Dihydrocodeine/Paracetamol

Irreversible reaction of [18] iodine with acetylsalicylic acid, aethaverine, amidopyrine, ascorbic acid, benzo-caine, quinine, dihydrocodeine, fluorescein, glycine, hydrocortisone acetate, isoni-azid, metamizole, papaverine, paracetamol, phenacetin, phenol-phthalein, piperazine, resorcinol, salicylic acid, salicylamide, sulfaguanidine, thymol, triethanolamine, tris buffer detection by reaction chromatography... 

Something of a stereotype now follows, but in a good cause to illustrate some practical points in management of minor opioid misuse. I would contend that there is a syndrome of a classic case of someone who becomes dependent on paracetamol and codeine combinations, or dihydrocodeine, dextropropoxyphene or something similar, with the following features ... 

Lloyd, R.S., Costello, F., Eves, M.J., James, I.G., Miller, A.J. The efficacy and tolerability of controlled-release dihydrocodeine tablets and combination dextropropoxyphene/paracetamol tablets in patients with severe osteoarthritis of the hips, Curr. Med. Res. Opin. 1992, 13, 37-48. 

The doctor caring for AW asks your advice regarding analgesia. So far he has prescribed regular paracetamol and full-dose dihydrocodeine but AW is still in severe pain. What recommendations can you make regarding analgesia for AW ... 

This chapter concentrates on some drug choices in acute rather than chronic pain, but the same principles can be used to determine the appropriateness of other types of analgesic. The drugs considered in this section are paracetamol, non-steroidal anti-inflammatories (NSAIDs specifically diclofenac, ibuprofen, indometacin, naproxen, sulindac and tenoxicam) and opioids (codeine, dihydrocodeine, morphine, pethidine and tramadol). Unless otherwise stated, all pharmacokinetic data originate from standard reference sources [1-5] and apply to adults only. 

In a fatality attributed to an oral overdose of dihydrocodeine, the following postmortem tissue concentrations were reported blood 12 pg/ ml, bile 5340pg/ml, liver 620pg/g, urine 570pg/ml chlordiazepoxide was also detected. In a second case in which the death of an addict occurred rapidly after an intravenous overdose of dihydrocodeine, the postmortem concentrations were blood 720pg/ml, bile 3pg/ml, liver blood 364pg/ml, urine 7 pg/ml pentobarbitone and paracetamol were also detected (M. A. Peat and A. Sengupta, Forens. Sd., 1977, 9, 21-32). 

Analgesics. Avoid if possible, all NSAIDs including aspirin (but see p. 576, myocardial infarctionjbecause of their irritant effect on gastric mucosa and action on platelets. Paracetamol is acceptable but doses over 1.5 g/d may raise the INR. Dextropropox5q>hene inhibits warfarin metabolism and compounds that contain it, e.g. co-proxamol, should be avoided. Codeine, dihydrocodeine and combinations with paracetamol, e.g. co-dydramol, are preferred. 

Codeine is combined with aspirin, paracetamol and ibuprofen in many OTC analgesic products, and also in the formulary preparations co-codamol (with paracetamol) and co-codaprin (with aspirin). Dihydrocodeine is included with paracetamol in one OTC product, and at a higher dose in co-dydramol tablets, which are prescription-only medicines (POM). 

Analgesic preparations are all based on one of three drugs - aspirin, paracetamol and ibuprofen - sometimes in combination with the ancillary analgesics codeine or dihydrocodeine, or with other constituents that are claimed to increase effectiveness. (Author s note please check and amend at proof stage An application has been made for P classification for naproxen for PD, and it may be reclassified before the book is published.)... 

There are also several proprietary preparations combining paracetamol or ibuprofen with codeine, and a paracetamol/dihydrocodeine combination (nonproprietary co-dydramol tablets contain a higher dose of dihydrocodeine and are prescription-only (POM)). 

The patient s constipation could be caused by dihydrocodeine in the co-dydramol tablets constipation is a common side-effect of opiate analgesics. You could suggest that she try taking paracetamol alone, to see if that cured the constipation. If it did but did not control the arthritic pain sufficiently, you could suggest that she stays on co-dydramol and asks her general practitioner to prescribe a laxative - lactulose may be appropriate - for the constipation. 

Both codeine and dihydrocodeine are widely used analgesic drugs, often formulated in combination with aspirin or paracetamol (e.g. cocodamol, co-dydramol). 

There are only 5 published case reports of a possible interaction between paracetamol without opioids and a coumarin (warfarin or acenocoumarol), which are summarised in Table 12.5 , (p.439). In addition, there are two reports of a possible interaction with paracetamol combined with codeine or dihydrocodeine listed in Table 12.5 , (p.439), and 7 others with paracetamol combined with dextropropoxyphene (propoxyphene) , (p.436). Note that this incidence is very rare, given the widespread use of paracetamol, and the fact that it is generally considered safe for use with warfarin. 

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