Pharm Other BD (Side Door) Flashcards
-Methylxanthines (Side Door)
-Referred to simply as xanthines, xanthine derivatives, or as methylxanthines
-These are phosphodiesterase inhibitors which indirectly increase the amount of cyclic AMP within smooth muscle causing bronchodilation
-Xanthines used therapeutically include:
-Caffeine
found in the seeds of a coffee plant
-Xanthines used therapeutically include:
-Theophylline
found in tea leaves (mostly oral medications Theo-Dur
-Clinical uses of theophylline include the management of:
-Asthma
-Sustained release theophylline is indicated as an alternative for maintenance therapy of mild, persistent asthma and higher in patients older than 5 years of age
-Listed as an alternative for patients older than 5 years of age in combination with ICS -Side effects and narrow therapeutic index may make it a poor choice vs. others agents
-Clinical uses of theophylline include the management of:
-Chronic obstructive pulmonary disease(COPD)
-The global initiative for chronic obstructive lung disease (gold) states that inhaled bronchodilators are preferred when available
-Theophylline: recommended by GOLD as alternative to B2 agonist and anticholinergics -Not used in acute exacerbation
-Apnea of prematurity in neonates
-Methylxanthines are considered the first line agents of choice as treatment
-Theophylline was most extensively used in the past, but caffeine citrate may be a better choice (as it is safer, higher therapeutic index)
All xanthine’s have the following effects
-CNS stimulation
-Skeletal muscle stimulation -Cardiac stimulation -Bronchodilaton -Pulmonary vasodilation -Smooth muscle relaxation -Theophylline is generally classified as a bronchodilator -Peripheral and coronary vasodilation -Diuresis -Cerebral vasoconstriction -Used in headache remedies
-The basic effects of xanthine’s on the lung are:
-Decreased airway resistance (result of Bronchodilation
-Decreased pulmonary vascular resistance (result of pulmonary vasodilation) -Stimulated ventilation (CNS)
optimum serum theophylline level
-There is variability in individual metabolic rates among patients, which makes it difficult to control therapeutic dosages
-To optimum serum theophylline level for maximal bronchodilation in adults is between 10n and 20 mcg/ml. And 5-10 mcg/mL in neonates and children
-Blood levels are important to monitor in patients receiving methylxanthine drugs as toxicity is serious!
-Side effects or lack of therapeutic effects are associated with the following serum levels:
-Theophylline
-< 5 micrograms/ ml- no effects seen
-10-20 micrograms/ ml therapeutic range - > 20 micrograms/ ml Nausea - 40-45 micrograms/ ml seizures -Asthma management - 5 to 15 ug/ ML ug means micrograms -COPD management -5 to 10 ug/ ml
-Theophylline Theraputic index
-It is stressed that the ranges given for toxic effects are approximate
-It is possible for an individual to bypass the nausea phase of toxicity and begin having seizures immediately -In practice and initial loading dose is given following by a maintenance dosage adjusted to obtain therapeutic plasma levels
aminophylline
-It should be noted that aminophylline is a double salt of theophylline compound to give aqueous solubility
-This enables one to give the drug IV
-Adverse Reaction with Theophylline
-Central nervous system
-Headaches
-Anxiety -Restlessness -Insomnia -Tremor Convulsions
-Adverse Reaction with Theophylline
-Gastrointestinal
-Nasua
-Vomiting -Anorexia -Abdominal pain -Diarrhea -Gastroesophageal reflux
-Adverse Reaction with Theophylline
-Respiratory
-Tachypnea