MR Pharmacist, I was involved in a motor accident a few days ago.
I was in so much pain (at my back) after and went through a number of investigations by my health care provider. Nothing untoward was found at the time and I was put on these pain killers.
The medicines were Tablets. Paracetamol 500mg to be taken every eight hours.
There was also Capsule Tramadol 50mg to be taken every eight hours and tablets.Diclofenac 50 mg to be taken every eight hours. All the medicines were to be taken after food.
The client mentioned that the pharmacist stressed that the Tablets. Diclofenac 50mg should be taken only after food to prevent any stomach discomfort.
Mr. Pharmacist, my main problem now is constipation. The pain is much better since the incident but I have noticed a complete change in my bowel movement.
I used to visit the loo once every day but it is completely different now. I have not moved my bowels for the past three days and it is making me very uncomfortable.
If these are the only medications you are taking now then it is very likely that the constipation is due to the intake of Tramadol.
Tramadol is a synthetic codeine look-alike that is a weak u-opioid receptor agonist. Part of its analgesic effect is produced by inhibition of uptake of norepinephrine and serotonin.
Tramadol consists of two enantiomers , both of which contribute to analgesic activity through different mechanisms.
An enantiomers is one of the two molecules that are mirror images of each other and are non-super- posable.(+) Tramadol and the metabolite (+)-O-desm ethyl-Tramadol (M1) are agonists of the mu opioid receptor. (+)- Tramadol inhibits serotonin re uptake and (-)-Tramadol inhibits norepinephrine re uptake, thereby enhancing inhibitory effects on pain trans- mission in the spinal cord.
The complementary and synergistic actions of the two enantiomers improve the analgesic efficacy and tolerability profile of the racemate (Tramadol).
The O-demethylation of Tramadol to O-des methyl-Tramadol (M1) which is the main analgesic effective metabolite is catalysed by cytochrome P450 (CYP) 2D6. The N-demethylation to M2 is catalysed by CYP2B6 and CYP3A4..
These complexities in the dynamics of Tramadol within the system accounts for the variability in its outcome in different persons. Some persons may not have such problems with constipation. It is very useful for the treatment of mild to moderate pain.
On a dose-by-dose basis Tramadol has about one-tenth the potency of morphine for pain relief. Tramadol provides postoperative pain relief comparable with that of Pethidine.
The analgesic potency of Tra- madol just like opioids can be improved by the combination therapy with non-opioids such as Paracetamol and Diclofenac.
This is exactly what was done in the case of the client permitting the use of a daily dose of 150mg Tramadol (maximum daily dose is 400mg).
Since you are now better in terms of pain relief I will suggest you see your health care provider for a review. Constipation is an adverse effect of Tramadol.
You will usually be cautioned about this effect on starting the drug. There is a reputable medical reference site-Medscape.
The percentage of persons likely to suffer constipation when taking Tramadol is between 24-46 per cent. Constipation ranks as the most prominent adverse effect of Tramadol.
The client asked whether there were other medicines that could also cause constipation. Yes, there are several.
Tramadol is described as a drug with opioid-like or morphine-like properties. If Tramadol can cause constipation then the effect of real opi- oids such as Morphine, Dihydro- codeine, Codeine, will be bigger.
At this point it is important to caution the use of some cough preparations. Opioids are used a lot in cough preparations because of their anti- tussive effect.
They may be there as codeine or, dextropropoxyphene. Such preparations taken together with Pain-relievers would cause in- creased constipation.
It is common for persons with stomach aches or discomfort to take antacids as first aid. But one needs to be careful about the use of antacid to use in such situations.
A client with constipation in- duced by opioids should not take antacids containing Aluminium salts such as Aluminium Hydrox- ide (Aludrox).
This is likely to make the con- stipation worse. A typical one is Aluminium Hydroxide (Aludrox). For instance if you were having stomach ache in addition to constipation and took Aluminium Hydroxide, the constipation will become worse. Iron supplements could also cause constipation.
This effect is however variable since some persons express iron intolerance by passing loose stool. Persons on tricyclic antidepres- sants such as Amitriptylline are also prone to constipation through their anti-muscarinic effect.
This leads to decrease in gastrointestinal motility and reduced peristalsis in the intestine. Bromocriptine, a medicine used in persons with Parkinson’s disease and also to curb excessive lactation is known to cause con- stipation.
If you are taking a fixed-dose anti hypertensive containing chlor- thalidone then you should expect to experience constipation.
The general advice to clients on opioids such as Morphine, Codeine, Dihydrocodeine (or opi- oid-like Tramadol) is to take lots of orange and pawpaw and drink lots of water. Be also mindful of other med- ications which may worsen the constipation.
Also quickly get back to your health care provider for a review. It is the beginning of the year. Check out your medicines cabinets and clear them out.
The Disposal of Unused Med- icines Programme (DUMP) is on-going. We are ever-ready to assist.
By Edward O. Amporfu