting through airport security

When it comes to medicines, you should advise patients that UK border security  allows patients to carry more than the standard liquid restriction of 100 millilitres in their hand luggage, as well as syringes, although they will have to show a copy of their prescription.

However, once their travels have begun they may find thatother countries have different regulations, so they should always ensure they have adequate proof the medicine is required.

In some countries it may be prohibited to import a range of medicines , which could be confiscated and may lead to the patient being prosecuted.

In general, these restrictions are based on the potential of the drug for abuse. The major drug groups affected are those generally classed as psychotropics or narcotics. Other medicines that may be subject to restrictions include anabolic steroids, which can be abused by athletes.

Every country has its own rules around importing medicines . The only international attempt to standardise these is by the International Narcotics Control Board (INCB), and relates specifically to narcotics and psychotropics. Most countries impose more stringent regulations than those advised by the INCB. The United Arab Emirates has the largest list of restricted items, followed by Japan, which also has complex documentation requirements.

Buying medicines abroad

You should warn travellers about the risks of obtaining medicines whilst overseas. In some cases their medication may not be available, or not easy to identify due to language differences. Communicating what is needed and understanding instructions in another language may also be difficult.

Currently, many parts of the world have substandard medicines, including counterfeit drugs and medicines made using poor manufacturing and quality control processes.

It’s difficult to know the exact size of the problem, but it’s estimated that up to 25% of medicines in Africa and parts of Asia might be defined by the World Health Organisation as “spurious, falsely-labelled, falsified or counterfeit”.

You should therefore advise patients to purchase any medicine they might need before they travel and only use reliable registered pharmacies once abroad. A local consulate may be able to supply a list of suitable ones.

Common travel remedies 

Don’t forget to remind patients that they should carry over-the-counter medicines for common travel-related conditions, such as rehydration products for diarrhoea, simple analgesics, oral antihistamines for bites, and topical antifungals if they are travelling to hot, humid climates. Travellers to high altitude areas may need to take prophylactic acetazolamide for acute mountain sickness, and malaria prophylaxis if travelling to malaria-endemic areas.

Carrying prescription medicines, particularly antibiotics, as ‘standby’ treatments is a contentious issue. However, the use of ciprofloxacin or azithromycin to treat traveller’s diarrhoea is well-established.

Some long-term travellers may be prescribed a standby broad-spectrum antibiotic if going to a country with a high level of certain infectious diseases and poor quality medicines, or standby malaria treatments if going to isolated areas.

Alternatively, patients with allergies that cause anaphylaxis might need to be supplied with an adrenaline autoinjector, such as an EpiPen.

Professor Larry Goodyer is head of De Montfort University's school of pharmacy

Listen to C+D's travel health podcast, covering the Zika virus, malaria and mosquito bites: