Apomorphine, the sole drug approved as an acute rescue therapy for Parkinson’s Disease “freezing” episodes. (Image: Wikimedia Commons) The highest-profile symptoms of major diseases are well publicized. Yet, for many, the side effects of mainstream therapies for these diseases can also impact physical and psychological well-being. Luckily, advances in drug delivery have offered novel treatments, and more are being developed today. In what follows, we look at some examples.
A look at drug-induced adverse effects
First, cancer treatment, including chemotherapy and radiation therapy, can produce low blood cell counts, leading to complications. These therapies risk damaging bone marrow, where blood cells are created. A low white blood cell count (neutropenia) leaves the body more prone to infection, while a low red blood cell count means low hemoglobin level, which can produce anemia, bleeding and fatigue. 
As another example, nausea is one of the most common medication side effects that patients report both from chemotherapy and other treatments, as virtually all agents have the ability to cause stomach disturbances. Medication-related nausea can have a profound impact on patient outcomes because nonadherence to prescribed therapy can result in treatment failure. Agents that trigger nausea include dopaminergic agonists, digoxin, opiates, nonsteroidal anti-inflammatory drugs (NSAIDs) and erythromycin. 
A further arena involves the treatment of side effects triggered by the use of antipsychotics by the elderly. Drug-induced parkinsonism, characterized by tremors, is a common side effect of conventional antipsychotic treatment. This condition can cause discomfort and often contributes to falls in older adults. Benztropine is commonly prescribed for the purpose of treating drug-induced parkinsonism. 
Addressing drug-induced adverse effects
Fortunately, innovation addressing side effects is ongoing. For an example, consider hay fever, a condition marked by symptoms that can include sneezing, runny nose, itchy eyes, loss of sense of smell and facial pain due to blocked sinuses. Current treatments for hay fever include antihistamines and corticosteroids. Each of these treatments, however, presents its own side effects. The side effects of antihistamines include drowsiness, impaired thinking, dry mouth and constipation; while steroids on a long-term basis can cause weight gain, acne, stomach ulcers and can make patients vulnerable to infections.
To counter these side effects, researchers in the UK have devised a nasal spray containing a cellulose powder; when puffed up the nose, it reacts with moisture in the nasal cavity to create a gel barrier against the pollen to which hay fever sufferers are allergic. Results published in the International Archives of Allergy and Immunology1 showed that study participants who used the cellulose powder saw their symptoms improve while those given a placebo showed little or no change. No clinically significant side effects were reported.
For another example, consider the case of Parkinson’s disease (PD). One PD side effect is “freezing” episodes, characterized by acute immobility. These episodes are triggered by levodopa or enzyme inhibitors—both mainline treatments for PD. The episodes begin when the levodopa or enzyme inhibitors enter the bloodstream too slowly, or wear off quickly, or just do not enter the bloodstream sufficiently at all.
The sole drug approved as an acute rescue therapy to treat these “freezing” episodes is the dopamine agonist apomorphine (marketed under the name Apokyn in the U.S. and Japan and APO-go in Europe and parts of Asia). Some patients using Apokyn experience significant nausea for the first few months of treatment with it. As a countermeasure, they can be prescribed the anticholinergic Tigan (trimethobenzimide) in the United States a few days before beginning Apokyn, and within three to six months almost all no longer require Tigan. 
Another issue with Apokyn is that it is primarily available in an inconvenient, painful injectable form and as an infusion pump in Europe—problematic not only because it requires administration up to several times daily, but also because the injection can result in irritation and nodules at the injection site on the body, since apomorphine is only stable in a highly acidic formulation. One approach to this problem currently in clinical development involves a sublingual thin-film strip system, called APL-130277, that can deliver the drug into the bloodstream in a similar time interval and a similar concentration as an injectable dose. 
Given the ongoing demand to address side effects of mainstream drugs, the innovation embodied by the examples above will continue to be welcomed.
1. Åberg N, Ospanova ST, Nikitin NP, Emberlin J, Dahl Å. A nasally applied cellulose powder in seasonal allergic rhinitis in adults with grass pollen allergy: a double-blind, randomized, placebo-controlled, parallel-group study. Int Arch Allergy Immunol. 2014;163(4):313-318.