Antiasthmatics and anticoagulants, and their impact on driving

Drugs used in asthmatic patients

• Beta-adrenergic agonists: Isotharine, terbutaline, salbutamol, orciprenaline, fenoterol, salmeterol, and isoprenaline by inhalation have faster effects and better therapeutic rates.They can cause paradoxical bronchospasm, light hand tremor, headache, hypotension, tachycardia, palpitations, and possibility of arrhythmia including atrial fibrillation and muscle cramps. Sleep and behavior disturbances have been seen, including agitation, hyperactivity, and restlessness. Formoterol fumerate can cause tremor and agitation that interferes with driving.
• Methylxanthines: Theophylline and its derivatives can be administered by oral route. Dose adjustment is sometimes not easy, because theophylline clearance varies a great deal and liver insufficiency, cardiac decompensation, cor pulmonale, and fever increase with age. Many substances such as tobacco and drugs including phenobarbital and diphenylhydantoin also have an influence reducing the half-life of theophylline. Erythromycin, allopurinol, cimetidine and propanolol have the contrary action. Theophylline can cause side effects, particularly with plasma levels higher than 20 mcg/mL:
  • Gastrointestinal such as nausea, vomiting, diarrhea, epigastric pain, intestinal bleeding, and hematemesis.
  • Central nervous system stimulation, with irritability, nervousness, headache, insomnia, muscle spasms, reflex hyperexcitement and sometimes generalize tonoclonic seizures.
  • Cardiovascular with palpitations, tachycardia, extrasystoles or ventricular arrhythmia, peripheral vasodilatation and hypotension.
• In order to prevent the symptoms, serum levels of the substance should be measured to thus make the dose adjustment.
• Glucocorticoids: Budesonide and beclomethasone are well tolerated in inhalation at the standard doses, and their adverse events are not significant, including irritative cough or dysphonia. Other corticoids used by oral route in serious asthma and always at the lowest dose needed are prednisone and methylprednisolone. In long-term treatments they can cause Cushing syndrome, hyperglycemia, osteoporosis, hypertension, edema, psychotic states, muscle atrophy, cataracts, glaucoma, peptic ulcer, digestive bleeding, aseptic bone necrosis, thrombosis, etc.
• Sodium cromoglycate: It is not a bronchodilator, but is useful as long-term treatment or prevention, in inhaler or vaporizer. It can cause sneezings, burning or irritation, and less frequently nausea, headache, bronchospasm and epistaxis.
• Anticholinergics: Atropine and related compounds such as ipratropium are applied in aerosol. They can cause dry mouth, throat irritation, cough or allergic reactions and paradoxical bronchospasm. In patients with narrow angle glaucoma intraocular pressure elevation can occur if the substance enters the eye. The asthmatic patient used to handling his drugs can abuse of the dosage in quantity or frequency, hoping to obtain a faster benefit, but does not know the side effects of the drugs.
• Oral anticoagulants: Vitamin K antagonists, such as acenocoumarol, are the oral treatment of choice, but require an accurate, individualized control of the dosage. Multiple drugs have pharmacological interactions with oral anticoagulants. Their effect are enhanced by chlorpromazine, sulfonamides, chloramphenicol, allopurinol, tricyclic antidepressants, softening, salicylates, thyroxin, androgens, antiarrhythmic such as amiodarone and quinidine, clofibrate, H2 antagonists, glucagon, disulfiram and some antibiotics including erythromycin, tetracycline, neomycin and imidazole derivatives. Their effects are reduced by vitamin K, barbiturates, rifampicin, cholestyramine, thiazides, carbamazepine, griseofulvin, and some oral contraceptives. The administration of anticoagulants is not recommended with substances that modify hemostasis, such as acetyl salicylic acid, phenylbutazone and pyrazolone derivatives. Patients treated with oral anticoagulants are susceptible to bleeding complications, sometimes serious. Trying to prevent this complication, the anticoagulant treatment is adjusted individually in terms of dosage and duration.

Recommendation on drugs used in asthmatic patients

• Physicians should warn the patient of the side effects of antiasthmatic drugs and their interference with driving.
• Although respiratorily the patient feels well to drive, the drug-induced symptoms will be often disabling for driving the car safely. The patient should be warned about this.

Recommendation on oral anticoagulants

• The patients treated with oral anticoagulants are susceptible to bleeding complications, sometimes serious.
• These patients cannot take acetyl salicylic acid, or drugs that modify the anticoagulant effect.
• Every new drug can destabilize the patient on anticoagulation, and, accordingly, when a drug is added or removed from the therapeutic regimen, this risk should be notified, advising against driving transiently if required.
• We should warn the patient not to take over-the-counter drugs, or those indicated by a physician who does not know that the patient is receiving anticoagulation.
• It is advisable that the patients treated on an outpatient basis takes in the car a control sheet specifying the coagulation in case they are injured.
• The patient on anticoagulation should know the greatest risk of suffering bleeding and be responsible for this trying to develop a safe driving.
• Therefore, being more cautious will reduce the possibility of blows than, though minor, could have dramatic consequences in them.
• The hematologist will report on the adequate control of the patient who permits him to drive.