Here's something I wrote on over-the-counter medicines.

Go easy on decongestants as they're bad for you with lots of side effects. Pay especial attention to pain relief as one medicine is not appropriate to another age group.

If a respiratory infection, the main goal is usually to get mucus out. That requires an expectorant. Suppresants stop your coughing, but that's bad since the mucus continues to build up, and eventually lowers you oxygen levels (O2 Sats). If the patient is bluish, their oxygen levels are very low, they need medical attention.

Over-the-counter medicines
What do those ingredients do?

Be careful taking over-the-counter medicines. Many contain ingredients which could be bad for you depending upon your age, your medical conditions, or the medications you're taking.

Common ingredients include:
Pain
1.Aspirin for pain relief, but children shouldn't take it because of Reye Syndrome.
2.Acetaminophen is often given to children but shouldn't be taken by older folks as it's metabolized by the liver and difficult for them to process. Expired acetaminophen is a poison. Check those dates.
3.Naproxen is an excellent pain reliever as it's stronger, but shouldn't be taken by some older folks since metabolized by the liver. Can't take it if you have ulcers, or heart problems.
4.Ibuprofen is a good pain reliever but has a lot of side effects. Not recommended.

Decongestant by definition constrict the blood vessels and sinuses. Not a good idea if on blood pressure medications, right? They also can make you nervous or irritable. Some are restricted. I'm not big on these.
1.Pseudoephedrine: very restricted
2.Phenylephrine : not restricted

Take horseradish to open your sinuses instead. Then a nasal rinse with boiled water and salt. Let it cool obviously.

Expectorants: expel mucus
1.Guaifenesin: very helpful but can't take it if prone to nausea or vomiting. Could exacerbate kidney stones.
2.Ambroxol : not over-the-counter in the USA, but elsewhere. Very helpful. Can't be taken by pregnant women, infants shouldn't take it.
3.Acetylcysteine: might harm the heart and lungs. If you issues with either, I wouldn't use it.

Cough Suppressant ( strong antitussive)
1.Dextromethorphan: Has a lot of side effects like nausea, rash, sleepiness, breathing difficulty, hallucination. Not recommended except times when you need to rest.
2.Noscapine: strong antitussive but a lot of side effects

Use Honey and Lemon instead.

Slippery Elm is a demulcent. It coats and soothes the throat, but it might interfere with absorbtion of your medications. It's best used for sore throat pain and to help dry coughs.

Licorice Root: Opens the airway, stimulates the immune system (eosinophils), and reduces inflammaiton. Can't use it if on heart medications. If you're a smoker, you're getting licorice as an additive. A heart patient who smokes is really messing up if using a tobacco with this.

One could easily take brewed tea of ginger, garlic, onion and eliminate a lot of issues. It's cheaper and no side effects too.

If you can't mess around with making something try Traditional Medicinals Breathe Easy Tea or Throat Coat Tea based upon your symptoms. Both are cheap, locally available, and mild.If you take one with licorice root, you may get buzzy if you drink too much of it. Back off then. Follow the directions.