Tubercle, Lond., (I958), 39, 2oi

Evaluation of 'Dipasic' in Treating Chronic Pulmonary Tuberculosis

By H O W A R D W I L L I A M S and J A N P R O K O P O W I C Z

from the Islington Chest Clinic, London

Several reports on 'dipasic', the p-amino salicylic salt of isoniazid, have appeared in the literature since I953. The first British report (Clegg, i955) suggested its use was jugtified in case of pulmonary tuberculosis on the clinical and bacteriological results. Many writers (Wilder Smith and Wiederkehr, i 953; Krug, 1954; Freudenthal, x 955; Klose and Mertens, I956 ) reported good clinical, x-ray and bacteriological improve- ment of patients treated with it. One of the earliest papers (Brodhage, 1954) con- cluded that 'dipasic' was therapeutically effective even in patients with strains of bacilli resistant to PAS and isoniazid. On the other hand, B6hlke and Schoeps (I956), reported that only 3 out of 37 patients producing isoniazid resistant "organisms improved, compared with I3 out of 2I in whom the strains were fully, sensitive to isoniazid; and Cuthbert and others (i958) found no striking improvement in I7 patients with isoniazid resistant strains. Recent papers, e.g. Walker and others (1957) , suggest that the drug acts only by virtue of its isoniazid content. I f this is so, 'dipasic' would be expected to have a therapeutic effect if the infecting bacilli .are sensitive to isoniazid. In estimating its mode of action in a mixed group of patients, therefore, they must be divided into those with isoniazid sensitive cultures and those with resistant cultures before treatment.

The drug was first used at the Islington Chest Clinic at the end of I955. We were encouraged to try its effect by previous favourable reports, but no planned trial was contemplated. Our results, even with the deficiencies inherent in such retrospective studies, may help in assessing its value.

M e t h o d s 'Dipa~ic' was given to over 9 ° out-patients, of whom 55 had a positive sputum before treatment. Sputum sensitivity tests on pre-treatment cultures were available in only 4~ of these. SLxteen of the 42 had cultures resistant to isoniazid and the remaining 06 had sensitive cultures. This paper will mainly concern the 42 patients with available sputum sensitivity tests.

The drug was given for periods varying from two to eleven months. The duration of disease from diagnosis varied from one to twenty years. Twenty-six of the 42 were over 5 ° years of age. Twenty-nine were up and a b o u t a l l day and in good general condition, 7 seven were semi-invalid and 6 bed-ridden. All except 3 had x-rays showing bilateral disease and 34 had obvious cavitation in one or both lungs. Because of age, extent and nature of disease most of the patients were considered unsuitable for surgical treatment although two were later treated by pneumonectomy and one by thoracoplasty. Some had. previously refused surgical treatment. All had received PAS and isoniazid and all except 2 had received streptomycin. The three drugs had been given alone or in various combinations~ many having had several courses of combined chemotherapy.

0 0 9 T U B E R O L E

Sensitivity Tests Standard methods of testing were employed. The specimen was first examined by direct smear. I t was then treated by Petroff 's method as modified by Mackie and McCar tney 0953) After incubation and centrifuging, the sediment was inoculated on to L6wenstein-Jensen medium and incubated for six weeks, the cultures being examined at weekly intervals. When the culture was sufficiently grown it was suspended by adding i -2 ml. of sterile saline. The same number of drops of the suspension were added to L6wenstein-Jensen slopes containing varying concentrations of the drugs incorporated in the medium before it set. F o r isoniazid, the concentra- tions used were o.2, i, 5, to and 5 ° t~g. per ml.; for 'dipaslc' o'2, I, 5 and 5 ° vg. per ml. ; and for PAS 2, IO and IOO/~g. per ml. A control culture containing no drug was also inoculated. The reference strain H37Rv was put up with each batch of tests. T h e definitions of the standards of resistance used are given in the footnote to Table I.

Dosage Thirty-seven patients received 6oo rag. of 'dipasie' daily in divided doses, 3 received 4oo mg. a day and 2 patients Were reduced from 6oo to 4oo rag. during treatment.

T A B L E I . -- S P U T U M S E N S I T I V I T Y R E S U L T S B E F O R E A N D A F T E R D I P A S l G T R E A T M E N T

Patient Before dipaslc After dibasic Amount and duration of dipasic

Isoniazid PAS Isoniazid PAS Dipasic Grw.ns Days

I o

3 4 5 6 7 8 9

IO IX 12

z3 14 x5

16 x7 x8 19 2 0 21

2 2

23 24 25 26 27

S S S S S S S S S S S S S S S S S S S S S S S S S S S PR s R

PR S PR S PR S PR S PR S P R S P R S R S R S R R R R R R

R S S R S • P R P R S P R R S - - R S P R

~ S S S S S S - - P R S - - - - - - S R PR - - P R S S PR S S P R R S PR PR --

P R R P R P R S PR P R S S P R S S S S - - R S R P R P R P R R P R P R S P R R PR. P R R S P R P R S P R

87.6 146 55"2 92 7 t .4 t l 9 66.6 l l i 72-0 I2o 88-2 x47 59"4 99 50"4 8a 85"8 t45 33 .o 73 36"o 6o 64"2 I57 36.o 6o

io8.6 181 75-6 i26

76"8 t28 87"0 I45 83"4 t38 88.8 t46

IO: '4 169 8o '4 t34 66.6 tx i

195"o 325 :or -6 t88 67-2 1:2 49.2 "82 88-8 4 6

S=Sens i t ive . P R = P a r t i a l l y resistant. R = R e s i s t a n t . Isonlazld-stralns were considered sensitive if there was no .g rowth in media exceeding o'2 ~ug.

