Medical history

Patients with pre-existing medical conditions such as cardiovascular or respiratory disease and diabetes are at an increased risk of becoming ill and requiring medical treatment whilst abroad. These patients may also be at higher risk of developing a DVT during long-haul travel.

Patients who have had recent major surgery should be referred to their GP or consultant for assessment before flying. Patients who have suffered a myocardial infarction are advised that they should not fly for at least two weeks after the infarction. Patients who suffer from chronic gastro-intestinal conditions such as Crohn's disease or IBS should be warned that travel to developing areas may aggravate their condition.

A patient's medical history or medication may determine the suitability of certain vaccines or medication. Depression, psychoses, epilepsy, organ transplantation, HIV/Aids, psoriasis, myasthenia gravis, splenectomy, porphyria, liver or kidney disease will all require special consideration before providing travel advice. Similarly allergies or sensitivities to specific vaccines or drugs must be considered before making a recommendation.

Live vaccines should be avoided in immunosuppressed individuals and their immune response may not be sufficient to confer protection. Asplenic patients are more likely to contract more severe cases of malaria if infected.

Doses of anti-malarial chemoprophylaxis may need to be reduced in specific conditions such as kidney or liver disease, whilst their use is cautioned or contra-indicated in others; chloroquine is cautioned in patients with depression or psoriasis, whilst mefloquine is contra-indicated in patients with a range of psychiatric conditions including a history of convulsions or depression.

Medication

Medication does not only impact the option to recommend specific vaccinations or malaria chemoprophylaxis because of the potential for drug interactions, it can also pose problems for travellers for a variety of reasons including:

• Trying to obtain supplies of medication whilst abroad.
• Travel through customs with medicines such as controlled drugs, insulin needles or injections.
• Maintaining administration schedules when crossing time zones, for example warfarin.
• Ensuring cool storage of medicines such as insulin or other products requiring cold chain storage.

Female patients using the oral contraceptive should be advised that they may lose contraceptive cover if they suffer from travellers' diarrhoea or take doxycycline for malaria prophylaxis.

Some medicines, for instance chlorpromazine or doxycycline, can increase the risk of photosensitisation - an allergic-type skin reaction triggered by UV light.