Theophylline

Question 1

What is the brand name of theophylline?

Answer 1

Uniphyllin

Question 2

What is the method of action of theophyllines?

Answer 2

• Method unclear
• Inhibition of phosphodiesterase 3 (PDE3) in smooth muscle of the airways
• ↓ T-lymphocyte activity and eosinophil/neutrophil function
• Stimulates myocardium
• ↓ venous pressure in congestive heart failure = ↑ cardiac output

Question 3

What are the indications for theophyllines?

Answer 3

• Prophylaxis of bronchospasms associated with asthma, COPD and chronic bronchitis
• Treatment of bronchospasms associated with asthma, COPD and chronic bronchitis
• Left ventricular failure
• Congestive cardiac failure

Question 4

What are the contraindications for theophylline?

Answer 4

• Porphyria
• Children under 6
• High blood pressure/heart problems – take special care
• Hyperthyroidism – take special care
• Stomach ulcer – take special care
• Liver disease – take special care
• Seizures/fits/convulsions – take special care
• Viral infection/fever – take special care
• Addicted to alcohol – take special care
• Enlarged prostate gland – take special care
• Smoke – take special care

Question 5

What are the side effects of theophyllines?

Answer 5

• Nausea/vomiting
• GI upset
• Headache
• Difficulty in sleeping/agitation/anxiety/shaking
• Diarrhoea
• Difficulty passing urine/increased amounts of urine
• Cardiac arrhythmias
• Dizziness
• Seizures
• Gout
• Rash/itchy skin

Question 6

What are the interactions with theophylline?

Answer 6

• Salbutamol/ Terbutaline/Salmetarol – hypokalaemia
• Diuretics – hypokalaemia
• St John’s Wort - ↑ clearance therefore ↑ dose
• Aminoglutethimide/methotrexate/lomustine - ↑ clearance therefore ↑ dose
• Sulphipyrazone - ↑ clearance therefore ↑ dose
• Rifampicin/isoniazid - ↑ clearance therefore ↑ dose
• Ritonavir - ↑ clearance therefore ↑ dose
• Carbamazepine/phenytoin - ↑ clearance therefore ↑ dose
• Barbiturates - ↑ clearance therefore ↑ dose
• Benzodiazapines - ↓ clearance therefore ↓ dose
• High blood pressure/heart medications e.g. verapamil, propranolol etc - ↓ clearance therefore ↓ dose
• Oxpentifylline - ↓ clearance therefore ↓ dose
• Allopurinol - ↓ clearance therefore ↓ dose
• Carbimazole - ↓ clearance therefore ↓ dose
• Ciprofloxacin/clarithromycin/erythromycin/norfloxacin/ofloxacin - ↓ clearance therefore ↓ dose
• Fluconazole - ↓ clearance therefore ↓ dose
• Interferons - ↓ clearance therefore ↓ dose
• Viloxazine/fluvoxamine/lithium - ↓ clearance therefore ↓ dose
• Flu injection - ↓ clearance therefore ↓ dose
• Doxapram - ↑ CNS stimulation
• Halothane/ketamine - ↑ risk of convulsions
• Steroids
• Cimeyidine/nizatidine
• Disulfiram
• Thiabendazole
• Oral contraceptives
• Ephedrine

Question 7

What organ eliminates theophyllines?

Answer 7

Kidney