isoniazid per hal., part ial ly resistant if there was no growth in media exceeding 5 tag. per ml., and resistant if there was growth on to tag. per ml. , and over. ' D i p a s l c ' - a s for isoniazid.

P A S - strains were considered sensitive if there was no growth in med ia exceeding 2 tag. per ml. , i~artially resistant if no growth in media exceeding I O tag. per ml., and resistant i f there was growth on med ia above to/~g, per ml.

~DIPASIC' 20 3

Results

The 16 patients with initially isoniazid resistant cultures are first considered and their clinical and radiographic response recorded. The clinical and radiographic changes in the 26 with initially isoniazid sensitive cultures are not here recorded. The bacteriological findings of both groups are considered together.

PATIENTS XVITtt INITIALLY ISONIAZID RESISTANT CULTURES

Subjecth'e effects Seven of the I6 patients with cultures resistant to isoniazid before treatment reported less cough and sputum. The sputum assessments were based on the patients' estimates during interviews and not on measurements by clinic staff. Seven reported an improvement of appetite and I a loss of appetite. Eight experienced a greater sense of well being and i felt worse.

IVeight gahz O f the i6 patients, 5 recorded weight gains of I I , 4, 5, 7 and 14 lb ; 2 patients lost 4 lb and 14 lb respectively. The remaining 9 showed no appreciable weight change.

Radiographic changes Four of the 16 patients showed x-ray improvement after 'dipasic' with retrogression of mottling and reduction of cavity size. In I of the 4, cavity closure was observed. On the other trend I of the I6 patients showed x-ray deterioration with efllargement of cavities. The other patients' x-rays showed no change.

Bacteriological results One of the I6 patients with cultures resistant to isoniazid before treatment has been sputum negative since, while another was sputum negative for seven months before a further positive result was recorded. The remaining t 4 patients were still sputum positive at the end of treatment.

PATIENTS XVITI[ ISONIAZID SENSITIVE--OR ISONIAZID RESISTANT CULTURES

Sensitivity tests Although 42 patients had sputum sensitivity results available before treatment only 27 had results available both before and after treatment.

PoSitive sputum cultures were obtained from 19 of the 27 patients within the three months preceding 'dipaslc' and from 2o within three months of completing treatment. Tile remaining cultures were obtained outside this period. Thus sensitivity results were not ahvays available immediately before and after 'dipasic'. In some of our patients 'dipasic' therapy was preceded or followed by combined chemotherapy with PAS and isoniazid. I t is possible that a few of our sensitivity results were affected by tiffs.

Tim results from the I5 patients with pre-treatment cultures fully sensitive to isoniazid are shown in the first part of Table I. After t reatment the strains from I I patients had become resistant to isoniazid, 6 partially and 5 fully. Two remained fitlly sensitive. There were no available sens{tivity results for the remaining ~. Partial resistance to 'dipasic' was present in the cultures of 3 patients, 7 were fully sensitive, and in 4 post-treatment results were not av.ailable. No strains were fully resistant to 'dipasic'.

O f the I2 patients whose cultures were initially resistant t o isoniazid, Ix still had cultures resistant to isoniazid in varying degrees after treatment, and one

2o4 TUBERCLE

had an isoniazid sensitive culture. Eight patients of this group had strains partially resistant to 'dipasic' after treatment, the strains were sensitive in 2 and in the remain- ing 2 no results were available.

The PAS sensitivities altered little in the whole group of 27 patients.

~"OXIC EFFECTS Of the total 93 patients who received 'dipasic' only6 attributed symptoms to the drug, namely headaches, depression, soreness of mouth, dyspepsia, indigestion and vomiting. The drug was stopped in x patient after fourteen days because of the vomiting. All 6 had previously had PAS and isoniazid and only I had complained of severe indigestion with PAS. The remaining 87 patients did not complain of any symptoms. There were no drug rashes. Thirty-seven of the 93 had reacted to other antituberculous chemotherapy on previous occasions, 18 having complained of alimentary symptoms, headaches 6r rashes with PAS and ~ having had rashes with isoniazid.

