Journal of Postgraduate Medicine
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Year : 1978  |  Volume : 24  |  Issue : 3  |  Page : 182-185  

Clonidine as an antihypertensive drug in diabetics

SD Bhandarkar, KS Vernekar 
 Department of Diabetes & Endocrinology, K.E.M. Hospital, Parel, Bombay 400 012, India

Correspondence Address:
S D Bhandarkar
Department of Diabetes & Endocrinology, K.E.M. Hospital, Parel, Bombay 400 012


Clonidine was administered as an antihypertensive agent to 20 diabetic patients stabilized on oral hypoglycemic agents. The study lasted for three months. Sixteen patients completed the study. No patient complained of hypoglycemic symptoms. All patients show­ed a good control of blood pressure. Only two patients showed a rise in post lunch blood sugar level on one occasion each during treatment. There was no significant change in the blood sugar levels in the remaining patients. In conclusion, clonidine does not appear to significantly alter the diabetic control by oral hypo­glycemic drugs.

How to cite this article:
Bhandarkar S D, Vernekar K S. Clonidine as an antihypertensive drug in diabetics.J Postgrad Med 1978;24:182-185

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Bhandarkar S D, Vernekar K S. Clonidine as an antihypertensive drug in diabetics. J Postgrad Med [serial online] 1978 [cited 2022 Aug 20 ];24:182-185
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Full Text


Clonidine is a useful antihypertensive drug. Hypertension and diabetes are both common diseases and frequently co-exist. The following study was undertaken in the Diabetes Clinic of the K.E.M. Hospi­tal Bombay, to determine if clonidine had any deleterious effect on the regulation of the diabetic state.

Literature on this subject is scant and comprises mostly of the experimental work in animals. Clonidine has been shown to produce the following effects: (1) hyperglycemia following an injection into the vertebral artery in cats [1] (2) re­duction in catecholamine release in res­ponse to hypoglycemia in man [7] and (3) increased hepatic glycogenolysis follow­ing intravenous administration in cats. [8]

 Material and Methods

Twenty diabetic patients with hyper­tension were studied. They were selected on the following basis.

They were on oral hypoglycemic agents (chlorpropamide and/or phenfor­min) and were well controlled continu­ously for at least six months.Their hypertension was either new­ly detected, or old but not controlled with other antihypertensive drugs or they were intolerant of them.

Patients with following were not con­sidered for this study:

Patients on insulin.Patients not well controlled on oral hypoglycemic drugs.Patients with hypertension already well controlled with another antihyper­tensive drug.

Only those patients who were well con­trolled for at least 6 months with oral hypoglycemic drugs were selected because in such patients a change in the blood sugar, if any, could possibly be attributed to the added drug, clonidine. Patients treated with insulin were excluded be­cause many of them tend to have fluctuat­ing blood sugars and, therefore, it would be difficult to separate the effect of cloni­dine on blood sugar level, if any, from the spontaneous fluctuations in the latter.

All the patients had a fasting and post­lunch true blood sugar determination (Nelson Somogyi method) before com­mencing the study and at monthly inter­vals for 3 months (which was the duration of the study). They had their blood pres­sure in the right arm determined in the sitting position before commencing the study, and at 15 days' intervals during the entire period of study.

The patients were supplied clonidine tablets* for 8 days at a time and at every visit they were questioned by the same person (K.S.V.) about the appearance of any new symptoms since their last atten­dance.

Clonidine was started in the dose of 50 µg 3 times a day and the dose was gra­dually increased at weekly intervals to a maximum of 200 µg. 3 times a day.


[Table 1] shows the results.

Sixteen patients completed the 3 months' trial, 2 patients dropped out on their own, and the drug had to be discontinued in 2 patients because of adverse effects. The blood pressure was well controlled in all patients. The average dose of 'clonidine was 282 µg/day in 3 divided doses, the range being 150-500 µg/day.

