In the course of the medical assessment, information on any medication use, including complementary remedies, should be obtained. Every medication will have a clinical indication for use and fitness must be considered in terms of both the disease and its treatment. Seafarers should be asked about benefits and symptoms arising from their use of medication. If the medication is not familiar to the examining doctor then the product information leaflet or other sources of information on the medication should be reviewed for warnings about side effects.

 During the assessment any history of adverse reactions to medication should be obtained. The seafarer should be made aware of the need to inform anyone giving them medication about such reactions. Particular attention needs to be given to risks arising from the medications carried in the ship’s medicine chest and to medications used for malaria prophylaxis.

 Where a short course of medication is being taken, or where the dose of a medication is being adjusted, a case by case judgement is needed on whether, either because of the medication or the condition for which it is given, the seafarer should be made temporarily unfit or the issue of a certificate delayed until completion.

 Impairment and risks, clinical assessment and decision taking will be considered separately for each type of therapeutic effect or side-effect. Where feasible, these are grouped together. Where a particular medication is not covered, reference sources and analogy should be used to identify the likely problems.

 Many ship operators require crew members to declare any medication to the master at embarkation. It is considered to be contraband if not declared. If a seafarer is on medication it is advisable to recommend that they have the information leaflet for the medication available when they board so that decision taking on any adverse effects will be simplified.


 Medications that can impair safety critical duties


Note:  -  When the product information leaflet states that the user must not drive or work with moving machinery, this will normally be an indication of unfitness to work at sea.

- When the recommendation is that - if there are any subjective adverse effects - the user should not drive or work with moving machinery, an assessment of any effects in relation to the person’s duties is required. 

 Central nervous system depressants (Sleeping tablets, antipsychotics, some anti-anxiety and anti-depression treatments, some antihistamines).

  • Agents that increase the risk of sudden incapacitation (insulin, some of the older anti-hypertensives, medications predisposing to seizures).
  • Medications impairing vision (hyoscine, atropine). 


 Medications and increased risk to user while at sea

  • Risk of bleeding from injury or spontaneously (warfarin, asprin and some other analgesics).
  • Dangers from cessation of medication use (metabolic replacement hormones including insulin, anti-epileptics, anti-hypertensives, oral anti-diabetics).
  • Antibiotics and other anti-infection agents.
  • Anti-metabolites and cancer treatments.
  1. Medications supplied for use at individual discretion (asthma treatments, antibiotics for recurrent infections). 

Medications that require limitation of period at sea because of surveillance requirements


A wide range of agents, such as anti-diabetics, anti-hypertensives, endocrine replacements.

Note: the condition for which the medication is used, as well as the effects of the medication itself, need to be considered when making an assessment of fitness.  This should include any beneficial effects that the medication may have in reducing the impairment or risks from the underlying condition.

 Narcotic analgesics – impairment of cognition.
 - Opiates including methadone. Unfit for work at sea, other than in non-safety critical duties on vessels within harbour areas.  Case by case assessment is required for opiate antagonists used as analgesics.

 Other analgesics – few complications, risks of allergy and of gastrointestinal bleeding with regular use of some products.
 - Normally no restrictions.

 Antidepressants – impairment of cognition and drowsiness (tricyclics), impairment of cognition (SSRIs), adverse interactions with other medications and foods (MAOIs).
 - Need to be stabilised on treatment and without apparent adverse effects prior to work at sea. MAOIs not usually acceptable because of interactions.

 Benzodiazepines as sedatives, hypnotics and anxiolytics. Long acting preparations cause day-long sedation. Short acting hypnotics are without adverse effects if eight hours sleep taken, unsuitable for shorter periods between watches. Habituation may occur leading to use of increasing doses. Alcohol greatly increases impairing effects.
 - Not generally acceptable for work at sea. Only suitable if stable pattern of use, absence of subjective and objective impairment and regular monitoring of dose and effects.

 Anti psychotics and therapy for bipolar disorders. Consider in relation to underlying condition. Not normally acceptable for work at sea.

Stimulants other than caffeine. Erratic behaviour.
- Not generally acceptable.

 Antihistamines.  Used for treatment of allergies, as cough suppressants, as sedatives and as treatments for motion sickness. Many available as non-prescription medicines. All can have sedative effects, but many of those used for allergy treatment do not cross the blood brain barrier and only sedate at doses in excess of those recommended.
- Sedating antihistamines are incompatible with most safety critical duties. Regular use is not acceptable at sea. Non-sedating preparations are acceptable provided the user is aware of the dangers of exceeding the recommended dose.

 Atropine and hyoscine containing systemic medicines, including motion sickness remedies, and topical eye medications. Paralysis of accommodation in the eye leading to visual impairment occurs.
- Not acceptable if lookout duties or other safety critical visual tasks. Non absorbable hyoscine salts used in intestinal antispasmodics acceptable.

