Drugs for Skin, Muscle, and Bone

Introduction

There are various drugs used for treatment of disorders, illnesses, and malfunctions in the integumentary and musculoskeletal system. Each drug has a different function to relieve or treat the symptom of a patient. Your career in the healthcare field will require an understanding of these drugs since you'll be working with a variety of patients.

 

Integumentary Drug Classifications

The integumentary system comprises the skin, hair, nails, glands, and nerves of the body. The skin protects the body and acts as a barrier from the elements of the world. The drugs listed are used to treat conditions, diseases, and common issues of the skin.

Topical corticosteroids are anti-inflammatory drugs applied to the surface of the skin to relieve three common symptoms of skin disorders: pruritis (itching), vasodilation (dilation of blood vessels), and inflammation.

Antipruritics prevent or relieve itching.

Antiseptics are topically applied agents that destroy bacteria. They prevent the development of infections in cuts, scratches, and surgical incisions. 

Keratolytics destroy and soften the outer layer of the skin so that it can be shed. Certain keratolytics such as salicylic acid are effective for removing warts and corns. Other keratolytics are used to promote the shedding of scales and crusts in eczema, psoriasis, and seborrheic dermatitis.

Antiparasitics, as the name suggests, kill insect parasites that infest the skin. For example, medications such as mebendazole, albendazole, or ivermectin treat pinworm infections. Scabicides kill mites that cause scabies. Examples include permethrin cream and sulfur ointment. pediculicides kill lice that cause pediculosis. Pyrethrins and permethrin lotions are examples of medications used to treat lice.

Protectives and astringents are used to cover, cool, dry, or soothe inflamed skin. Protectives don't penetrate the skin or soften it but form a long-lasting film. This film protects the skin from air, water, and clothing during the natural healing process. Astringents shrink the blood vessels locally, dry up secretions from seeping lesions, and lessen the sensitivity of the skin.

Topical anesthetics are prescribed for pain on skin surfaces or mucous membranes caused by wounds, hemorrhoids, or sunburns. These topical anesthetics relieve pain and itching by numbing the nerves in the skin layer or mucous membranes. They're applied directly to the painful areas by means of sprays, creams, gargles, suppositories, and other preparations.

 

There are many medications that are available as eyedrops to treat a variety of conditions including infection, redness, dryness, irritation, and glaucoma. Eyewashes are used to flush and bathe the eye, usually to remove foreign particles or chemical irritants. We'll discuss eyedrops and eyewashes in more detail when we cover drugs related to the sensory system.

 

Sunburn is caused by an abundance of ultraviolet rays hitting the skin. Mild sunburn is tender to the touch, and the patient may complain of a hot, tight feeling to the skin. A patient with more severe sunburn may experience intense pain, inability to tolerate contact with clothing, and symptoms of fever and chills.

Local anesthetics are useful in relieving the pain associated with sunburn. Protectants are often included with the anesthetic to provide additional relief for the burning sensation. These protectants include cocoa butter, glycerin, shark liver oil, and petrolatum (petroleum jelly).

 

Sunscreens are used to protect the skin from the sun's UV rays and prevent sunburn. They also protect exposed areas of the body in susceptible individuals from the long-term hazards of skin cancer and premature aging.

An important measure of sunscreens is the sun protection factor (SPF). The SPF measures the time it takes for skin to be visibly damaged by sun exposure from the UVB rays of the sun.

The higher the SPF number, the greater the protection from the sun's rays. For example, an individual who would start to burn after 10 minutes would theoretically be protected from burning for 150 minutes when using sunscreen with an SPF factor of 15.

Most of the products on the market contain a combination of sunblock of agents. Opaque sunblock agents are visible when applied to the skin. They're used by people who can tolerate very little exposure to the sun. Zinc oxide ointment is the sunblock favored by most people.

 

The Skin Cancer Foundation recommends using a product with an SPF factor of 15 every day for everyone over the age of six months. People who are in the sun more may require higher SPF sunscreens that are water-resistant. Every sunburn increases a person's risk of developing skin cancer. But it's also important to understand that even without a sunburn, the skin can be experiencing damage from UVA exposure.

More than 20 chemical agents have been proven to be effective as sunscreens and sunblocks. These chemicals include aminobenzoic acid, ethylhexyl p-methoxycinnamate, and menthyl anthranilate. The commercial products all contain one of these agents or a combination of several.

There are three types of sunscreens:

• Sunburn preventive agents
• Sun-tanning agents
• Opaque sunblock agents

 

External Analgesics

External analgesics are topically applied agents with analgesic, anesthetic, anti-itching, and counterirritant effects. They can reduce symptoms caused by burns, cuts, abrasions, insect bites, and skin lesions. The analgesic and anesthetic effects result from the depression of the skin receptors for pain, itching, and burning. Topical analgesics and anesthetics include benzocaine, tetracaine, dibucaine, lidocaine, benzyl alcohol, and dyclonine hydrochloride. Some of these agents may be available as lozenges or sprays for sore throat or as an ointment/cream for a painful sensation on the skin. One example of a topical anti-itching agent is diphenhydramine. Topical corticosteroids may also be used to treat itching due to a rash, eczema, or hemorrhoids.

