Rasa Nyeri (Pain)

Nyeri merupakan perasaan tidak menyenangkan yang merupakan pertanda bahwa tubuh telah mengalami kerusakan atau terancam oleh suatu cedera. Jadi nyeri dalam kebanyakan hal hanya merupakan suatu gejala, yang berfungsi melindungi tubuh. Nyeri harus dianggap sebagai isyarat bahaya tentang adanya gangguan di jaringan, seperti peradangan, infeksi jasad renik, atau kejang otot. Nyeri yang disebabkan oleh rangsangan mekanis, kimiawi, atau fisis (kalor, listrik) dapat menimbulkan kerusakan pada jaringan. Rangsangan tersebut memicu pelepasan zat – zat tertentu yang disebut mediator nyeri.

Nyeri berawal dari reseptor nyeri yang tersebar di seluruh tubuh. Reseptor nyeri ini menyampaikan pesan sebagai impuls listrik di sepanjang saraf yang menuju ke medula spinalis dan kemudian diteruskan ke otak. Kadang ketika sampai di medula spinalis, sinyal ini menyebabkan terjadinya respon refleks; jika hal ini terjadi, maka sinyal segera dikirim kembali di sepanjang saraf motorik ke sumber nyeri dan menyebabkan terjadinya kontraksi otot. Contoh dari respon refleks adalah reaksi segera menarik tangan ketika menyentuh sesuatu yang sangat panas. Sinyal nyeri juga sampai ke otak. Seseorang akan akan merasakan nyeri hanya jika otak mengolah sinyal ini dan mengartikannya sebagai nyeri.

Setiap orang memiliki tingkat toleransi yang berbeda terhadap nyeri, seseorang bisa merasakan nyeri yang hebat karena tergores atau mengalami memar, sedangkan yang lainnya hanya sedikit mengeluh meskipun mengalami kecelakaan berat.

Nyeri dapat bersifat tajam atau tumpul, terus menerus atau hilang-timbul, berdenyut-denyut atau menetap, di satu tempat atau di beberapa tempat. Intensitasnya bervariasi mulai dari yang ringan, sedang, bahkan sampai nyeri yang tak tertahankan.

Pengobatan simptomatik yang ditujukan untuk menghilangkan nyeri tanpa menghiraukan pernyebab yaitu dengan menggunakan obat – obat analgetik.

Obat analgetik yang digunakan berbeda-beda tergantung tingkatan nyeri yang diakibatkan proses keganasan tersebut dengan mengacu pada pemeriksaan VAS (visual analog scale).

berikut menampilkan visual analog scale yang digunakan untuk menentukan derajat nyeri.

Tabel 1 menampilkan visual analog scale yang digunakan untuk menentukan derajat nyeri.

Pain Rating Scales
Descriptive scale
Circle the word that best describes your pain.
None Bothersome Uncomfortable Moderate Severe Excruciating
Numerical scale
Circle the number that best describes the severity of your pain.
0 1 2 3 4 5
Visual analog scale
Mark the place on this line that best describes the severity of your pain.
No distress/no pain ___________________________________________________ Worst pain ever
Functional interference scale
Circle the word that best describes the patient’s degree of impairment.
None Minimal Housebound Limited mobility Impaired speech or eating Incapacitated
FIGURE 1.Various scales for rating pain.

Berdasarkan VAS, penanganan nyeri dibagi menjadi tiga tingkatan, yaitu:

Nyeri ringan            : Analgesik non-opioid  ±  Adjuvan terapi

Nyeri sedang          : Analgesik non-opioid  +  Analgesik opioid lemah (opioid tingkat dua)  ±  Adjuvan terapi

Nyeri berat             : Analgesik opioid kuat (opioid tingkat tiga) ± Adjuvan terapi

Tabel 2 menampilkan penanggulangan nyeri tingkat pertama yaitu nyeri ringan.

TABEL 2.2
Step 1 Drugs for Pain Management*
 

 


Drug 


Usual starting dosage 


Maximum dosage 


Cost  


Comments  


Acetaminophen 10 to 15 mg per kg 3 to 4 g per day Low Potential liver toxicity, available over the counter
Aspirin 10 to 15 mg per kg 3 to 4 g per day Low High dosages not recommended for elderly patients, available over the counter
Celecoxib (Celebrex) 100 mg twice daily 200 mg three times daily Very high Useful in those at risk for upper gastrointestinal tract bleeding
Fenoprofen (Nalfon) 200 mg four times daily 800 mg four times daily Low
Flurbiprofen (Ansaid) 50 to 100 mg twice daily 100 mg three times daily Medium
Ibuprofen 400 mg every 6 to 8 hours 800 mg four times daily Low Available over the counter
Indomethacin (Indocin) 25 mg three times daily 50 mg four times daily Low High dosages not recommended for elderly patients
Ketoprofen (Orudis) 50 mg every 12 hours 75 mg four times daily Medium Higher than average renal excretion, available over the counter
Ketorolac (Toradol) 10 mg every 6 hours 10 mg every six hours High Not indicated for long-term use
Nabumetone (Relafen) 1 g per day 2 g per day High Can be used once a day
Naproxen (Anaprox) 275 mg every 12 hours 550 mg twice daily Low Available over the counter
Rofecoxib (Vioxx) 12.5 mg per day 50 mg per day Very high Useful in patients at risk for upper gastrointestinal tract bleeding
 


*–With the exception of acetaminophen, all of the listed medications have the potential for gastrointestinal and renal side effects.
Information from Management of cancer pain: adults. Clin Pract Guidel Quick Ref Guide Clin 1994:1-29, with additions from the author.

