the combination therapy contemplated by this invention comprises administering a pde4 inhibitor with a long - acting beta adrenergic bronchodilator to prevent onset of a pulmonary disease event or to treat an existing condition . the compounds may be administered together in a single dosage form . or they may be administered in different dosage forms . they may be administered at the same time . or they may be administered either close in time or remotely , such as where one drug is administered in the morning and the second drug is administered in the evening . the combination may be used prophylactically or after the onset of symptoms has occurred . in some instances the combination ( s ) may be used to prevent the progression of a pulmonary disease or to arrest the decline of a function such as lung function . the pde4 inhibitor useful in this invention may be any compound that is known to inhibit the pde4 enzyme or which is discovered to act in as pde4 inhibitor , and which are only pde4 inhibitors , not compounds which inhibit other members of the pde family as well as pde4 . generally it is preferred to use a pde4 antagonists which has an ic 50 ratio of about 0 . 1 or greater as regards the ic 50 for the pde iv catalytic form which binds rolipram with a high affinity divided by the ic 50 for the form which binds rolipram with a low affinity . pde inhibitors used in treating inflammation and as bronchodilators , drugs like theophylline and pentoxyfyllin , inhibit pde isozymes indiscriminently in all tissues . these compounds exhibit side effects , apparently because they non - selectively inhibit all 5 pde isozyme classes in all tissues . the targeted disease state may be effectively treated by such compounds , but unwanted secondary effects may be exhibited which , if they could be avoided or minimized , would increase the overall therapeutic effect of this approach to treating certain disease states . for example , clinical studies with the selective pde 4 inhibitor rolipram , which was being developed as an antidepressant , indicate it has psychotropic activity and produces gastrointestinal effects , e . g ., pyrosis , nausea and emesis . it turns out that there are at least two binding forms on human monocyte recombinant pde 4 ( hpde 4 ) at which inhibitors bind . one explanation for these observations is that hpde 4exists in two distinct forms . one binds the likes of rolipram and denbufylline with a high affinity while the other binds these compounds with a low affinity . the preferred pde4 inhibitors of for use in this invention will be those compounds which have a salutary therapeutic ratio , i . e ., compounds which preferentially inhibit camp catalytic activity where the enzyme is in the form that binds rolipram with a low affinity , thereby reducing the side effects which apparently are linked to inhibiting the form which binds rolipram with a high affinity . another way to state this is that the preferred compounds will have an ic 50 ratio of about 0 . 1 or greater as regards the ic 50 for the pde 4catalytic form which binds rolipram with a high affinity divided by the ic 50 for the form which binds rolipram with a low affinity . examples of such compounds are : most preferred are those pde4 inhibitors which have an ic 50 ratio of greater than 0 . 5 , and particularly those compounds having a ratio of greater than 1 . 0 . preferred compounds are trequinsin , dipyridamole , and papaverine . compounds such as cis -[ cyano - 4 -( 3 - cyclopentyloxy - 4 - methoxyphenyl ) cyclohexan - 1 - carboxylate ], 2 - carbomethoxy - 4 - cyano - 4 -( 3cyclopropylmethoxy - 4 - diflouromethoxyphenyl ) cyclohexan - 1 - one , and cis -[ 4 - cyano - 4 -( 3 - cyclopropylmethoxy - 4 - difluoromethoxyphenyl ) cyclohexan - 1 - ol ] are examples of structures which bind preferentially to the low affinity binding site and which have an ic 50 ratio of 0 . 1 or greater . reference is made to co - pending u . s . application ser . no . 08 / 456 , 274 filed may 31 , 1995 and its parent a pct application published jan . 05 , 1995 as w ) 95 / 00139 for a methods and techniques which can be used to identify compound which have a high / low ic 50 ratio of 0 . 1 or greater as referred to in the proceeding paragraph . this co - pending application , u . s . ser . no . 08 / 456 , 274 is incorporated herein by reference as if set out in full herein . the several specific compounds set out above which do not have a generic or trade name can be made by the processed described in co - pending u . s . patent applications u . s . ser . no . 862 , 083 filed oct . 30 , 1992 ; u . s . ser . no . 862 , 111 filed oct . 30 , 1992 ; u . s . ser . no . 862 , 030 filed oct . 30 , 1992 ; and u . s . ser . no . 862 , 114 filed oct . 30 , 1992 or their progeny or u . s . patent ( s ) claiming priority from one or more of these applications . each of these applications or related patents is incorporated herein by preference in full as if se t out in this document . the beta adrenergic bronchodilator , β 2 - adreneric agonists really , used in this invention will be a long - acting compound . any compound of this type can be used in this combination therapy approach . by long - lasting it is meant that the drug will have an affect on the bronchi that lasts around 6 hours or more , up to 12 hours in some instances . to illustrate , certain resorcinols such as metaproterenol , terbutaline , and fenoterol can be combined with a pde4 inhibitor in the practice of this invention . further examples of useful beta adrenergic bronchodilators is the likes of two structurally related compounds , albuterol { racemic (∝ 1 -[( t - butylamino ) methyl ]- 4 - hydroxy - m - xylene -∝,∝′- diol )} and formoterol {( r *, r *)-(±)- n -[ 2 - hydroxy - 5 -[ 1 - hydroxy - 2 -[[ 2 -( 4 - methoxyphenyl )- 1 - methylethyl ] ethyl ] phenyl ] formamide }. metaproterenol is the subject of u . s . pat . no . 3 , 341 , 594 and is commercially available under the trade names of alotec , alupent , metaprel or novasmasol . terbutaline is described in u . s . pat . no . 3 , 938 , 838 and is available commercially as brethine from novartis . the preparation of fenoterol is described in u . s . pat . no . 4 , 341 , 593 . it is sold under several trade names , including airum , berotec , dosberotec and partusisten . albuterol is sold under the trademark proventil ® by schering corporation . formoterol is described in u . s . pat . no . 3 , 994 , 974 and is available commercially under the names atock and foradil . these drugs , the beta agonists , are usually administered as an oral or nasal spray or aerosol , or as an inhaled powder . usually these drugs are not administered systemically or by injection . the pde4 inhibitors can be administered orally or by inhalation ( orally or internasally ). this invention contemplates either co - administering both drugs in one delivery form such as an inhaler , that is putting both drugs in the same inhaler . alternatively one can put the pde4 inhibitor into pills and package them with an inhaler that contains the beta agonist . formulations are within the skill of the art . it is contemplated that both active agents would be administered at the same time , or very close in time . alternatively , one drug could be taken in the morning and one later in the day . or in another scenario , one drug could be taken twice daily and the other once daily , either at the same time as one of the twice - a - day dosing occurred , or separately . preferably both drugs would be taken together at the same time . the foregoing statements and examples are intended to illustrate the invention , not to limit it . reference is made to the claims for what is reserved to the inventors hereunder .
this invention relates to treating pulmonary diseases such as chronic obstructive pulmonary disease or asthma by administering a phosphodiesterase - 4 inhibitor with a beta - adrenergic bronchodilator .