Summary of Product Characteristics (SmPC) - Doans Backache Pills
1 NAME OF THE MEDICINAL PRODUCT
Doans Backache Pills
2 QUALITATIVE AND QUANTITATIVE COMPOSITION
Active ingredients: Paracetamol BP 150mg
Sodium Salicylate BP 100mg
For the full list of excipients, see section 6.1.
3 PHARMACEUTICAL FORM
Tablets
4 CLINICAL PARTICULARS
4.1 Therapeutic indications
For the symptomatic relief of rheumatic aches and pains, including backaches sprains lumbago, fibrositis, muscular aches and pains.
4.2 Posology and method of administration
Posology
Adults: 2 or 3 tablets every 4 hours. Do not take more than 16 tablets in any 24 hour period.
Children: Do not give to children under 16 years, unless specifically indicated (e.g. Kawasaki’s disease).
Method of administration: Oral.
4.3 Contraindications
Hypersensitivity to the active substances or sodium salicylate, aspirin or paracetamol or to any of the excipients listed in section 6.1
Doans Backache Pills should not be given to patients suffering from peptic ulceration, gout or haemophilia.
4.4 Special warnings and precautions for use
Use with caution in asthmatic patients.
Care is advised in the administration of paracetamol to patients with severe renal or severe hepatic impairment.
The hazards of overdose are greater in those with non- cirrhotic alcoholic liver disease. Do not exceed the recommended dose.
Cases of high anion gap metabolic acidosis (HAGMA) due to pyroglutamic acidosis have been reported in patients with severe illness such as severe renal impairment and sepsis, or in patients with malnutrition or other sources of glutathione deficiency (e.g. chronic alcoholism) who were treated with paracetamol at therapeutic dose for a prolonged period or a combination of paracetamol and flucloxacillin. If HAGMA due to pyroglutamic acidosis is suspected, prompt discontinuation of paracetamol and close monitoring is recommended. The measurement of urinary 5-oxoproline may be useful to identify pyroglutamic acidosis as underlying cause of HAGMA in patients with multiple risk factors.
The labels will say: Do not take with any other paracetamol containing products. Immediate medical advice should be sought in the event of an overdose, even if you feel well.
The leaflets will say: Immediate medical advice should be sought in the event of an overdose even if you feel well because of the risk of delayed serious liver damage.
If symptoms persist, consult your doctor. Keep out of the reach of children. There is a possible association between aspirin and Reye's Syndrome when given to children. Reye’s Syndrome is a very rare disease which affects the brain and liver and can be fatal. For this reason, it should not be given to children under 16, unless specifically indicated (e.g. Kawasaki’s disease).
Important information regarding the ingredients of this medicine
Sodium: This medicine contains less than 1 mmol sodium (23 mg) per tablet, that is to say essentially ‘sodium-free’.
4.5 Interaction with other medicinal products and other forms of interaction
Paracetamol- potentiation may occur with the coumarin anticoagulants. Interactions with cholestyramine and metoclopramide have also been reported, reducing absorption of the former and potentiating the action of the latter. The anticoagulant effect of warfarin and other coumarins may be enhanced by prolonged regular use of paracetamol with increased risk of bleeding occasional doses have no significant effect.
The speed of absorption of Paracetamol may be increased by metoclopramide or domperidone and absorption reduced by Cholestyramine.
Caution should be taken when paracetamol is used concomitantly with flucloxacillin as concurrent intake has been associated with high anion gap metabolic acidosis due to pyroglutamic acidosis, especially in patients with risks factors (see section 4.4)
Salicylates - may enhance the effect of anticoagulants and inhibit the uricosuric effect of probenecid, they can also potentiate metoclopramide. Antacids in large doses may reduce plasma concentrations by hastening renal excretion of sodium salicylate.
4.6 Fertility, Pregnancy and lactation
Pregnancy:
Epidemiological studies on neurodevelopment in children exposed to paracetamol in utero show inconclusive results. If clinically needed, paracetamol can be used during pregnancy however it should be used at the lowest effective dose for the shortest possible time and at the lowest possible frequency. There is clinical and epidemiological evidence of the safety of aspirin in human pregnancy, but it may prolong labour and contribute to maternal and neo-natal bleeding and so it is best avoided during the last 3 months of pregnancy.
