Aspirin/ Caffeine

Brands of  Aspirin/ Caffeine in Kenya

Mifupen, Elys Chemical Industries Ltd
Nopen, Laboratory & Allied Ltd


Acetylsalicylic acid (ASA) blocks prostaglandin synthesis. It is non-selective for COX-1 and COX-2 enzymes. Inhibition of COX-1 results in the inhibition of platelet aggregation for about 7-10 days (average platelet lifespan).

Caffeine action is thought to be mediated via several mechanisms: the antagonism of adenosine receptors, the inhibition of phosphodiesterase, the release of calcium from intracellular stores, and antagonism of benzodiazepine receptors


For the treatment of mild to moderate pain including headache, migraine, neuralgia, toothache, sore throat, period pains and aches and pains.

For the symptomatic treatment of sprains, strains, rheumatic pain, sciatica, lumbago, fibrositis, muscular aches and pains, joint swelling and stiffness, influenza, feverishness and feverish colds.


Adults, the elderly and young persons aged 16 and over:

2 tablets every 4 hours to a maximum of 12 tablets in 24 hours.

Do not exceed 12 tablets in 24 hours.

Do not give to children aged under 16, unless specifically indicted (e.g. Kawasaki’s disease).


Hypersensitivity to the active ingredients or any of the other constituents. Peptic ulceration and those with a history of peptic ulceration; haemophilia, concurrent anti-coagulant therapy; children under 16 years and when breast feeding because of possible risk of Reyes Syndrome.


Other NSAIDs and corticosteroids: Concurrent use of other NSAIDs or corticosteroids may increase the likelihood of GI side effects.

Diuretics: Antagonism of the diuretic effect.

Anticoagulants: Increased risk of bleeding due to antiplatelet effect.

Metoclopramide: Metoclopramide increases the rate of absorption of aspirin. However, concurrent use need not be avoided.

Phenytoin: The effect of phenytoin may be enhanced by aspirin. However, no special precautions are needed.

Valproate: The effect of valproate may be enhanced by aspirin.

Methotrexate: Delayed excretion and increased toxicity of methotrexate.

Warfarin: Low-dose aspirin (75 to 325 mg daily) increases the risk of bleeding when given with warfarin. High doses of aspirin (4 g daily or more) can also increase prothrombin times in patients taking warfarin. Avoid high-dose aspirin. If low-dose aspirin is indicated, monitor for signs of bleeding. Consider giving gastroprotection (e.g. a proton pump inhibitor) to at-risk patients.

Sulfinpyrazone: The uricosuric effects of aspirin and sulfinpyrazone are mutually antagonistic. Concurrent use for uricosuria should be avoided. Doses of aspirin as low as 700 mg can cause an appreciable fall in uric acid excretion but the effects of a small dose are probably of little practical importance. Sulfinpyrazone can cause gastric bleeding and inhibit platelet aggregation which may be additive with aspirin. (Severity – moderate).

Blood pressure lowering treatments (ACE inhibitors): High-dose aspirin can reduce the antihypertensive efficacy of ACE inhibitors. Low-dose aspirin (100 mg daily or less) appears to have little effect. It is unclear if aspirin attenuates the benefits of ACE inhibitors in heart failure: the likelihood of an interaction possibly depends on disease state and its severity. (Severity – moderate).

Antacids: The serum salicylate concentrations of patients taking aspirin have been reduced to subtherapeutic levels by aluminium and magnesium hydroxide. Care should be taken to monitor serum salicylate levels if any antacid is started or stopped in patients where the control of salicylate levels is critical. Occasional doses of aspirin for analgesia and aspirin given in doses that produce low salicylate levels do not appear to be affected. (Severity – moderate).

Cilostazol: Concurrent use of multiple antiplatelets would be expected to increase the risk of bleeding. Aspirin very slightly increases the exposure to cilostazol with no clinically relevant effect on bleeding times. Be aware of the increased risk of bleeding. Cilostazol is contraindicated with two or more antiplatelets or anticoagulants (UK). (Severity – moderate).

Mifepristone: Theoretically aspirin and NSAIDs might reduce the efficacy of mifepristone. However, evidence from two studies with naproxen and diclofenac suggests no reduction in mifepristone efficacy. No action needed. (Severity – moderate but theoretical).

Probenecid: The uricosuric effects of aspirin and probenecid are mutually antagonistic. Low dose, enteric-coated aspirin appears not to interact. Regular dosing with substantial amounts of salicylates should be avoided, but small very occasional analgesic doses probably do not matter. Serum salicylate levels of 5 to 10 mg/100 mL are necessary before this interaction occurs. (Severity – moderate).

Venlafaxine/SSRIs: The bleeding risk associated with antiplatelet drugs such as aspirin might be further increased by the concurrent use of an SNRI/SSRI. Advise patients to report bleeding. Consider gastroprotection (such as a proton pump inhibitor) in those at high risk of gastrointestinal bleeding (e.g. history of gastrointestinal bleeding, the elderly). (Severity – severe).

Sympathomimetics: Caffeine acts synergistically towards the hypertensive and tachycardic effects of sympathomimetics.


Side effects are mild and infrequent, but there is a high incidence of gastro-intestinal irritation with slight asymptomatic blood loss. Increased bleeding time. Aspirin may precipitate bronchospasm and induce asthma attacks or other hypersensitivity reactions in susceptible individuals. Aspirin may induce gastro-intestinal haemorrhage, occasionally major. It may precipitate gout in susceptible individuals. Possible risk of Reye’s Syndrome in children under 16 years.

High doses of caffeine can cause tremor and palpitations.

Reporting of suspected adverse reactions:

The PPB Department of Pharmacovigilance was set up with a vision to develop, implement and continuously upgrade an appropriate system for detecting, reporting, and monitoring adverse drug reactions (ADRs) and other relevant problems with medicines in Kenya. The department strives to ensure the safety and efficacy of pharmaceutical products in Kenya.
Reporting suspected adverse reactions after authorization of the medicinal product are important. It allows continued monitoring of the benefit/risk balance of the medicinal product. Healthcare professionals/ Patients are encouraged to report any suspected adverse reactions via Pharmacovigilance Yellow Form, or clicking below button:

Clinical | Pharmacokinetic data

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References/ Citation:

  1. Hudson, Geoffrey M., et al. “Effects of caffeine and aspirin on light resistance training performance, perceived exertion, and pain perception.” The Journal of Strength & Conditioning Research 22.6 (2008): 1950-1957.

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