Definition
Drugs today usually contain a defined active pharmaceutical ingredient. However, numerous drugs with two or more active substances also exist. These are called combination drugs or fixed combinations. For example, Aspirin C contains both acetylsalicylic acid and vitamin C. Many blood pressure medications are combination preparations, for example perindopril + indapamide or candesartan + hydrochlorothiazide. This combines different mechanisms of action. Active ingredients can also be added to counteract resistance (e.g., amoxicillin + clavulanic acid) or to influence pharmacokinetics – see under pharmacokinetic booster. Side effects are also reduced, e.g., constipation under oxycodone with the addition of naloxone. The agents may be used for the same or for different complaints. If the second case applies, the term “polysymptomatologics” is rarely used. The fact that it is a combination may already be apparent from the drug name, for example, the prefix Co- and Duo- or the addition of HCT, Complex, and Comp.
Advantages
The use of combination medications reduces the number of medications that patients must administer. For example, one tablet is sufficient instead of two or three. This applies not only to oral dosage forms, but also to injections or ointments, for example. This simplifies pharmacotherapy and can have a positive influence on compliance. Depending on their composition, combination preparations can increase efficacy, improve pharmacokinetic properties, and reduce resistance and side effects.
Disadvantages
With fixed combinations, flexibility is reduced. For example, if one of the active ingredients is not tolerated, it cannot be omitted. Changes in therapy are also less easy to implement. Ill-considered use can burden the organism with unnecessary substances.
Examples
Strength Effect:
- Valsartan + hydrochlorothiazide
- Atorvastatin + ezetimibe
- IDegLira: insulin degludec + liraglutide
- Efavirenz + emtricitabine + tenofovir
- Vitamin C + Zinc
- Sofosbuvir + Ledipasvir
- Latanoprost + timolol
- Sitagliptin + metformin
Against resistance:
- Amoxicillin + clavulanic acid
- Piperacillin + tazobactam
Influence on pharmacokinetics:
- Levodopa + benserazide / carbidopa.
- Darunavir + cobicistat
Fewer side effects:
- Oxycodone and naloxone
- Meclozine + caffeine + pyridoxine
Miscellaneous symptoms:
- Phenylephrine + pheniramine + vitamin C + acetaminophen.
- Betamethasone + clotrimazole + gentamicin
Notes
- A monopreparation is in medicinal product that contains only one active ingredient.
- Combination therapy does not automatically include a combination drug. It can also be carried out with monopreparations.
- If a combination preparation is not available, it can be replaced by the corresponding monopreparations, if necessary.