Tabel 3 menampilkan penanggulangan nyeri tingkat kedua yaitu nyeri sedang.

TABEL 2.3
Step 2 Drugs for Pain Management 


Drug 


Equivalent dose 


Usual starting dosage 


Maximum daily dosage 


Tramadol (Ultram) 20 mg 1 tablet (50 mg) four times daily 400 mg (8 tablets) given in divided doses every 6 hours
Aspirin with codeine no. 3 (Empirin W Codeine) 325 mg/30 mg 1 tablet four times daily 3,900 mg/360 mg (12 tablets) given in divided doses every 4 to 6 hours
Acetaminophen with codeine no. 3 (Tylenol W Codeine) 325 mg/30 mg 1 tablet four times daily 3,900 mg/360 mg (12 tablets) given in divided doses every 4 to 6 hours
Acetaminophen with oxycodone (Percocet) 325 mg/5 mg 1 tablet four times daily 3,900 mg/60 mg (12 tablets) given in divided doses every 6 hours
Aspirin with oxycodone (Percodan) 325 mg/4.9 mg 1 tablet four times daily 3,900 mg/59 mg (12 tablets) given in divided doses every 6 hours
Acetaminophen with hydrocodone (Vicodin) 500 mg/5 mg 1 tablet four times daily 4,000 mg/40 mg (8 tablets) given in divided doses every 6 hours
Morphine 5 mg 1 tablet every 4 hours No maximum dosage
Propoxyphene (Darvon)* 65 mg 1 tablet four times daily 600 mg (9 tablets) given in divided doses every 6 hours
Acetaminophen with propoxyphene (Darvocet)* 325 mg/50 mg 1 tablet four times daily 3,900 mg/600 mg (12 tablets) given in divided doses every 6 hours

*–Not recommended for long-term use.
Information from references 7, 8 and 9, with additions from the author.

Tabel 4 menampilkan penanggulangan nyeri tingkat ketiga yaitu nyeri berat.

TABEL 2.4
Step 3 Drugs for Pain Management 


Equianalgesic dosage 


Opioid drug 


Oral dosage 


Parenteral dosage 


Initial oral dosage 


Comments 


Morphine 30 mg every 3 to 4 hours 10 mg 30 mg every to 4 hours Available in a long-acting preparation
Codeine 180 mg every3 to 4 hours NA 60 mg every 3 to 4 hours Higher incidence of side effects than morphine
Oxycodone (Roxicodone) 30 mg every 3 to 4 hours 10 mg 10 mg every 3 to 4 hours Available in a long-acting preparation
Hydromorphone (Dilaudid) 7.5 mg every 3 to 4 hours 1.5 mg 6 mg every 3 to 4 hours Lower incidence of side effects than morphine
Levorphanol (Levo-Dromoran) 4 mg every 6 to 8 hours 2 mg 4 mg every 6 to 8 hours Higher incidence of side effects than morphine
Methadone 20 mg every 6 to 8 hours 10 mg 20 mg every 6 to 8 hours Lower incidence of side effects than morphine
Conversion to methadone at higher dosages may require only 3 to 5 mg per 30 mg of morphine
Oxymorphone (Numorphan) NA 1 mg every 3 to 4 hours NA
Tramadol (Ultram) 100 mg four times daily 80 mg 50 mg every 6 hours Maximum of 8 tablets per day
Fentanyl (Duragesic) 24-hour dose of any of the above is equivalent to 50 µg per hour of transdermal fentanyl 25 µg per hour patch Lower incidence of side effects than morphine
Best used in patients with stable painbecause the patch is applied only every three days
Meperidine (Demerol)* 300 mg every 3 to 4 hours 75 mg NR Possible accumulation of toxic metabolites
Butorphanol (Stadol)* NA 2 mg NA Can cause withdrawal symptoms in opioid-dependent patients
Nalbuphine (Nubain)* NA 10 mg NA Can cause withdrawal symptoms in opioid-dependent patients
Pentazocine (Talwin)* 180 mg 60 mg Can cause withdrawal symptomsin opioid-dependent patients
Buprenorphine (Buprenex)* NA 0.3 mg NA Can cause withdrawal symptoms in opioid-dependent patients

NA = not available; NR = not recommended.
*–Not recommended for use in patients with chronic cancer pain.
Information from Management of cancer pain: adults. Clin Pract Guidel Quick Ref Guide Clin 1994:1-29, and Cherny NI, Portenoy RK. The management of cancer pain. CA Cancer J Clin 1994;44:263-303, with additions from the author.

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