 Antihypertensives. Some of the older medications can lead to postural hypotension, impaired cardiac responses to exercise and to depression. Such effects are not generally found with newer products.
-Users may work at sea once stabilised on treatment unless it is one of the medications with the above side effects. If so, assess risks in the individual and decide on fitness based on these.

 Anticoagulants including warfarin. Increased risk of bleeding: spontaneous gastrointestinal, cerebral haemorrhage, haemarthrosis, after laceration or contused injury, intracranial bleeds after head injury. Anticoagulants are used to reduce risk after venous thrombosis, in cardiac arrhythmia and after the insertion of artificial heart valves. The use of anticoagulants at the required dose normally carries a risk of bleeding of c 2% per year, in addition to the risk of the underlying condition after such treatment. Because of the practical difficulties of dealing with poorly controlled bleeding at sea, they can cause major problems in casualty management. Regular monitoring of the level of coagulation is needed and the dose is adjusted to take account of this.
- unfit for work at sea except in sheltered coastal waters with duties that are not likely to result in injury.

 Medications increasing the risk of seizures.  Few medications increase the risk of seizures to a level where it will prevent work at sea. The anti smoking product bupropion increases the risk at doses higher than those used for smoking cessation and carries a small risk at the dose now used. It is best to start treatment at the beginning of a period of leave. It should not be used at sea if there is a history of past seizures or head injury.

 Insulin. Hypoglycaemia risk – (See diabetes)

 Oral anti diabetic medications. Hypoglycaemic risk with sulphonyl ureas – (See diabetes)

 Endocrine replacement medications. In addition to insulin therapy replacement hormones may be used for thyroid and adrenal deficiencies as well as for sex hormone replacement. The latter is not relevant to fitness to work at sea. The effects of imbalance of thyroid hormones will be slow to develop but regular surveillance will be needed. The requirements for adrenal hormones will increase if there is intercurrent infection or other stress. Inadequate doses can lead to serious illness. 
- case by case assessment of adrenal insufficiency. Not normally fit for duties other than in near coastal waters.

 Therapeutic use of corticosteroids. Short courses of inhaled steroids for asthma treatment are normally free from problems over and above those of underling condition. Continuous use or high dose oral use will increase a range of health risks.
- self administered inhaled steroids for asthma . Prolonged use or oral administration not compatible with work at sea except for non safety critical coastal duties.

  Antibiotics and other anti infection medications.  Range of side effects, commonly gastro intestinal disturbances.For short courses temporarily unfit until any impairing infection resolved.  Self administered courses for infection prophylaxis – case by case decision based on underlying conditions and antibiotic used. Prolonged use of antibiotics – case by case decision based on underlying conditions and medication used. Treatment of tuberculosis (see tuberculosis) Treatment of HIV with retrovirals (See HIV)

 Antimetabolites and anti-cancer medications. These may increase the risk of infection and a range of other complications in addition to those of the underlying condition.
- Case by case decision, Those taking these medications will usually either be unfit or require a limited certificate in terms of distance from health care or duties.

 Medications requiring regular surveillance of dose, effectiveness or side effects. In all cases the period of service at sea should not be such that surveillance is prevented. A case by case decision is needed on whether this requires a further visit to the AD or whether the seafarer can be relied on to relay any relevant information about changes to fitness to the AD.

 Medications where cessation of treatment can be dangerous. When cessation of medication use could increase the risk of a medical emergency in a seafarer it is essential that sufficient is carried for the duration of the period at sea. In addition the risks from inability to take the medication because of sea sickness or vomiting from other causes need to be considered. If they are such that severe adverse consequences can be anticipated an injectable form of the medication may need to be carried or their certificate restricted.

 Known adverse effects from a medication in an individual. Information on any known allergies or other severe side effects from medication use in an individual should be recorded and the person advised to tell anyone who treats them. Where these are potentially life threatening or the cause is a medication that could be used in an emergency they may need to be restricted or advised to wear a warning bracelet giving the details.  

 Self-administered courses of prescription medications. See 15 and 16 above. If such medications are carried then the seafarer should be advised to inform the master or responsible officer in advance of the medication and the indications for use. Self administration of emergency anti-allergy treatments such as the ‘epi-pen’ for acute allergic reactions needs to be carefully considered. If the reaction is severe and can be reasonably foreseen to be a risk at sea, for instance from a reaction to a widely used food ingredient such as peanuts, then this should limit the fitness of the seafarer as use of self-medication alone may well not be sufficiently effective. However if it is carried, for instance for use in the event of a bee sting, and the event is unlikely at sea it may be considered a useful form of personal risk reduction.



 Advice to seafarers


Be aware of any possible side effects of the medications you use and if they occur, inform the officer responsible who can obtain radiomedical or other advice on the action required.

Always have more than enough of any medication to last a trip (in case of unforeseen delays)

There will often be a requirement to notify the master of any medications brought on board and a failure to notify may be a breach of your crew agreement, or of a company drug and alcohol policy.

Ensure that you have arrangements for any required doctor visits and repeat prescriptions organised for your next leave period on board (such as antivirals[jc1] )