Cold sores are caused by a virus and are difficult to treat. Medications help with the pain associated with cold sores and contain an astringent, or drying agent (benzyl alcohol, zinc sulfate); a protectant (dimethicone); a counterirritant to help with itching (menthol, camphor, phenol); and a topical anesthetic to help numb the area (benzocaine, dyclonine, dibucaine). One product, however, is different. Docosanol (Abreva) is the only product that has antiviral properties; thus, it helps to shorten the severity and duration of cold sores, especially if used at the onset of the cold sore.

 

Counterirritant effects are the mainstays of these external products. Counterirritants are applied to produce a mild, local, inflammatory reaction with the objective of providing relief in another site, usually next to or underlying the skin surface being treated. The counterirritant drug is usually applied to the skin where pain is experienced. The counterirritants found in commercial analgesic rubs include:

1. Oils, such as eucalyptus or turpentine

2. Methyl salicylate 

3. Menthol

4. Capsicum preparations

5. Camphor

 

Topical anti-infectives are used to counteract local infections of the skin or mucous membranes caused by bacteria or fungi. Most bacterial infections occur as localized skin infections and are caused by strains of staphylococcus. Gram-negative anaerobic bacteria may also cause skin infections. Fungal infections often last longer than bacterial infections and are sometimes more difficult to eliminate.

Antibacterial components of topical anti-infectives include bacitracin, polymyxin B sulfate, and neomycin. Antifungal components of these products include undecylenic acid and miconazole. As you learned previously the antiviral docosanol is a component in the cold sore medication Abreva.

There are also many topical products available for the treatment of fungal infections. The most common fungal infections include athlete's foot and vaginal yeast infections. Antifungal preparations to treat yeast infections are available as creams and vaginal suppositories for internal use. Many of these also come with a small tube of cream for external use for relief of itching and discomfort. There are seven-day, three-day, and one-day regimens (drug-dosing intervals) available. The active ingredients in these preparations include miconazole, butoconazole, clotrimazole, and tioconazole. Some of these same agents are available in creams or sprays to treat athlete's foot.

 

Topical corticosteroids treat atopic dermatitis and contact dermatitis. Atopic dermatitis is one of the most common skin disorders seen in children and young adults. Symptoms of atopic dermatitis are scaling, reddening, and weeping of the skin and serious itching. The cause is unknown. Contact dermatitis is a similar condition, but the symptoms occur because of contact with an irritating substance such as poison ivy, soap powders, or latex gloves. Topical corticosteroids are available in creams and ointments, and are effective in treating these two types of dermatitis.

Topical corticosteroids should be applied sparingly (in very small amounts) as recommended by a healthcare provider. Although many patients will tend to apply large amounts of hydrocortisone, assuming that more is better, this is incorrect, and much of the cream goes to waste. Healthcare providers should instruct patients to apply a thin film to the area and massage it into the skin thoroughly. Additionally, patients should make sure they're applying corticosteroids to intact skin only.

 

Drugs Used in the Musculoskeletal System

Muscles may become sore or inflamed through overuse or injury, resulting in pain and tenderness. 

Muscle spasms may occur because of overuse, dehydration, or low potassium levels. Muscle spasms can be acute and happen infrequently, or may be a long term issue.

Spasticity is defined as stiffness in the muscles and sustained, involuntary muscle spasms. This is a symptom that may occur in patients with multiple sclerosis or spinal cord injuries.

Drugs used to treat muscle spasms:

There are a few different medications used to treat muscle spasms. Patients that have acute spasms may take medications such as cyclobenzaprine, methocarbamol, carisoprodol, or metaxalone. Baclofen, tizanidine, or dantrolene may be used more long-term for spasticity. Benzodiazepines such as diazepam may be considered as adjunct therapy for spasticity; they're generally avoided for patients with acute muscle spasms because of the likelihood for tolerance and dependence.

 

Key Points

• Topical corticosteroids are anti-inflammatory drugs applied to the skin to relieve itching, dilation of blood vessels, and inflammation. Topical corticosteroids treat atopic dermatitis and contact dermatitis.
• Antiseptics are topically applied agents that prevent infection by destroying bacteria.
• Keratolytics destroy and soften the outer layer of skin so that it can be shed; they're often used to remove corns and warts.
• Parasiticides kill parasites that infest the skin.
• Protectives are used to cover, cool, dry, or soothe inflamed skin.
• Topical anesthetics are used to treat pain on the skin or mucous membranes.
• Eyedrops are used to treat irritation and dryness of the eye; eyewashes are used to flush and bathe the eye.
• Sunburn preparations treat sunburn, which is caused by too much ultraviolet light hitting the skin.
• External analgesics are topically applied agents with analgesic, anesthetic, anti-itching, and counterirritant effects.
• Topical anti-infectives are used to counteract local infections of the skin or mucous membranes caused by bacteria or fungi.