BRINGING THAT BLOOD PRESSURE DOWN

... Bethanidine and Oxprenolol Combination Has Many Advantages The combination of several drugs has been shown to control hypertension better. and with fewer side-cffects. than larger doses of sinsle drugs. II combinalion ofbcthanidine(' Esbatarl and oxprenolol ('Trasicor') was compared wilh /)elhanidinealune in ]2 patients[l]. Belhanidine was started at 5mg lid. with weekly Sms increments ifnecessary. After a fa ll of 20mm Hg in theercct mean arterial pressure was maintained for) weeks without [urther bethan idine. oxprcno]o) 40mg bid was added. wilh a 40mg bid increment each week until the re.'i ling supine diastolic pressure had fallen to 90m m Hg and been maintained for 6 weeks without fu n her increments of oxprenolol. Belhanidine was then graduall y reduced unt il control was threatened .

• In 3 patients bethanidine could be withdrawn: in 10 no reduction was possible without loss o f control: and in the remainder a 38 % reduction was ach ieved . Four. controlled on bethanidinc. never ro:::eived ox.prenolol.

e There were fewer side-efTects (9) with the combination than with bethanidine alone (14). Except for 2 cases. none was serious.

'The flelCibility of the regimen. which permitted adjustments in dosage without loss of hypotensive effect once control had been established, suggests the com­bination has many possible advantages and few, if any, obvious disadvantages.'

... Bethanidine with Sotalol is Effective and Acceptable A comparison of50la101 and bethanidine with sota101 alone further supports Ihe use ofanlihypenensivedrugs in combination [2}. In 24 patients wilh essential hypertension, treatment was started with 5Otalol 40mg tid wilh weekly increments of SOmg if needed, toa maximum of 400mg daily. After a month on either an effective or maximum dosage of sou\ol,treatment with bethanidine was started with SOlg tid. increased by Smg each week ifnettSSary. Of 30 patients given only sotaiol. 24 were controlled without side-effectson 400mg or less daily. Seven mild and transient side-effects were recorded in Ihis group and 4 in the group receiving the combination . There were no treatment failures.

INPHARMA 23rd Julv. 1917 plQ

... Oiazoxide Works Fas ter. lasts longer. Causes less Tachycardia than HydraUazi ne Parenteral diazoxide and hydralhnine arc the 2 most powerful drugs not requiring constant monitori ng and drip infusion for the treatment of severe hypertension. They were compared in 12 patienlS with severe hypertension , 6 received diazoxide 300mg in 20ml volume by rapid IV injection (with fruscmide). and 6 received hydrallazine 20mg 1M repeated in 2·4 hours as necessary (with oral diuret ic and alphamethyldopa begun simul tanoously)[3L

• Diazoxide worked faster than hydrallazine- onset of action was mallimal at 2·5 minutes and la. .. ted up to 12 hours. Hydrallazine's maximal effect was al about I hour. Response to 2nd doses was si milar 10 1st with both drugs. There was a s lightly greater and more sustained tachycardia with hydrallatine .

. . . Prazosin and Hydra llazine Both lower BP but Prazosin Has Fewer Side-Effects In the first study 22 p8liems with hypertension were given 40mg propranolol tid and chlorOlhiazide 0.5g bid for 4 weeks [4]. BP remained above I OOmm Hg in ' 0 patients. who were Ihen given. randomised and double·blind. an additional I rug prazosin or 25mg hydra llazine tid . increased 10 a maximum of 5 limes the dose, o r unti l diastolic BP was reduced 10 below 95mm Hg within 12 weeks. Two patients left the study. Diastolic BP was effectively reduced in 7 patients by Iheaddition of either drug. and in I

palient by the addition of both drugs. Non-disabl ing side-effecLS included headache. dizziness. tiredness and nausea. No abnormalities were found in routine investigations. In Ihe second study 24 known responders to prazosin or hydrallazine. while remaining on their original antihypertensive drug lherapy. were given double·blind. either I mg prazosin or 25mg hydrallazine, adjusted 10 achicve optimum diastolic BP control over two 6-week crossover periods. Eight patients developed serious side-effects - headache, palpitations. flushing. nausea, vom iting and dizzi ness -and len the study in the 1st week. The relative 'dose equivalence· ·wa. .. I mg prazosin 10 20mg of hydrallazine for similar antihypertensive effect. The ereet dias tolic BP tended 10 be lower wilh prazosin than hydrallazine. and lower still when both drugs were used in combination. Prazosin produced fewer side-effects than hydrallazine. Ihough nasal congest ion was unusually common. No significant abnormalities were found on routine blood and urine investigations.

[I) Rowlands. G. tl aJ .: P riOClitio~r 219: lOS Oul 1977)

(2) RD W!IIIld~. G. tt aJ .; British Journal oretinal PllIctia: J I: 57 (May 19771

III tbll!len. D.P.: E- Arricln Modicll Journal 54: 61 (No 2. 1977)

141 Hua. A.s.P. et III. : Medil:alJoumal or AUSIralioo 2: S (2 Jul (977)

INPHARMA 23rd July, 1977 pll