From the 20th week of pregnancy onward, sodium salicylate use may cause oligohydramnios resulting from foetal renal dysfunction. This may occur shortly after treatment initiation and is usually reversible upon discontinuation. In addition, there have been reports of ductus arteriosus constriction following treatment in the second trimester, most of which resolved after treatment cessation. Therefore, during the first and second trimester of pregnancy, sodium salicylate should not be given unless clearly necessary. If sodium salicylate is used by a woman attempting to conceive, or during the first and second trimester of pregnancy, the dose should be kept as low and duration of treatment as short as possible. Antenatal monitoring for oligohydramnios and ductus arteriosus constriction should be considered after exposure to sodium salicylate for several days from gestational week 20 onward. sodium salicylate should be discontinued if oligohydramnios or ductus arteriosus constriction are found.
During the third trimester of pregnancy, all prostaglandin synthesis inhibitors may expose the foetus to:
- cardiopulmonary toxicity (premature constriction/closure of the ductus arteriosus and pulmonary hypertension);
- renal dysfunction (see above);
the mother and the neonate, at the end of pregnancy, to:
- possible prolongation of bleeding time, an anti-aggregating effect which may occur even at very low doses;
- inhibition of uterine contractions resulting in delayed or prolonged labour.
Consequently, sodium salicylate is contraindicated during the third trimester of pregnancy (see sections 4.3 and 5.3).
Breast-feeding:
Paracetamol is excreted in breast milk but not in a clinically significant amount. Available published data on paracetamol does not contraindicate breast feeding.
4.7 Effects on ability to drive and use machines
Doans backache pills has no or negligible influence on the ability to drive and use machines.
4.8 Undesirable effects
Side effects with Doans backache pills are rare in therapeutic doses. Paracetamol has been widely used and reports of adverse reactions are rare and are generally associated with overdosage. Hypersensitivity including skin rash may occur. Very rare cases of serious skin reactions have been reported. Isolated cases of thrombocytopenic purpura, methaemoglobinaemia, agranulocytosis, nausea and vomiting have been reported. Isolated cases of chronic hepatic necrosis, acute pancreatitis and nephrotoxicity have been reported after overdosage or prolonged administration. Salicylates may induce hypersensitivity, asthma, urate kidney stones, gastro-intestinal irritation, acute and chronic gastro-intestinal blood loss, tinnitus, nausea and vomiting.
Metabolism and nutrition disorders
Not known: High anion gap metabolic acidosis
Description of selected adverse reactions
High anion gap metabolic acidosis
Cases of high anion gap metabolic acidosis due to pyroglutamic acidosis have been observed in patients with risk factors using paracetamol (see section 4.4). Pyroglutamic acidosis may occur as a consequence of low glutathione levels in these patients.
Reporting of suspected adverse reactions
Reporting suspected adverse reactions after authorisation of the medicinal products is important. It allows continued monitoring of the benefit/risk balance of the medicinal product. Healthcare professionals are asked to report any suspected adverse reactions via the Yellow Card Scheme Website: www.mhra.gov.uk/yellowcard or search for MHRA Yellow Card in the Google Play or Apple App Store.
4.9 Overdose
Overdose should be immediately treated by inducing emesis and gastric lavage. Vital functions should be monitored and supported. Symptoms of paracetamol overdosage in the first 24 hours are pallor, nausea, vomiting, anorexia, and abdominal pain. Liver damage may become apparent 12 to 48 hours after ingestion. Overdose should be immediately treated by inducing emesis and gastric lavage. Abnormalities of glucose metabolism and metabolic acidosis may occur. In severe poisoning hepatic failure may progress to encephalopathy, coma and death. However, it should be noted that patients who have taken an overdose of paracetamol may appear well for the first three days then succumb with liver damage. The hepatic changes produced by overdosage of paracetamol result from the accumulation of a highly reactive intermediate metabolite in the hepatocytes. Acute renal failure with acute tubular necrosis may develop even in the absence of severe liver damage. Cardiac arrhythmias, pancreatitis and death have been reported. Liver damage is possible in adults who have taken 10g or more of paracetamol. It is considered that excess quantities of toxic metabolites (usually adequately detoxified by glutathione when normal doses of paracetamol are ingested) become irreversibly bound to liver tissue. Immediate treatment is essential in the management of paracetamol overdosage. Despite a lack of significant early symptoms, patients should be referred to hospital urgently for urgent medical attention and any patient who had ingested around 7.5g or more of paracetamol in the preceding 4 hours should undergo gastric lavage. Administration of oral methionine or intravenous N-acetylcysteine which may have a beneficial effect up to at least 48 hours after the overdose, may be required. General supportive measured must be available.
