Factors contributing to variation in clearance of theophylline

Increased clearance

• Enzyme induction by drugs: rifampicin, ethanol, phenobarbitone
• Smoking: tobacco, marijauna
• High-protein, low-carbohydrate diet
• Childhood

Decreased clearance

• Enzyme inhibition by drugs: cimetidine, erythromycin, allopurinol, zafirlukast, ciprofloxacin
• High carbohydrate diet
• Congestive heart failure
• Liver disease
• Pneumonia
• Viral infection and vaccination
• Old age 

Look for mechanism of action of theophylline. 

Theophylline: multiple mechanism of action

• Non selective phosphodiesterase inhibition: bronchodilation primarily attributed to increase in cAMP* 
• Adenosine receptor blockade: additional bronchodilatory effect 
• Promotes apoptosis of neutrophils and eosinophils
• Activation of histone deacetylase (HDAC):

* Increase in cAMP can mediate other effects:

• Reduced expression of proinflammatory genes
• Increase in interleukin 10; a antiinflammatory cytokine levels

Respiratory system classification

Anti-tussives
Drugs for bronchial asthma/COPD

Drugs for bronchial asthma/COPD classification

1) Bronchodilators

a) Methylxanthines (phosphodiesterase inhibitors)

Theophylline

Aminophylline

Choline theophyllinate

Hydroxyethyl theophylline

Doxofylline

b) Sympathomimetics:

i) Non selective

Adrenaline

Ephedrine

Isoprenaline

ii) β₂ selective

Salbutamol

Levosalbutamol

Terbutaline

Bambuterol

Salmeterol

Formoterol

Fenoterol

Rimeterol

Indacaterol

c) Anticholinergics

Atropine methonitrate

Ipratropium bromide

Tiotropium bromide

2) Anti-inflammatory Drugs

a) Leukotriene antagonists

Montelukast

Zafirlukast

Iralukast

b) Leukotriene synthesis inhibitor

Zileuton

c) Mast cell stabilizers

Sodium cromoglycate

Nedocromil

Ketotifen

d) Corticosteriods

i) Systemic

Hydrocortisone

Prednisolone

ii) Inhalational

Fluticasone propionate

Flunisolide

Beclomethasone dipropionate

Budesonide

3) Anti IgE Antibody

Omalizumab 

4) IL 13 antagonist

Lebrikizumab

5) Thromboxane receptor antagonist

Seratrodast

6) PDE IV inhibitors

Cilomilast

Roflumilast

Anti-tussives classification

1) Peripheral acting

a) Pharyngeal demulcents and local sialogogues

Lozenges

Linctuses containing syrups

Menthol

Glycerine

Liquorice

b) Expectorants (Mucokinetic agents)

i) Directly acting

Citrates and Acetates of sod and Pot

Potassium iodide

Balsum of Tolu

Vasicine (alkaloid in Vasaka)

Terpin hydrate

Guaiphenesin

ii) Reflexively acting

Ammonium chloride

Potassium iodide

iii) Mucolytics

Acetyl cysteine

Mecysteine

Carbocisteine

Bromhexine

Ambroxol

Dornase alfa inhalation

2) Central acting

a) Opioids

Codeine

Pholcodeine

Ethylmorphine

Morphine

Methadone

b) Non-opioids

Noscapine

Dextromethorphan

Oxeladin

Chlophedianol

Carmiphene

Pipezethate

c) Antihistaminic

Chlorpheniramine

Diphenhydramine

Chlorcyclizine

Promethazine

d) Pulmonary receptor desensitizer

Prenoxdiazine