The mean systolic blood pressure of the whole group was 168.6 mm.Hg. and the mean diastolic blood pressure, 105, mm. Hg. before the treatment. During the treatment the mean systolic blood pres­sure of the group was 148 mm. Hg. and the mean diastolic blood pressure, 91.5 mm. Hg Thus there was a drop of 20.6 mm. Hg. systolic and a drop of 13.9 mm. Hg. diastolic pressure in the whole group. It took an average of two weeks for blood pressure to be controlled, the range of 1 to 6 weeks.

The mean fasting blood sugar level be­fore commencing clonidine was 99.2 mg.% and the mean post lunch blood sugar level was 110.6 mg%. While on the drug, the figures were 94.7 mg% and 112.6 mg%, respectively.

In two patients, one intra-treatment post lunch blood sugar value was higher than the pretreatment post lunch blood sugar value by 60 mg% and 32 mg% respectively.

Adverse Effects:

Two patients complained of unpleasant symptoms; one had persistent giddiness and frequent vomiting, and the second had generalised weakness, malaise, mus­cular pains, nausea and involuntary movements of limbs. Clonidine was omit­ted in these two patients. No patient complained of hypoglycemic symptoms.


As diabetes and hypertension frequent­ly coexist, it is useful to have an anti­hypertensive drug which does not alter the carbohydrate tolerance adversely. Thiazides [3] and diazoxide [2],[9] have been re­ported to cause hyperglycemia. Proprano­lol [4] and gaunethidine [5],[6] are known to potentiate the hypoglycemic effects of in­sulin and oral hypoglycemic agents. In this short-term study, we did not observe any deleterious effect of clonidine on the control of diabetes with oral hypoglycemic agents, except in two patients in whom elevation of single post lunch blood sugar values was seen during treatment. The blood pressure was controlled satisfacto­rily in all patients. Only two patients complained of unpleasant symptoms which necessitated discontinuation of clonidine.


This study was carried out under the auspices of the Seth G.S. Medical College and K.E.M. Hospital Research Society with financial assistance by M/s. Unichem Laboratories Ltd. We are grateful to both of them. We thank Mrs. K. D. Lotlikar, M.Sc., Bio-statistician, for carrying out statistical analysis of the data. Finally, we thank the Dean, Seth G.S. Medical Col­lege & K.E.M. Hospital, for permission to carry out the above study and to publish this report.


1Bock, J. U. and Zwieten, P. A.: The central hyperglycemic effects of Clonidine. Euro. J. Pharmac., 16: 303-306, 1971.
2Cutbert, S. and Sharp, R.: Diazoxide­Modification of streptozotocin induced diabetes in rats. Diabetes, 23: 282-286,1974.
3Dollery, C. T.: Diabetogenic effect of long term diuretic therapy. In, "Modern Diure­tic Therapy", Experta Medica, Amsterdam,1973, pp. 320-330.
4Goodman, L. S. and Gilman, A.: "The Pharmacological Basis of Therapeutics", 5th Edition, MacMillan Publishing Co..New York, Collier MacMillan, Canada Ltd. and Bailliere Tindall Co., London, 1974, pp. 552.
5Gupta, K. K. and Lillicrap, C. A.:Guanethidine and diabetes. Brit. Med. J., 2: 697-698, 1968.
6Gupta, K. K.: Gaunethidine and glucose tolerance in diabetics. Brit. Med. J., 3: 679, 1968.
7Hedeland, H.. Dymling, J. F. and Hokfelt, B.: Pharmacological inhibition of adrenaline secretion followinig insulin Induced hypoglycemia in man-The effects of catapresan. Acta. Endocrinol., 67: 97-103, 1971.
8Rehbinder, D. and Deckers, W.: Stoff­wechseleffekte der catapressan, Naunyn­Schmeidebergs. Arch. Pharmak. Exp. Pathol., 261: 162-175, 1968.
9Speight, T. M. and Avery, S. S.: Dia­zoxide, a review of its pharmacological properties and therapeutic use in hper­tensive crisis. Drugs, 2: 78-137, 1971.

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