Overdosage with salycilates may produce dizziness, tinnitus, vasodilatation, sweating nausea and vomiting contusion and hyperventilation. Gross overdosage may lead to CNS depression with coma, cardiovascular collapse and respiratory depression. If overdosage is suspected, the patient should be kept under observation for at least 24 hours, as symptoms and salicylate blood levels may not become apparent for several hours. Treatment of overdosage consists of gastric lavage and forced alkaline diuresis. Haemodialysis may be necessary in severe cases.
5 PHARMACOLOGICAL PROPERTIES
5.1 Pharmacodynamic properties
Pharmacotherapeutic group: Analgesics
ATC code: N02BE01
Sodium Salicylate is an inhibitor of prostaglandin synthetase and acts as a non-steroidal anti-inflammatory analgesic drug.
Paracetamol is an analgesic acting on the central nervous system.
5.2 Pharmacokinetic properties
Paracetamol is readily absorbed from the gastro-intestinal tract with peak plasma concentrations occurring about 30 minutes to 2 hours after ingestion. It is metabolised in the liver and excreted in the urine mainly as the glucuronide and sulphate conjugates. Less than 5% is excreted as unchanged paracetamol. The elimination half-life varies from about 1 to 4 hours. Plasma protein binding is negligible at usual therapeutic concentrations but increases with increasing concentrations. A minor hydroxylated metabolite which is usually produced in very small amounts by mixed-function oxidases in the liver and which is usually detoxified by conjugation with liver glutathione may accumulate following paracetamol overdosage and cause liver damage.
Sodium salicylate, like aspirin, is absorbed in the stomach, but probably at a greater rate than aspirin. Acetysalicylates and salicylates are also readily absorbed from the intestine, but this may be reduced in the case of sodium salicylate by the concomitant administration of alkalis.
Hydrolysis to salicyclic acid occurs rapidly in the intestine and in the circulation. Salicylates are extensively bound to plasma proteins. Salicylates are rapidly distributed to all body tissues; they appear in milk and cross the placenta. The rate of excretion of salicylates varies with the pH of the urine, increasing as the pH rises and being greatest at pH 7.5 and above. Salicylates are excreted as salicyclic acid and as glucoronide conjugates and as salicyluric and gentisic acids.
5.3 Preclinical safety data
Conventional studies using the currently accepted standards for the evaluation of toxicity to reproduction and development are not available.
6 PHARMACEUTICAL PARTICULARS
6.1 List of excipients
Core
Microcrystalline cellulose
Sodium starch glycollate
Colloidal anhydrous silica
Magnesium stearate
Stearic acid
Film Coat
Hydroxypropyl methyl cellulose Polysorbate 80
Opaspray green M-I-3888B (E171,E172,E464) Purified talc
6.2 Incompatibilities
None.
6.3 Shelf life
36 months.
6.4 Special precautions for storage
Store below 25ºC.
6.5 Nature and contents of container
Child resistant blister packs made of 250μm white opaque rigid UPVC backed with 15μm PVC / 20μm aluminium foil.
Pack size: 8,16.
6.6 Special precautions for disposal
Medicines should be kept out of the reach of children.
7 MARKETING AUTHORISATION HOLDER
Bristol Laboratories Limited
Unit 3, Canalside, Northbridge road Berkhamsted
Herts
HP4 1EG
UK
8 MARKETING AUTHORISATION NUMBER(S)
PL 17907/0444
9 DATE OF FIRST AUTHORISATION/RENEWAL OF THE
AUTHORISATION
2nd February 2005
10 DATE OF REVISION OF THE TEXT
20/01/2025