D i s c u s s i o n "~;alker and others (x957) produced the most critical assessment of 'dipasic' yet published. In a carefully planned trial t h e y assessed the effect of 'dipasic' on I I patients, io of whom were producing strains resistant to isoniazid and PAS, the remaining I having a culture resistant 0nly to isoniazid. All the strains were also at least ten times more resistant to 'dipasic' than the control strain H37Rv. Detailed studies failed to show any effect of 'dipasic' on the bacterial population, nor was there any clinical effect. The conclusion drawn in this report was that there was no evidence to suggest that 'dipasic' had an action independent of its PAS and isoniazid content both bz vitro and in vivo.

On tile other hand Brodhage (I954) reported that seven out of thirty-two strains of bacilli resistant to PAS and isoniazid were sensitive to 'dipasic'. I t was suggested by Walker and others, supported by the evidence of Bringer and Sclatitze (1955) , Schaub (1955) and Rist (1957) that the small amount of PAS in 'dipasic' may be sufficient to give rise to confusion in bz vitro tests by causing isoniazid resistant tubercle bacilli to appear to be sensitive to 'dipasle'. This must depend on the assumption that 'dipasic' is an unstable compound which decomposes under bz vitro conditions to liberate PAS and isoniazid. Kourilsky and others (x956) and Kakimoto and Yamamoto (i 956) suggested that it is in fact a more stable compound with individual properties of its own. hz vh'o, however, Unverricht and others (I955) and Bringer and Schiitze (i955) found by paper chromatographic studies that the drug is split up in ' the duodenum, at least in part, int O isoniazid and PAS.

Our sensitivity results suggest that resistance to isouiazid during 'dipasie' treatment may occur readily. Out of 15 patients with cultures intially sensitive to isoniazid I I later had cultures resistant to isoniazid in varying degrees. Resistance to 'dipasic' after treatment was present in only 3 patients of this group. The clinical and radiographic response of the x6 patients with initially isoniazid resistant bacilli was in some respects interesting. Subjectively, just under half reported improvement in cough, sputum, appetite and well being. This improvement might be attributable to the use of a 'new drug', but 5 out of the x6 also showed weight gains and 4 x-ray improvement. One patient, moreover, became persistently sputum negative with x-ray improvement and weight gain. It is well known that a single resistant culture does not preclude later clinical, radiographic and bacteriological improve- ment during continued treatment with the drug concerned. The occurrence of such improvement in one of our patients with isoniazid resistant cultures is not proof that the 'dipasic' was acting in any other way than through its isoniazid content.

~DIPASIC' o 0 5

Summary Ninety- three out-pat ients with chronic p u l m o n a r y tuberculosis received 'dipasic ' for vary ing periods. Forty-two had spu tum sensitivity results avai lable before treat- ment . Sixteen of these had isoniazid resistant strains and the clinical, radiographic and bacteriological changes in these patients are recorded.

Twenty-seven patients had sp.utum sensitivity results avai lable both before and after t rea tment . In I5 the init ial cultures were isoniazid sensitive a n d in I I of these isoniazid resistant strains were obta ined after t reatment .

We would like to thank Dr J. Wallace Craig, physician in charge at Islington Chest Clinic for kind permission to use patients' records and Dr G. P. Maher-Loughnan for his helpful advice and criticism. Our thanks are also due to Dr J. M. Alston, pathologist in charge, Archway Group Laboratory, and Dr Mary Simpson for access to bacteriological records and for advice on methods used. Our office staff have provided us with invaluable clerical assistance.

References B6hlke, E., and Schoeps, U. (1956) Beitr. klin. Tuberk., 115, I45. Brodhage, H. (1954) Science, 12o, 998. Bringer, P., and Schiitze, G. (1955) TuberkArzt., 9, 58I • Clegg, J. W. (I955) Brit. reed. 07, ii, Ioo4. Cuthbert, R. J., Drimmie, A. M. T., and Urquhart, K R. (1958) Tubercle, Lond., 39, 154. Freudenthal, A. (1955) Patronato Nacional Antituberculosis, 'Flor de Mayo', Barcelona. Kakimoto, S., and Yamamoto, K. (1956) flap. 07. Tuberc., 3, 84. Klose, G., and Mertens, J. (1956) Praxis, 45, 1o45. Kourilsky, R., Kourilsky, S., and Thuillier, Y. (i956) Sere. ttdp. Paris, 3 ~, 1948. Krug, F. (1954) ,~liinch. reed. IVschr., 96, 1 I',6. l~fackie, T. J., and McCartney, J. E. (1953) Handbook of Practical Bacteriology, 9th ed., E. & S.

Livingstone, Edinburgh. Rist, N. (t957) Rez'. Prat. Paris, 7, 304. Schaub, R. (1955) Beitr. klbz. Tnberk., 113, 33 t. Smith, A. E. W., and Wiederkehr, F. X. (1953) Praxis, 42, 884. Unverricht, W., Koehn, A., Renovanz, H. D., Senft, G., and Schattman, N. K. (t955) Beitr. klin.

Tuberk., xx4, 528. Walker, W. C., Ha)5 D., Stewart, Sheila M., and Crofton, J. W. (1957) Tubercle, Lond., 38, 238.