NEEDLE PLUGGING AND INSULIN INJECTION

681 cancer risk-is reasonably well established. Given this sequence, a public health approach would demand intervention at all stages: public education to prevent people starting to smoke; pharmacological or behavioural treatment to help tobacco addicts to stop smoking; and surgical excision of lung carcinoma for those who become afflicted. Interventions at each stage require assessment as to efficacy, safety, and

ing, addiction,

cost.

These criticisms should not overshadow the importance of Brown’s work to the attention of physicians; depressions are the most prevalent of adult psychiatric disorders and are usually treated to non-psychiatrists.

bringing

Harvard Medical School, Boston, Massachusetts, U.S.A.

GERALD L. KLERMAN

Depression Research Unit, Connecticut Mental Health Center, New Haven, Connecticut,

06519

that the suspended crystals cannot easily pass through the narrow constriction between the needle bevel and the subcutaneous tissue. The probability of blockage appears to increase if the injection is given slowly but it is not clear what the injection-rate has to be to avoid blockage. Since most insulin syringes used in North America are disposable the problem is not due to inadequate cleaning of reusable needles. It has been reported that spontaneous blockage cannot be induced by storing filled syringes with the needle downward. In view of these findings, the reason for plugging during adjustment of the dosage as reported by Dr O’Mullane and Dr Robinson (July 15, p. 165) is difficult to explain.. Clinical Devices Division, Bureau of Medical Devices, Health and Welfare Canada, Tunney’s Pasture, Ottawa, Canada

PHILIP D. NEUFELD

MYRNA M. WEISSMAN

PHOTODEGRADATION OF DACARBAZINE NEEDLE PLUGGING AND INSULIN

INJECTION

SiR,—Needle plugging during injection of insulin has been reported to us on several occasions and has attracted notice in the United States and, lately, in your correspondence columns. In January, 1976, the U.S. Food and Drug Administration held a meeting with manufacturers, and the July, 1976 issue of Diabetes carried an F.D.A. appeal for information on this problem. Although the exact cause is not well understood, the reports share certain characteristics which suggest a possible mechanism. Most cases occur with crystalline insulin suspensions such as lente or ultralente, and in North America the problem reports seem to have begun with the widespread use of the U-100 (100 units/ml)concentration in 1973. We have simulated this plugging in glass micropipette tubing cemented to a needle hub attached to a 1 ml syringe filled with U-100 lente insulin. The bore of the tubing was roughly 0.38 mm, which corresponds to a 22 or 23 gauge needle, a fairly large size for insulin injection. The end of the tubing was held with moderate pressure against a wad of paper tissue or a. finger tip and the insulin was expressed slowly. Crystals rapidly accumulated at the tip of the tubing and the flow was sometimes blocked before 0-5ml had been ejected (see figure). This suggests that the plugging is caused simply by the fact

SiR,—There is evidence that the anti-tumour drug dacarba-

(D.T.I.C., dimethyltriazeno-imidazole carboxamide) is susceptible to photodegradation in solution’ and, as commonly administered, its breakdown products (including 5-diazoimidazole carboxamide and 2-azohypoxanthine) may be responsible for the troublesome local venous pain and other systemic sideeffects such as nausea, vomiting, and hepatic toxicity. Having regularly seen these side-effects we have lately tried reconstituting and rapidly injecting the drug at a concentration of 100 mg in 10 ml in a room lit by a red photographic lamp only. In a total of fourteen such injections in three patients pain was entirely eliminated or reduced to minor discomfort during the first few seconds. These patients had previously experienced moderate to severe pain along the vein throughout the injection. There also seemed to be less nausea and vomiting. The improved patient acceptability was striking. Evidence that the tumoricidal value of D.T.I.C. is enhanced by preventing photodegradation will be less easy to obtain. zine

Department of Hæmatology, Royal Hospital for Sick Children, Glasgow, G3 8SJ

GILLIAN M. BAIRD M. L. N. WILLOUGHBY

ABUSE OF BENZODIAZEPINES

Simulated needle plugging with U-100 lente insulin.

Upper. crvsta) blockade at end of microptpettc tubing. I.oBvcrr mat;mticaoun shwang plug of msutm crystals.

SIR,-It is worth reinforcing the hazards of prescribing psychotropic drugs to recovered alcoholics. A 42-year-old man was admitted to my alcohol treatment programme this year with a history of an alcohol-related divorce, two to three bottles of whisky per day from early morning onwards, black-outs, amnesias, and so on. He had been an inpatient at another hospital and had gone to Alcoholics Anonymous meetings in the hope of curing his addiction, but without success. His progress was satisfactory and he was discharged at the end of the six-week programme but things soon went badly. He had, before admission, been prescribed various tranquillisers, and he now became addicted to lorazepam, behaving with lorazepam precisely as he had with alcohol: he lied in order to obtain supplies, which he then hid surreptitiously around the house, and he took unknown quantities of the drug: "After the first three or four you don’t know how many you have taken". Calculations suggested that he took at least 80 2.5 mg capsules between 5 P.M. and 10 A.M. the next morning. Withdrawal symptoms of tremor, guilt, and remorse were precisely as they were with alcohol and his erratic behaviour was identicallying and illogical, hazardous conduct (e.g., putting an empty saucepan on the cooker). "You blank out the same as you do with alcohol." 1

Shealy, Y , Krauth,

C. A,

Montgomery, J. A. J.

org. Chem

1962, 27, 2150