EFFECTIVE BLOOD PRESSURE CONTROL

· .. Hydrochlorothiazide/Triamterene Combination Is as Good as Hydrochlorothiazide/Spironolactone 92 patients with mild to moderately severe hypertension were involved in a niulti·investigator, double·blind 8-week study to compare the efficacy of triamterene and spironolactone combined with a hydrochlorothiazide [I]. They were equally effective, with the same incidence and type of side·effects. All antihypertensive drugs were discoptinued.4 weeks before the tesL 46 patients were given PO a capsule with 50mg triamterene plus 25mg hydrochlorothiazide ('Dyazide'j Smith, Kline and French), the other 46 were given 25mg spironolactone plus 25mg hydrochlorothiazide ('Aldactone'j Searle), bid, but altered to a maximum of qid depending on the patient's response. Supplemental potassium was not prescribed. The overall Global Efficacy was similar for both drugs: 36/44 (82 %) for triamterene + hydrochlorothiazide, and 35/44 (80 %) for spironolactone + hydrochlorothiazide: Side-effects (headaches, dizziness and weakness) were approximately equal in both groups. One patient· on triamterene discontinued owing to gastrointestinal and leg pains, and 1 on spironolactone owing to diarrhoea. There were no significant differences between the 2 groups in blood chemistry or haematology.

· .. Long-Term Frusemide Compares Well With Hydrochlorothiazide Little information exists on the long-term efficacy and safety of diuretics used alone or combined with other drugs which lower blood pressure. In a 2-year double·blind study in 52 outpatients with essential hypertension frusemide (furosemide; 'Lasix') 40mg bid in 26 patients was compared with hydrochlorothiazide SOmg bid in 26 patients [2]. Both drugs significantly lowered BP from baseline levels. At 4 and 8 weeks and 18 months the decrease was less with fniseinide than with hydrochlorothiazide, while at other times the difference was not significant. Two (8 %) of the frusemide patients were diagnosed as hypokalaemic, vs 16 (62 %) of those on hydrochlorothiazide. The clinical importance of this was not clear.

· .. Prazosin Hydrochloride Gives'Effective Control In a trial in 39 patients with diastolic BP over IOOmm Hg, 29 were untreated, newly diagnosed, and 10 had responded poorly or had bad side-effects on large doses of methyldopa, guanethidine and.debrisoquine after 6-20 months' therapy [3]. The 29 were treated with prazosin hydrochloride, 3g/day (25) or 6g/day (4). In those not showing a satisfactory response the dosage was increased by 3mg/ day every 2-4 weeks to a maximum of IS-20mg/ day. A diuretic was added if inadequate response was obtained. Propranolol was given if tachycardia developed. For the 10 other patients, prazosin 3mg/ day was added to the existing regimen, and therapy continued for 4-18 months. The mean daily dose of prazosin in mild, moderate and severe BP patients was 3.7mg, 6.1 mg and 9mg respectively. In addition, 14 patients received O.5mg chiorthiazide, and 9 propranoloI40·120mg/day .

• Of the 29 new patients, 21 (72 %) had a satisfactory fall in supine, and 22 (76%)1n erect diastolic, BP. The mean fall was 30mm Hg in systolic(p < 0.01) and 18mm Hg in diastolic(p < 0.01) supine BP. The mean fall was 32mm Hg in systolic (p < 0.01) and 19mm Hg in diastolic (p < 0.01) standing BP .

• Of the other' 0 patients, 7 had a fall from a mean systolic BP of J6S .. 7nim Hg to 138.5mm Hg, and from a mean diastolic BPof I08.5mmHg to 87.lmm Hg.

'This present study shows that Prazosin Hydrochloride can effectively control arterial blood pressure in the majority of patients with different ranges of blood pre.~sure both in the untreated and treatment failure group . Therefore regardless of which drugs are ultimately used, the regimen of vaso·dilation, beta-adrenergic blockade and volume depletion appears to be a promising new approach to the treatment of hypertension. '

(I] Cocke, B.T. et aI .: Journal of Clinical Pharmacology 17: 334 (May 1977) [2J Finnerty, FA el aI.: Angiology 28: 125 (Feb 1977) {3] feng. P.H. et aI. : Annals of the Academy of Medicine, Singapore 5: 151 (Apr 1976)

INPHARMA 16th July. 1977 p12